Provided by: perltidy_20230309-2_all 
NAME
perltidy - a perl script indenter and reformatter
SYNOPSIS
perltidy [ options ] file1 file2 file3 ...
(output goes to file1.tdy, file2.tdy, file3.tdy, ...)
perltidy [ options ] file1 -o outfile
perltidy [ options ] file1 -st >outfile
perltidy [ options ] <infile >outfile
DESCRIPTION
Perltidy reads a perl script and writes an indented, reformatted script. The formatting
process involves converting the script into a string of tokens, removing any non-essential
whitespace, and then rewriting the string of tokens with whitespace using whatever rules
are specified, or defaults. This happens in a series of operations which can be
controlled with the parameters described in this document.
Perltidy is a commandline frontend to the module Perl::Tidy. For documentation describing
how to call the Perl::Tidy module from other applications see the separate documentation
for Perl::Tidy. It is the file Perl::Tidy.pod in the source distribution.
Many users will find enough information in "EXAMPLES" to get started. New users may
benefit from the short tutorial which can be found at
http://perltidy.sourceforge.net/tutorial.html
A convenient aid to systematically defining a set of style parameters can be found at
http://perltidy.sourceforge.net/stylekey.html
Perltidy can produce output on either of two modes, depending on the existence of an -html
flag. Without this flag, the output is passed through a formatter. The default
formatting tries to follow the recommendations in perlstyle(1), but it can be controlled
in detail with numerous input parameters, which are described in "FORMATTING OPTIONS".
When the -html flag is given, the output is passed through an HTML formatter which is
described in "HTML OPTIONS".
EXAMPLES
perltidy somefile.pl
This will produce a file somefile.pl.tdy containing the script reformatted using the
default options, which approximate the style suggested in perlstyle(1). The source file
somefile.pl is unchanged.
perltidy *.pl
Execute perltidy on all .pl files in the current directory with the default options. The
output will be in files with an appended .tdy extension. For any file with an error,
there will be a file with extension .ERR.
perltidy -b file1.pl file2.pl
Modify file1.pl and file2.pl in place, and backup the originals to file1.pl.bak and
file2.pl.bak. If file1.pl.bak and/or file2.pl.bak already exist, they will be
overwritten.
perltidy -b -bext='/' file1.pl file2.pl
Same as the previous example except that the backup files file1.pl.bak and file2.pl.bak
will be deleted if there are no errors.
perltidy -gnu somefile.pl
Execute perltidy on file somefile.pl with a style which approximates the GNU Coding
Standards for C programs. The output will be somefile.pl.tdy.
perltidy -i=3 somefile.pl
Execute perltidy on file somefile.pl, with 3 columns for each level of indentation (-i=3)
instead of the default 4 columns. There will not be any tabs in the reformatted script,
except for any which already exist in comments, pod documents, quotes, and here documents.
Output will be somefile.pl.tdy.
perltidy -i=3 -et=8 somefile.pl
Same as the previous example, except that leading whitespace will be entabbed with one tab
character per 8 spaces.
perltidy -ce -l=72 somefile.pl
Execute perltidy on file somefile.pl with all defaults except use "cuddled elses" (-ce)
and a maximum line length of 72 columns (-l=72) instead of the default 80 columns.
perltidy -g somefile.pl
Execute perltidy on file somefile.pl and save a log file somefile.pl.LOG which shows the
nesting of braces, parentheses, and square brackets at the start of every line.
perltidy -html somefile.pl
This will produce a file somefile.pl.html containing the script with html markup. The
output file will contain an embedded style sheet in the <HEAD> section which may be edited
to change the appearance.
perltidy -html -css=mystyle.css somefile.pl
This will produce a file somefile.pl.html containing the script with html markup. This
output file will contain a link to a separate style sheet file mystyle.css. If the file
mystyle.css does not exist, it will be created. If it exists, it will not be overwritten.
perltidy -html -pre somefile.pl
Write an html snippet with only the PRE section to somefile.pl.html. This is useful when
code snippets are being formatted for inclusion in a larger web page. No style sheet will
be written in this case.
perltidy -html -ss >mystyle.css
Write a style sheet to mystyle.css and exit.
perltidy -html -frm mymodule.pm
Write html with a frame holding a table of contents and the source code. The output files
will be mymodule.pm.html (the frame), mymodule.pm.toc.html (the table of contents), and
mymodule.pm.src.html (the source code).
OPTIONS - OVERVIEW
The entire command line is scanned for options, and they are processed before any files
are processed. As a result, it does not matter whether flags are before or after any
filenames. However, the relative order of parameters is important, with later parameters
overriding the values of earlier parameters.
For each parameter, there is a long name and a short name. The short names are convenient
for keyboard input, while the long names are self-documenting and therefore useful in
scripts. It is customary to use two leading dashes for long names, but one may be used.
Most parameters which serve as on/off flags can be negated with a leading "n" (for the
short name) or a leading "no" or "no-" (for the long name). For example, the flag to
outdent long quotes is -olq or --outdent-long-quotes. The flag to skip this is -nolq or
--nooutdent-long-quotes or --no-outdent-long-quotes.
Options may not be bundled together. In other words, options -q and -g may NOT be entered
as -qg.
Option names may be terminated early as long as they are uniquely identified. For
example, instead of --dump-token-types, it would be sufficient to enter --dump-tok, or
even --dump-t, to uniquely identify this command.
I/O Control
The following parameters concern the files which are read and written.
-h, --help
Show summary of usage and exit.
-o=filename, --outfile=filename
Name of the output file (only if a single input file is being processed). If no
output file is specified, and output is not redirected to the standard output (see
-st), the output will go to filename.tdy. [Note: - does not redirect to standard
output. Use -st instead.]
-st, --standard-output
Perltidy must be able to operate on an arbitrarily large number of files in a single
run, with each output being directed to a different output file. Obviously this would
conflict with outputting to the single standard output device, so a special flag, -st,
is required to request outputting to the standard output. For example,
perltidy somefile.pl -st >somefile.new.pl
This option may only be used if there is just a single input file. The default is
-nst or --nostandard-output.
-se, --standard-error-output
If perltidy detects an error when processing file somefile.pl, its default behavior is
to write error messages to file somefile.pl.ERR. Use -se to cause all error messages
to be sent to the standard error output stream instead. This directive may be negated
with -nse. Thus, you may place -se in a .perltidyrc and override it when desired with
-nse on the command line.
-oext=ext, --output-file-extension=ext
Change the extension of the output file to be ext instead of the default tdy (or html
in case the --html option is used). See "Specifying File Extensions".
-opath=path, --output-path=path
When perltidy creates a filename for an output file, by default it merely appends an
extension to the path and basename of the input file. This parameter causes the path
to be changed to path instead.
The path should end in a valid path separator character, but perltidy will try to add
one if it is missing.
For example
perltidy somefile.pl -opath=/tmp/
will produce /tmp/somefile.pl.tdy. Otherwise, somefile.pl.tdy will appear in whatever
directory contains somefile.pl.
If the path contains spaces, it should be placed in quotes.
This parameter will be ignored if output is being directed to standard output, or if
it is being specified explicitly with the -o=s parameter.
-b, --backup-and-modify-in-place
Modify the input file or files in-place and save the original with the extension .bak.
Any existing .bak file will be deleted. See next item for changing the default backup
extension, and for eliminating the backup file altogether.
Please Note: Writing back to the input file increases the risk of data loss or
corruption in the event of a software or hardware malfunction. Before using the -b
parameter please be sure to have backups and verify that it works correctly in your
environment and operating system.
A -b flag will be ignored if input is from standard input or goes to standard output,
or if the -html flag is set.
In particular, if you want to use both the -b flag and the -pbp
(--perl-best-practices) flag, then you must put a -nst flag after the -pbp flag
because it contains a -st flag as one of its components, which means that output will
go to the standard output stream.
-bext=ext, --backup-file-extension=ext
This parameter serves two purposes: (1) to change the extension of the backup file to
be something other than the default .bak, and (2) to indicate that no backup file
should be saved.
To change the default extension to something other than .bak see "Specifying File
Extensions".
A backup file of the source is always written, but you can request that it be deleted
at the end of processing if there were no errors. This is risky unless the source
code is being maintained with a source code control system.
To indicate that the backup should be deleted include one forward slash, /, in the
extension. If any text remains after the slash is removed it will be used to define
the backup file extension (which is always created and only deleted if there were no
errors).
Here are some examples:
Parameter Extension Backup File Treatment
<-bext=bak> F<.bak> Keep (same as the default behavior)
<-bext='/'> F<.bak> Delete if no errors
<-bext='/backup'> F<.backup> Delete if no errors
<-bext='original/'> F<.original> Delete if no errors
-bm=s, --backup-method=s
This parameter should not normally be used but is available in the event that problems
arise as a transition is made from an older implementation of the backup logic to a
newer implementation. The newer implementation is the default and is specified with
-bm='copy'. The older implementation is specified with -bm='move'. The difference is
that the older implementation made the backup by moving the input file to the backup
file, and the newer implementation makes the backup by copying the input file. The
newer implementation preserves the file system inode value. This may avoid problems
with other software running simultaneously. This change was made as part of issue git
#103 at github.
-w, --warning-output
Setting -w causes any non-critical warning messages to be reported as errors. These
include messages about possible pod problems, possibly bad starting indentation level,
and cautions about indirect object usage. The default, -nw or --nowarning-output, is
not to include these warnings.
-q, --quiet
Deactivate error messages (for running under an editor).
For example, if you use a vi-style editor, such as vim, you may execute perltidy as a
filter from within the editor using something like
:n1,n2!perltidy -q
where "n1,n2" represents the selected text. Without the -q flag, any error message
may mess up your screen, so be prepared to use your "undo" key.
-log, --logfile
Save the .LOG file, which has many useful diagnostics. Perltidy always creates a .LOG
file, but by default it is deleted unless a program bug is suspected. Setting the
-log flag forces the log file to be saved.
-g=n, --logfile-gap=n
Set maximum interval between input code lines in the logfile. This purpose of this
flag is to assist in debugging nesting errors. The value of "n" is optional. If you
set the flag -g without the value of "n", it will be taken to be 1, meaning that every
line will be written to the log file. This can be helpful if you are looking for a
brace, paren, or bracket nesting error.
Setting -g also causes the logfile to be saved, so it is not necessary to also include
-log.
If no -g flag is given, a value of 50 will be used, meaning that at least every 50th
line will be recorded in the logfile. This helps prevent excessively long log files.
Setting a negative value of "n" is the same as not setting -g at all.
-npro --noprofile
Ignore any .perltidyrc command file. Normally, perltidy looks first in your current
directory for a .perltidyrc file of parameters. (The format is described below). If
it finds one, it applies those options to the initial default values, and then it
applies any that have been defined on the command line. If no .perltidyrc file is
found, it looks for one in your home directory.
If you set the -npro flag, perltidy will not look for this file.
-pro=filename or --profile=filename
To simplify testing and switching .perltidyrc files, this command may be used to
specify a configuration file which will override the default name of .perltidyrc.
There must not be a space on either side of the '=' sign. For example, the line
perltidy -pro=testcfg
would cause file testcfg to be used instead of the default .perltidyrc.
A pathname begins with three dots, e.g. ".../.perltidyrc", indicates that the file
should be searched for starting in the current directory and working upwards. This
makes it easier to have multiple projects each with their own .perltidyrc in their
root directories.
-opt, --show-options
Write a list of all options used to the .LOG file. Please see --dump-options for a
simpler way to do this.
-f, --force-read-binary
Force perltidy to process binary files. To avoid producing excessive error messages,
perltidy skips files identified by the system as non-text. However, valid perl
scripts containing binary data may sometimes be identified as non-text, and this flag
forces perltidy to process them.
-ast, --assert-tidy
This flag asserts that the input and output code streams are identical, or in other
words that the input code is already 'tidy' according to the formatting parameters.
If this is not the case, an error message noting this is produced. This error message
will cause the process to return a non-zero exit code. The test for this is made by
comparing an MD5 hash value for the input and output code streams. This flag has no
other effect on the functioning of perltidy. This might be useful for certain code
maintenance operations. Note: you will not see this message if you have error
messages turned off with the -quiet flag.
-asu, --assert-untidy
This flag asserts that the input and output code streams are different, or in other
words that the input code is 'untidy' according to the formatting parameters. If this
is not the case, an error message noting this is produced. This flag has no other
effect on the functioning of perltidy.
FORMATTING OPTIONS
Basic Options
--notidy
This flag disables all formatting and causes the input to be copied unchanged to the
output except for possible changes in line ending characters and any pre- and post-
filters. This can be useful in conjunction with a hierarchical set of .perltidyrc
files to avoid unwanted code tidying. See also "Skipping Selected Sections of Code"
for a way to avoid tidying specific sections of code.
-i=n, --indent-columns=n
Use n columns per indentation level (default n=4).
-l=n, --maximum-line-length=n
The default maximum line length is n=80 characters. Perltidy will try to find line
break points to keep lines below this length. However, long quotes and side comments
may cause lines to exceed this length.
The default length of 80 comes from the past when this was the standard CRT screen
width. Many programmers prefer to increase this to something like 120.
Setting -l=0 is equivalent to setting -l=(a very large number). But this is not
recommended because, for example, a very long list will be formatted in a single long
line.
-vmll, --variable-maximum-line-length
A problem arises using a fixed maximum line length with very deeply nested code and
data structures because eventually the amount of leading whitespace used for
indicating indentation takes up most or all of the available line width, leaving
little or no space for the actual code or data. One solution is to use a very long
line length. Another solution is to use the -vmll flag, which basically tells
perltidy to ignore leading whitespace when measuring the line length.
To be precise, when the -vmll parameter is set, the maximum line length of a line of
code will be M+L*I, where
M is the value of --maximum-line-length=M (-l=M), default 80,
I is the value of --indent-columns=I (-i=I), default 4,
L is the indentation level of the line of code
When this flag is set, the choice of breakpoints for a block of code should be
essentially independent of its nesting depth. However, the absolute line lengths,
including leading whitespace, can still be arbitrarily large. This problem can be
avoided by including the next parameter.
The default is not to do this (-nvmll).
-wc=n, --whitespace-cycle=n
This flag also addresses problems with very deeply nested code and data structures.
When the nesting depth exceeds the value n the leading whitespace will be reduced and
start at a depth of 1 again. The result is that blocks of code will shift back to the
left rather than moving arbitrarily far to the right. This occurs cyclically to any
depth.
For example if one level of indentation equals 4 spaces (-i=4, the default), and one
uses -wc=15, then if the leading whitespace on a line exceeds about 4*15=60 spaces it
will be reduced back to 4*1=4 spaces and continue increasing from there. If the
whitespace never exceeds this limit the formatting remains unchanged.
The combination of -vmll and -wc=n provides a solution to the problem of displaying
arbitrarily deep data structures and code in a finite window, although -wc=n may of
course be used without -vmll.
The default is not to use this, which can also be indicated using -wc=0.
Tabs
Using tab characters will almost certainly lead to future portability and maintenance
problems, so the default and recommendation is not to use them. For those who prefer
tabs, however, there are two different options.
Except for possibly introducing tab indentation characters, as outlined below,
perltidy does not introduce any tab characters into your file, and it removes any tabs
from the code (unless requested not to do so with -fws). If you have any tabs in your
comments, quotes, or here-documents, they will remain.
-et=n, --entab-leading-whitespace
This flag causes each n leading space characters produced by the formatting
process to be replaced by one tab character. The formatting process itself works
with space characters. The -et=n parameter is applied as a last step, after
formatting is complete, to convert leading spaces into tabs. Before starting to
use tabs, it is essential to first get the indentation controls set as desired
without tabs, particularly the two parameters --indent-columns=n (or -i=n) and
--continuation-indentation=n (or -ci=n).
The value of the integer n can be any value but can be coordinated with the number
of spaces used for indentation. For example, -et=4 -ci=4 -i=4 will produce one tab
for each indentation level and and one for each continuation indentation level.
You may want to coordinate the value of n with what your display software assumes
for the spacing of a tab.
-t, --tabs
This flag causes one leading tab character to be inserted for each level of
indentation. Certain other features are incompatible with this option, and if
these options are also given, then a warning message will be issued and this flag
will be unset. One example is the -lp option. This flag is retained for backwards
compatibility, but if you use tabs, the -et=n flag is recommended. If both -t and
-et=n are set, the -et=n is used.
-dt=n, --default-tabsize=n
If the first line of code passed to perltidy contains leading tabs but no tab
scheme is specified for the output stream then perltidy must guess how many spaces
correspond to each leading tab. This number of spaces n corresponding to each
leading tab of the input stream may be specified with -dt=n. The default is n=8.
This flag has no effect if a tab scheme is specified for the output stream,
because then the input stream is assumed to use the same tab scheme and
indentation spaces as for the output stream (any other assumption would lead to
unstable editing).
-io, --indent-only
This flag is used to deactivate all whitespace and line break changes within non-blank
lines of code. When it is in effect, the only change to the script will be to the
indentation and to the number of blank lines. And any flags controlling whitespace
and newlines will be ignored. You might want to use this if you are perfectly happy
with your whitespace and line breaks, and merely want perltidy to handle the
indentation. (This also speeds up perltidy by well over a factor of two, so it might
be useful when perltidy is merely being used to help find a brace error in a large
script).
Setting this flag is equivalent to setting --freeze-newlines and --freeze-whitespace.
If you also want to keep your existing blank lines exactly as they are, you can add
--freeze-blank-lines.
With this option perltidy is still free to modify the indenting (and outdenting) of
code and comments as it normally would. If you also want to prevent long comment
lines from being outdented, you can add either -noll or -l=0.
Setting this flag will prevent perltidy from doing any special operations on closing
side comments. You may still delete all side comments however when this flag is in
effect.
-enc=s, --character-encoding=s
This flag indicates if the input data stream use a character encoding. Perltidy does
not look for the encoding directives in the source stream, such as use utf8, and
instead relies on this flag to determine the encoding. (Note that perltidy often
works on snippets of code rather than complete files so it cannot rely on use utf8
directives).
The possible values for s are:
-enc=none if no encoding is used, or
-enc=utf8 for encoding in utf8
-enc=guess if perltidy should guess between these two possibilities.
The value none causes the stream to be processed without special encoding assumptions.
This is appropriate for files which are written in single-byte character encodings
such as latin-1.
The value utf8 causes the stream to be read and written as UTF-8. If the input stream
cannot be decoded with this encoding then processing is not done.
The value guess tells perltidy to guess between either utf8 encoding or no encoding
(meaning one character per byte). The guess option uses the Encode::Guess module
which has been found to be reliable at detecting if a file is encoded in utf8 or not.
The current default is guess.
The abbreviations -utf8 or -UTF8 are equivalent to -enc=utf8, and the abbreviation
-guess is equivalent to -enc=guess. So to process a file named file.pl which is
encoded in UTF-8 you can use:
perltidy -utf8 file.pl
or
perltidy -guess file.pl
or simply
perltidy file.pl
since -guess is the default.
To process files with an encoding other than UTF-8, it would be necessary to write a
short program which calls the Perl::Tidy module with some pre- and post-processing to
handle decoding and encoding.
-eos=s, --encode-output-strings=s
This flag was added to resolve an issue involving the interface between Perl::Tidy and
calling programs, and in particular Code::TidyAll (tidyall).
If you only run the perltidy binary this flag has no effect. If you run a program
which calls the Perl::Tidy module and receives a string in return, then the meaning of
the flag is as follows:
• The setting -eos means Perl::Tidy should encode any string which it decodes. This
is the default because it makes perltidy behave well as a filter, and is the
correct setting for most programs.
• The setting -neos means that a string should remain decoded if it was decoded by
Perl::Tidy. This is only appropriate if the calling program will handle any
needed encoding before outputting the string.
The default was changed from -neos to -eos in versions after 20220217. If this change
causes a program to start running incorrectly on encoded files, an emergency fix might
be to set -neos. Additional information can be found in the man pages for the
Perl::Tidy module and also in
<https://github.com/perltidy/perltidy/blob/master/docs/eos_flag.md>.
-gcs, --use-unicode-gcstring
This flag controls whether or not perltidy may use module Unicode::GCString to obtain
accurate display widths of wide characters. The default is --nouse-unicode-gcstring.
If this flag is set, and text is encoded, perltidy will look for the module
Unicode::GCString and, if found, will use it to obtain character display widths. This
can improve displayed vertical alignment for files with wide characters. It is a nice
feature but it is off by default to avoid conflicting formatting when there are
multiple developers. Perltidy installation does not require Unicode::GCString, so
users wanting to use this feature need set this flag and also to install
Unicode::GCString separately.
If this flag is set and perltidy does not find module Unicode::GCString, a warning
message will be produced and processing will continue but without the potential
benefit provided by the module.
Also note that actual vertical alignment depends upon the fonts used by the text
display software, so vertical alignment may not be optimal even when Unicode::GCString
is used.
-ole=s, --output-line-ending=s
where s="win", "dos", "unix", or "mac". This flag tells perltidy to output line
endings for a specific system. Normally, perltidy writes files with the line
separator character of the host system. The "win" and "dos" flags have an identical
result.
-ple, --preserve-line-endings
This flag tells perltidy to write its output files with the same line endings as the
input file, if possible. It should work for dos, unix, and mac line endings. It will
only work if perltidy input comes from a filename (rather than stdin, for example).
If perltidy has trouble determining the input file line ending, it will revert to the
default behavior of using the line ending of the host system.
-atnl, --add-terminal-newline
This flag, which is enabled by default, allows perltidy to terminate the last line of
the output stream with a newline character, regardless of whether or not the input
stream was terminated with a newline character. If this flag is negated, with -natnl,
then perltidy will add a terminal newline to the the output stream only if the input
stream is terminated with a newline.
Negating this flag may be useful for manipulating one-line scripts intended for use on
a command line.
-it=n, --iterations=n
This flag causes perltidy to do n complete iterations. The reason for this flag is
that code beautification is an iterative process and in some cases the output from
perltidy can be different if it is applied a second time. For most purposes the
default of n=1 should be satisfactory. However n=2 can be useful when a major style
change is being made, or when code is being beautified on check-in to a source code
control system. It has been found to be extremely rare for the output to change after
2 iterations. If a value n is greater than 2 is input then a convergence test will be
used to stop the iterations as soon as possible, almost always after 2 iterations.
See the next item for a simplified iteration control.
This flag has no effect when perltidy is used to generate html.
-conv, --converge
This flag is equivalent to -it=4 and is included to simplify iteration control. For
all practical purposes one either does or does not want to be sure that the output is
converged, and there is no penalty to using a large iteration limit since perltidy
will check for convergence and stop iterating as soon as possible. The default is
-nconv (no convergence check). Using -conv will approximately double run time since
typically one extra iteration is required to verify convergence. No extra iterations
are required if no new line breaks are made, and two extra iterations are occasionally
needed when reformatting complex code structures, such as deeply nested ternary
statements.
Code Indentation Control
-ci=n, --continuation-indentation=n
Continuation indentation is extra indentation spaces applied when a long line is
broken. The default is n=2, illustrated here:
my $level = # -ci=2
( $max_index_to_go >= 0 ) ? $levels_to_go[0] : $last_output_level;
The same example, with n=0, is a little harder to read:
my $level = # -ci=0
( $max_index_to_go >= 0 ) ? $levels_to_go[0] : $last_output_level;
The value given to -ci is also used by some commands when a small space is required.
Examples are commands for outdenting labels, -ola, and control keywords, -okw.
When default values are not used, it is recommended that either
(1) the value n given with -ci=n be no more than about one-half of the number of
spaces assigned to a full indentation level on the -i=n command, or
(2) the flag -extended-continuation-indentation is used (see next section).
-xci, --extended-continuation-indentation
This flag allows perltidy to use some improvements which have been made to its
indentation model. One of the things it does is "extend" continuation indentation
deeper into structures, hence the name. The improved indentation is particularly
noticeable when the flags -ci=n and -i=n use the same value of n. There are no
significant disadvantages to using this flag, but to avoid disturbing existing
formatting the default is not to use it, -nxci.
Please see the section "-pbp, --perl-best-practices" for an example of how this flag
can improve the formatting of ternary statements. It can also improve indentation of
some multi-line qw lists as shown below.
# perltidy
foreach $color (
qw(
AntiqueWhite3 Bisque1 Bisque2 Bisque3 Bisque4
SlateBlue3 RoyalBlue1 SteelBlue2 DeepSkyBlue3
),
qw(
LightBlue1 DarkSlateGray1 Aquamarine2 DarkSeaGreen2
SeaGreen1 Yellow1 IndianRed1 IndianRed2 Tan1 Tan4
)
)
# perltidy -xci
foreach $color (
qw(
AntiqueWhite3 Bisque1 Bisque2 Bisque3 Bisque4
SlateBlue3 RoyalBlue1 SteelBlue2 DeepSkyBlue3
),
qw(
LightBlue1 DarkSlateGray1 Aquamarine2 DarkSeaGreen2
SeaGreen1 Yellow1 IndianRed1 IndianRed2 Tan1 Tan4
)
)
-sil=n --starting-indentation-level=n
By default, perltidy examines the input file and tries to determine the starting
indentation level. While it is often zero, it may not be zero for a code snippet
being sent from an editing session.
To guess the starting indentation level perltidy simply assumes that indentation
scheme used to create the code snippet is the same as is being used for the current
perltidy process. This is the only sensible guess that can be made. It should be
correct if this is true, but otherwise it probably won't. For example, if the input
script was written with -i=2 and the current perltidy flags have -i=4, the wrong
initial indentation will be guessed for a code snippet which has non-zero initial
indentation. Likewise, if an entabbing scheme is used in the input script and not in
the current process then the guessed indentation will be wrong.
If the default method does not work correctly, or you want to change the starting
level, use -sil=n, to force the starting level to be n.
List indentation using --line-up-parentheses, -lp or --extended--line-up-parentheses ,
-xlp
These flags provide an alternative indentation method for list data. The original
flag for this is -lp, but it has some limitations (explained below) which are avoided
with the newer -xlp flag. So -xlp is probably the better choice for new work, but the
-lp flag is retained to minimize changes to existing formatting. If you enter both
-lp and -xlp, then -xlp will be used.
In the default indentation method perltidy indents lists with 4 spaces, or whatever
value is specified with -i=n. Here is a small list formatted in this way:
# perltidy (default)
@month_of_year = (
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
);
The -lp or -xlp flags add extra indentation to cause the data to begin past the
opening parentheses of a sub call or list, or opening square bracket of an anonymous
array, or opening curly brace of an anonymous hash. With this option, the above list
would become:
# perltidy -lp or -xlp
@month_of_year = (
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
);
If the available line length (see -l=n ) does not permit this much space, perltidy
will use less. For alternate placement of the closing paren, see the next section.
These flags have no effect on code BLOCKS, such as if/then/else blocks, which always
use whatever is specified with -i=n.
Some limitations on these flags are:
• A limitation on -lp, but not -xlp, occurs in situations where perltidy does not
have complete freedom to choose line breaks. Then it may temporarily revert to its
default indentation method. This can occur for example if there are blank lines,
block comments, multi-line quotes, or side comments between the opening and
closing parens, braces, or brackets. It will also occur if a multi-line anonymous
sub occurs within a container since that will impose specific line breaks (such as
line breaks after statements).
• For both the -lp and -xlp flags, any parameter which significantly restricts the
ability of perltidy to choose newlines will conflict with these flags and will
cause them to be deactivated. These include -io, -fnl, -nanl, and -ndnl.
• The -lp and -xlp options may not be used together with the -t tabs option. They
may, however, be used with the -et=n tab method
There are some potential disadvantages of this indentation method compared to the
default method that should be noted:
• The available line length can quickly be used up if variable names are long. This
can cause deeply nested code to quickly reach the line length limit, and become
badly formatted, much sooner than would occur with the default indentation method.
• Since the indentation depends on the lengths of variable names, small changes in
variable names can cause changes in indentation over many lines in a file. This
means that minor name changes can produce significant file differences. This can
be annoying and does not occur with the default indentation method.
Some things that can be done to minimize these problems are:
• Increase --maximum-line-length=n above the default n=80 characters if necessary.
• If you use -xlp then long side comments can limit the indentation over multiple
lines. Consider adding the flag --ignore-side-comment-lengths to prevent this, or
minimizing the use of side comments.
• Apply this style in a limited way. By default, it applies to all list containers
(not just lists in parentheses). The next section describes how to limit this
style to, for example, just function calls. The default indentation method will
be applied elsewhere.
-lpil=s, --line-up-parentheses-inclusion-list and -lpxl=s,
--line-up-parentheses-exclusion-list
The following discussion is written for -lp but applies equally to the newer -xlp
version. By default, the -lp flag applies to as many containers as possible. The set
of containers to which the -lp style applies can be reduced by either one of these two
flags:
Use -lpil=s to specify the containers to which -lp applies, or
use -lpxl=s to specify the containers to which -lp does NOT apply.
Only one of these two flags may be used. Both flags can achieve the same result, but
the -lpil=s flag is much easier to describe and use and is recommended. The -lpxl=s
flag was the original implementation and is only retained for backwards compatibility.
This list s for these parameters is a string with space-separated items. Each item
consists of up to three pieces of information in this order: (1) an optional letter
code (2) a required container type, and (3) an optional numeric code.
The only required piece of information is a container type, which is one of '(', '[',
or '{'. For example the string
-lpil='('
means use -lp formatting only on lists within parentheses, not lists in square-
brackets or braces. The same thing could alternatively be specified with
-lpxl = '[ {'
which says to exclude lists within square-brackets and braces. So what remains is
lists within parentheses.
A second optional item of information which can be given for parentheses is an
alphanumeric letter which is used to limit the selection further depending on the type
of token immediately before the paren. The possible letters are currently 'k', 'K',
'f', 'F', 'w', and 'W', with these meanings for matching whatever precedes an opening
paren:
'k' matches if the previous nonblank token is a perl built-in keyword (such as 'if', 'while'),
'K' matches if 'k' does not, meaning that the previous token is not a keyword.
'f' matches if the previous token is a function other than a keyword.
'F' matches if 'f' does not.
'w' matches if either 'k' or 'f' match.
'W' matches if 'w' does not.
For example:
-lpil = 'f('
means only apply -lp to function calls, and
-lpil = 'w('
means only apply -lp to parenthesized lists which follow a function or a keyword.
This last example could alternatively be written using the -lpxl=s flag as
-lpxl = '[ { W('
which says exclude -lp for lists within square-brackets, braces, and parens NOT
preceded by a keyword or function. Clearly, the -lpil=s method is easier to
understand.
An optional numeric code may follow any of the container types to further refine the
selection based on container contents. The numeric codes are:
'0' or blank: no check on contents is made
'1' exclude B<-lp> unless the contents is a simple list without sublists
'2' exclude B<-lp> unless the contents is a simple list without sublists, without
code blocks, and without ternary operators
For example,
-lpil = 'f(2'
means only apply -lp to function call lists which do not contain any sublists, code
blocks or ternary expressions.
-cti=n, --closing-token-indentation
The -cti=n flag controls the indentation of a line beginning with a ")", "]", or a
non-block "}". Such a line receives:
-cti = 0 no extra indentation (default)
-cti = 1 extra indentation such that the closing token
aligns with its opening token.
-cti = 2 one extra indentation level if the line looks like:
); or ]; or };
-cti = 3 one extra indentation level always
The flags -cti=1 and -cti=2 work well with the -lp flag (previous section).
# perltidy -lp -cti=1
@month_of_year = (
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
);
# perltidy -lp -cti=2
@month_of_year = (
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
);
These flags are merely hints to the formatter and they may not always be followed. In
particular, if -lp is not being used, the indentation for cti=1 is constrained to be
no more than one indentation level.
If desired, this control can be applied independently to each of the closing container
token types. In fact, -cti=n is merely an abbreviation for -cpi=n -csbi=n -cbi=n,
where: -cpi or --closing-paren-indentation controls )'s, -csbi or
--closing-square-bracket-indentation controls ]'s, -cbi or --closing-brace-indentation
controls non-block }'s.
-icp, --indent-closing-paren
The -icp flag is equivalent to -cti=2, described in the previous section. The -nicp
flag is equivalent -cti=0. They are included for backwards compatibility.
-icb, --indent-closing-brace
The -icb option gives one extra level of indentation to a brace which terminates a
code block . For example,
if ($task) {
yyy();
} # -icb
else {
zzz();
}
The default is not to do this, indicated by -nicb.
-nib, --non-indenting-braces
Normally, lines of code contained within a pair of block braces receive one additional
level of indentation. This flag, which is enabled by default, causes perltidy to look
for opening block braces which are followed by a special side comment. This special
side comment is #<<< by default. If found, the code between this opening brace and
its corresponding closing brace will not be given the normal extra indentation level.
For example:
{ #<<< a closure to contain lexical vars
my $var; # this line does not get one level of indentation
...
}
# this line does not 'see' $var;
This can be useful, for example, when combining code from different files. Different
sections of code can be placed within braces to keep their lexical variables from
being visible to the end of the file. To keep the new braces from causing all of
their contained code to be indented if you run perltidy, and possibly introducing new
line breaks in long lines, you can mark the opening braces with this special side
comment.
Only the opening brace needs to be marked, since perltidy knows where the closing
brace is. Braces contained within marked braces may also be marked as non-indenting.
If your code happens to have some opening braces followed by '#<<<', and you don't
want this behavior, you can use -nnib to deactivate it. To make it easy to remember,
the default string is the same as the string for starting a format-skipping section.
There is no confusion because in that case it is for a block comment rather than a
side-comment.
The special side comment can be changed with the next parameter.
-nibp=s, --non-indenting-brace-prefix=s
The -nibp=string parameter may be used to change the marker for non-indenting braces.
The default is equivalent to -nibp='#<<<'. The string that you enter must begin with
a # and should be in quotes as necessary to get past the command shell of your system.
This string is the leading text of a regex pattern that is constructed by appending
pre-pending a '^' and appending a'\s', so you must also include backslashes for
characters to be taken literally rather than as patterns.
For example, to match the side comment '#++', the parameter would be
-nibp='#\+\+'
-olq, --outdent-long-quotes
When -olq is set, lines which is a quoted string longer than the value maximum-line-
length will have their indentation removed to make them more readable. This is the
default. To prevent such out-denting, use -nolq or --nooutdent-long-lines.
-oll, --outdent-long-lines
This command is equivalent to --outdent-long-quotes and --outdent-long-comments, and
it is included for compatibility with previous versions of perltidy. The negation of
this also works, -noll or --nooutdent-long-lines, and is equivalent to setting -nolq
and -nolc.
Outdenting Labels: -ola, --outdent-labels
This command will cause labels to be outdented by 2 spaces (or whatever -ci has been
set to), if possible. This is the default. For example:
my $i;
LOOP: while ( $i = <FOTOS> ) {
chomp($i);
next unless $i;
fixit($i);
}
Use -nola to not outdent labels. To control line breaks after labels see "-bal=n,
--break-after-labels=n".
Outdenting Keywords
-okw, --outdent-keywords
The command -okw will cause certain leading control keywords to be outdented by 2
spaces (or whatever -ci has been set to), if possible. By default, these keywords
are "redo", "next", "last", "goto", and "return". The intention is to make these
control keywords easier to see. To change this list of keywords being outdented,
see the next section.
For example, using "perltidy -okw" on the previous example gives:
my $i;
LOOP: while ( $i = <FOTOS> ) {
chomp($i);
next unless $i;
fixit($i);
}
The default is not to do this.
Specifying Outdented Keywords: -okwl=string, --outdent-keyword-list=string
This command can be used to change the keywords which are outdented with the -okw
command. The parameter string is a required list of perl keywords, which should
be placed in quotes if there are more than one. By itself, it does not cause any
outdenting to occur, so the -okw command is still required.
For example, the commands "-okwl="next last redo goto" -okw" will cause those four
keywords to be outdented. It is probably simplest to place any -okwl command in a
.perltidyrc file.
Whitespace Control
Whitespace refers to the blank space between variables, operators, and other code tokens.
-fws, --freeze-whitespace
This flag causes your original whitespace to remain unchanged, and causes the rest of
the whitespace commands in this section, the Code Indentation section, and the Comment
Control section to be ignored.
Tightness of curly braces, parentheses, and square brackets
Here the term "tightness" will mean the closeness with which pairs of enclosing
tokens, such as parentheses, contain the quantities within. A numerical value of 0,
1, or 2 defines the tightness, with 0 being least tight and 2 being most tight.
Spaces within containers are always symmetric, so if there is a space after a "(" then
there will be a space before the corresponding ")".
The -pt=n or --paren-tightness=n parameter controls the space within parens. The
example below shows the effect of the three possible values, 0, 1, and 2:
if ( ( my $len_tab = length( $tabstr ) ) > 0 ) { # -pt=0
if ( ( my $len_tab = length($tabstr) ) > 0 ) { # -pt=1 (default)
if ((my $len_tab = length($tabstr)) > 0) { # -pt=2
When n is 0, there is always a space to the right of a '(' and to the left of a ')'.
For n=2 there is never a space. For n=1, the default, there is a space unless the
quantity within the parens is a single token, such as an identifier or quoted string.
Likewise, the parameter -sbt=n or --square-bracket-tightness=n controls the space
within square brackets, as illustrated below.
$width = $col[ $j + $k ] - $col[ $j ]; # -sbt=0
$width = $col[ $j + $k ] - $col[$j]; # -sbt=1 (default)
$width = $col[$j + $k] - $col[$j]; # -sbt=2
Curly braces which do not contain code blocks are controlled by the parameter -bt=n or
--brace-tightness=n.
$obj->{ $parsed_sql->{ 'table' }[0] }; # -bt=0
$obj->{ $parsed_sql->{'table'}[0] }; # -bt=1 (default)
$obj->{$parsed_sql->{'table'}[0]}; # -bt=2
And finally, curly braces which contain blocks of code are controlled by the parameter
-bbt=n or --block-brace-tightness=n as illustrated in the example below.
%bf = map { $_ => -M $_ } grep { /\.deb$/ } dirents '.'; # -bbt=0 (default)
%bf = map { $_ => -M $_ } grep {/\.deb$/} dirents '.'; # -bbt=1
%bf = map {$_ => -M $_} grep {/\.deb$/} dirents '.'; # -bbt=2
To simplify input in the case that all of the tightness flags have the same value <n>,
the parameter <-act=n> or --all-containers-tightness=n is an abbreviation for the
combination <-pt=n -sbt=n -bt=n -bbt=n>.
-tso, --tight-secret-operators
The flag -tso causes certain perl token sequences (secret operators) which might be
considered to be a single operator to be formatted "tightly" (without spaces). The
operators currently modified by this flag are:
0+ +0 ()x!! ~~<> ,=> =( )=
For example the sequence 0 +, which converts a string to a number, would be formatted
without a space: 0+ when the -tso flag is set. This flag is off by default.
-sts, --space-terminal-semicolon
Some programmers prefer a space before all terminal semicolons. The default is for no
such space, and is indicated with -nsts or --nospace-terminal-semicolon.
$i = 1 ; # -sts
$i = 1; # -nsts (default)
-sfs, --space-for-semicolon
Semicolons within for loops may sometimes be hard to see, particularly when commas are
also present. This option places spaces on both sides of these special semicolons,
and is the default. Use -nsfs or --nospace-for-semicolon to deactivate it.
for ( @a = @$ap, $u = shift @a ; @a ; $u = $v ) { # -sfs (default)
for ( @a = @$ap, $u = shift @a; @a; $u = $v ) { # -nsfs
-asc, --add-semicolons
Setting -asc allows perltidy to add any missing optional semicolon at the end of a
line which is followed by a closing curly brace on the next line. This is the
default, and may be deactivated with -nasc or --noadd-semicolons.
-dsm, --delete-semicolons
Setting -dsm allows perltidy to delete extra semicolons which are simply empty
statements. This is the default, and may be deactivated with -ndsm or
--nodelete-semicolons. (Such semicolons are not deleted, however, if they would
promote a side comment to a block comment).
-aws, --add-whitespace
Setting this option allows perltidy to add certain whitespace to improve code
readability. This is the default. If you do not want any whitespace added, but are
willing to have some whitespace deleted, use -naws. (Use -fws to leave whitespace
completely unchanged).
-dws, --delete-old-whitespace
Setting this option allows perltidy to remove some old whitespace between characters,
if necessary. This is the default. If you do not want any old whitespace removed,
use -ndws or --nodelete-old-whitespace.
Detailed whitespace controls around tokens
For those who want more detailed control over the whitespace around tokens, there are
four parameters which can directly modify the default whitespace rules built into
perltidy for any token. They are:
-wls=s or --want-left-space=s,
-nwls=s or --nowant-left-space=s,
-wrs=s or --want-right-space=s,
-nwrs=s or --nowant-right-space=s.
These parameters are each followed by a quoted string, s, containing a list of token
types. No more than one of each of these parameters should be specified, because
repeating a command-line parameter always overwrites the previous one before perltidy
ever sees it.
To illustrate how these are used, suppose it is desired that there be no space on
either side of the token types = + - / *. The following two parameters would specify
this desire:
-nwls="= + - / *" -nwrs="= + - / *"
(Note that the token types are in quotes, and that they are separated by spaces).
With these modified whitespace rules, the following line of math:
$root = -$b + sqrt( $b * $b - 4. * $a * $c ) / ( 2. * $a );
becomes this:
$root=-$b+sqrt( $b*$b-4.*$a*$c )/( 2.*$a );
These parameters should be considered to be hints to perltidy rather than fixed rules,
because perltidy must try to resolve conflicts that arise between them and all of the
other rules that it uses. One conflict that can arise is if, between two tokens, the
left token wants a space and the right one doesn't. In this case, the token not
wanting a space takes priority.
It is necessary to have a list of all token types in order to create this type of
input. Such a list can be obtained by the command --dump-token-types. Also try the
-D flag on a short snippet of code and look at the .DEBUG file to see the
tokenization.
WARNING Be sure to put these tokens in quotes to avoid having them misinterpreted by
your command shell.
Note1: Perltidy does always follow whitespace controls
The various parameters controlling whitespace within a program are requests which
perltidy follows as well as possible, but there are a number of situations where
changing whitespace could change program behavior and is not done. Some of these are
obvious; for example, we should not remove the space between the two plus symbols in
'$x+ +$y' to avoid creating a '++' operator. Some are more subtle and involve the
whitespace around bareword symbols and locations of possible filehandles. For
example, consider the problem of formatting the following subroutine:
sub print_div {
my ($x,$y)=@_;
print $x/$y;
}
Suppose the user requests that / signs have a space to the left but not to the right.
Perltidy will refuse to do this, but if this were done the result would be
sub print_div {
my ($x,$y)=@_;
print $x /$y;
}
If formatted in this way, the program will not run (at least with recent versions of
perl) because the $x is taken to be a filehandle and / is assumed to start a quote. In
a complex program, there might happen to be a / which terminates the multiline quote
without a syntax error, allowing the program to run, but not as intended.
Related issues arise with other binary operator symbols, such as + and -, and in older
versions of perl there could be problems with ternary operators. So to avoid changing
program behavior, perltidy has the simple rule that whitespace around possible
filehandles is left unchanged. Likewise, whitespace around barewords is left
unchanged. The reason is that if the barewords are defined in other modules, or in
code that has not even been written yet, perltidy will not have seen their prototypes
and must treat them cautiously.
In perltidy this is implemented in the tokenizer by marking token following a print
keyword as a special type Z. When formatting is being done, whitespace following this
token type is generally left unchanged as a precaution against changing program
behavior. This is excessively conservative but simple and easy to implement.
Keywords which are treated similarly to print include printf, sort, exec, system.
Changes in spacing around parameters following these keywords may have to be made
manually. For example, the space, or lack of space, after the parameter $foo in the
following line will be unchanged in formatting.
system($foo );
system($foo);
To find if a token is of type Z you can use perltidy -DEBUG. For the first line above
the result is
1: system($foo );
1: kkkkkk{ZZZZb};
which shows that system is type k (keyword) and $foo is type Z.
Note2: Perltidy's whitespace rules are not perfect
Despite these precautions, it is still possible to introduce syntax errors with some
asymmetric whitespace rules, particularly when call parameters are not placed in
containing parens or braces. For example, the following two lines will be parsed by
perl without a syntax error:
# original programming, syntax ok
my @newkeys = map $_-$nrecs+@data, @oldkeys;
# perltidy default, syntax ok
my @newkeys = map $_ - $nrecs + @data, @oldkeys;
But the following will give a syntax error:
# perltidy -nwrs='-'
my @newkeys = map $_ -$nrecs + @data, @oldkeys;
For another example, the following two lines will be parsed without syntax error:
# original programming, syntax ok
for my $severity ( reverse $SEVERITY_LOWEST+1 .. $SEVERITY_HIGHEST ) { ... }
# perltidy default, syntax ok
for my $severity ( reverse $SEVERITY_LOWEST + 1 .. $SEVERITY_HIGHEST ) { ... }
But the following will give a syntax error:
# perltidy -nwrs='+', syntax error:
for my $severity ( reverse $SEVERITY_LOWEST +1 .. $SEVERITY_HIGHEST ) { ... }
To avoid subtle parsing problems like this, it is best to avoid spacing a binary
operator asymmetrically with a space on the left but not on the right.
Space between specific keywords and opening paren
When an opening paren follows a Perl keyword, no space is introduced after the
keyword, unless it is (by default) one of these:
my local our and or xor eq ne if else elsif until unless
while for foreach return switch case given when
These defaults can be modified with two commands:
-sak=s or --space-after-keyword=s adds keywords.
-nsak=s or --nospace-after-keyword=s removes keywords.
where s is a list of keywords (in quotes if necessary). For example,
my ( $a, $b, $c ) = @_; # default
my( $a, $b, $c ) = @_; # -nsak="my local our"
The abbreviation -nsak='*' is equivalent to including all of the keywords in the above
list.
When both -nsak=s and -sak=s commands are included, the -nsak=s command is executed
first. For example, to have space after only the keywords (my, local, our) you could
use -nsak="*" -sak="my local our".
To put a space after all keywords, see the next item.
Space between all keywords and opening parens
When an opening paren follows a function or keyword, no space is introduced after the
keyword except for the keywords noted in the previous item. To always put a space
between a function or keyword and its opening paren, use the command:
-skp or --space-keyword-paren
You may also want to use the flag -sfp (next item) too.
Space between all function names and opening parens
When an opening paren follows a function the default and recommended formatting is not
to introduce a space. To cause a space to be introduced use:
-sfp or --space-function-paren
myfunc( $a, $b, $c ); # default
myfunc ( $a, $b, $c ); # -sfp
You will probably also want to use the flag -skp (previous item) too.
The parameter is not recommended because spacing a function paren can make a program
vulnerable to parsing problems by Perl. For example, the following two-line program
will run as written but will have a syntax error if reformatted with -sfp:
if ( -e filename() ) { print "I'm here\n"; }
sub filename { return $0 }
In this particular case the syntax error can be removed if the line order is reversed,
so that Perl parses 'sub filename' first.
-fpva or --function-paren-vertical-alignment
A side-effect of using the -sfp flag is that the parens may become vertically aligned.
For example,
# perltidy -sfp
myfun ( $aaa, $b, $cc );
mylongfun ( $a, $b, $c );
This is the default behavior. To prevent this alignment use -nfpva:
# perltidy -sfp -nfpva
myfun ( $aaa, $b, $cc );
mylongfun ( $a, $b, $c );
-spp=n or --space-prototype-paren=n
This flag can be used to control whether a function prototype is preceded by a space.
For example, the following prototype does not have a space.
sub usage();
This integer n may have the value 0, 1, or 2 as follows:
-spp=0 means no space before the paren
-spp=1 means follow the example of the source code [DEFAULT]
-spp=2 means always put a space before the paren
The default is -spp=1, meaning that a space will be used if and only if there is one
in the source code. Given the above line of code, the result of applying the
different options would be:
sub usage(); # n=0 [no space]
sub usage(); # n=1 [default; follows input]
sub usage (); # n=2 [space]
-kpit=n or --keyword-paren-inner-tightness=n
The space inside of an opening paren, which itself follows a certain keyword, can be
controlled by this parameter. The space on the inside of the corresponding closing
paren will be treated in the same (balanced) manner. This parameter has precedence
over any other paren spacing rules. The values of n are as follows:
-kpit=0 means always put a space (not tight)
-kpit=1 means ignore this parameter [default]
-kpit=2 means never put a space (tight)
To illustrate, the following snippet is shown formatted in three ways:
if ( seek( DATA, 0, 0 ) ) { ... } # perltidy (default)
if (seek(DATA, 0, 0)) { ... } # perltidy -pt=2
if ( seek(DATA, 0, 0) ) { ... } # perltidy -pt=2 -kpit=0
In the second case the -pt=2 parameter makes all of the parens tight. In the third
case the -kpit=0 flag causes the space within the 'if' parens to have a space, since
'if' is one of the keywords to which the -kpit flag applies by default. The remaining
parens are still tight because of the -pt=2 parameter.
The set of keywords to which this parameter applies are by default are:
if elsif unless while until for foreach
These can be changed with the parameter -kpitl=s described in the next section.
-kpitl=string or --keyword-paren-inner-tightness=string
This command can be used to change the keywords to which the the -kpit=n command
applies. The parameter string is a required list either keywords or functions, which
should be placed in quotes if there are more than one. By itself, this parameter does
not cause any change in spacing, so the -kpit=n command is still required.
For example, the commands "-kpitl="if else while" -kpit=2" will cause the just the
spaces inside parens following 'if', 'else', and 'while' keywords to follow the
tightness value indicated by the -kpit=2 flag.
-lop or --logical-padding
In the following example some extra space has been inserted on the second line between
the two open parens. This extra space is called "logical padding" and is intended to
help align similar things vertically in some logical or ternary expressions.
# perltidy [default formatting]
$same =
( ( $aP eq $bP )
&& ( $aS eq $bS )
&& ( $aT eq $bT )
&& ( $a->{'title'} eq $b->{'title'} )
&& ( $a->{'href'} eq $b->{'href'} ) );
Note that this is considered to be a different operation from "vertical alignment"
because space at just one line is being adjusted, whereas in "vertical alignment" the
spaces at all lines are being adjusted. So it sort of a local version of vertical
alignment.
Here is an example involving a ternary operator:
# perltidy [default formatting]
$bits =
$top > 0xffff ? 32
: $top > 0xff ? 16
: $top > 1 ? 8
: 1;
This behavior is controlled with the flag --logical-padding, which is set 'on' by
default. If it is not desired it can be turned off using --nological-padding or
-nlop. The above two examples become, with -nlop:
# perltidy -nlop
$same =
( ( $aP eq $bP )
&& ( $aS eq $bS )
&& ( $aT eq $bT )
&& ( $a->{'title'} eq $b->{'title'} )
&& ( $a->{'href'} eq $b->{'href'} ) );
# perltidy -nlop
$bits =
$top > 0xffff ? 32
: $top > 0xff ? 16
: $top > 1 ? 8
: 1;
Trimming whitespace around "qw" quotes
-tqw or --trim-qw provide the default behavior of trimming spaces around multi-line
"qw" quotes and indenting them appropriately.
-ntqw or --notrim-qw cause leading and trailing whitespace around multi-line "qw"
quotes to be left unchanged. This option will not normally be necessary, but was
added for testing purposes, because in some versions of perl, trimming "qw" quotes
changes the syntax tree.
-sbq=n or --space-backslash-quote=n
lines like
$str1=\"string1";
$str2=\'string2';
can confuse syntax highlighters unless a space is included between the backslash and
the single or double quotation mark.
this can be controlled with the value of n as follows:
-sbq=0 means no space between the backslash and quote
-sbq=1 means follow the example of the source code
-sbq=2 means always put a space between the backslash and quote
The default is -sbq=1, meaning that a space will be used if there is one in the source
code.
Trimming trailing whitespace from lines of POD
-trp or --trim-pod will remove trailing whitespace from lines of POD. The default is
not to do this.
Comment Controls
Perltidy has a number of ways to control the appearance of both block comments and side
comments. The term block comment here refers to a full-line comment, whereas side comment
will refer to a comment which appears on a line to the right of some code.
-ibc, --indent-block-comments
Block comments normally look best when they are indented to the same level as the code
which follows them. This is the default behavior, but you may use -nibc to keep block
comments left-justified. Here is an example:
# this comment is indented (-ibc, default)
if ($task) { yyy(); }
The alternative is -nibc:
# this comment is not indented (-nibc)
if ($task) { yyy(); }
See also the next item, -isbc, as well as -sbc, for other ways to have some indented
and some outdented block comments.
-isbc, --indent-spaced-block-comments
If there is no leading space on the line, then the comment will not be indented, and
otherwise it may be.
If both -ibc and -isbc are set, then -isbc takes priority.
-olc, --outdent-long-comments
When -olc is set, lines which are full-line (block) comments longer than the value
maximum-line-length will have their indentation removed. This is the default; use
-nolc to prevent outdenting.
-msc=n, --minimum-space-to-comment=n
Side comments look best when lined up several spaces to the right of code. Perltidy
will try to keep comments at least n spaces to the right. The default is n=4 spaces.
-fpsc=n, --fixed-position-side-comment=n
This parameter tells perltidy to line up side comments in column number n whenever
possible. The default, n=0, will not do this.
-iscl, --ignore-side-comment-lengths
This parameter causes perltidy to ignore the length of side comments when setting line
breaks. The default, -niscl, is to include the length of side comments when breaking
lines to stay within the length prescribed by the -l=n maximum line length parameter.
For example, the following long single line would remain intact with -l=80 and -iscl:
perltidy -l=80 -iscl
$vmsfile =~ s/;[\d\-]*$//; # Clip off version number; we can use a newer version as well
whereas without the -iscl flag the line will be broken:
perltidy -l=80
$vmsfile =~ s/;[\d\-]*$//
; # Clip off version number; we can use a newer version as well
-hsc, --hanging-side-comments
By default, perltidy tries to identify and align "hanging side comments", which are
something like this:
my $IGNORE = 0; # This is a side comment
# This is a hanging side comment
# And so is this
A comment is considered to be a hanging side comment if (1) it immediately follows a
line with a side comment, or another hanging side comment, and (2) there is some
leading whitespace on the line. To deactivate this feature, use -nhsc or
--nohanging-side-comments. If block comments are preceded by a blank line, or have no
leading whitespace, they will not be mistaken as hanging side comments.
Closing Side Comments
A closing side comment is a special comment which perltidy can automatically create
and place after the closing brace of a code block. They can be useful for code
maintenance and debugging. The command -csc (or --closing-side-comments) adds or
updates closing side comments. For example, here is a small code snippet
sub message {
if ( !defined( $_[0] ) ) {
print("Hello, World\n");
}
else {
print( $_[0], "\n" );
}
}
And here is the result of processing with "perltidy -csc":
sub message {
if ( !defined( $_[0] ) ) {
print("Hello, World\n");
}
else {
print( $_[0], "\n" );
}
} ## end sub message
A closing side comment was added for "sub message" in this case, but not for the "if"
and "else" blocks, because they were below the 6 line cutoff limit for adding closing
side comments. This limit may be changed with the -csci command, described below.
The command -dcsc (or --delete-closing-side-comments) reverses this process and
removes these comments.
Several commands are available to modify the behavior of these two basic commands,
-csc and -dcsc:
-csci=n, or --closing-side-comment-interval=n
where "n" is the minimum number of lines that a block must have in order for a
closing side comment to be added. The default value is "n=6". To illustrate:
# perltidy -csci=2 -csc
sub message {
if ( !defined( $_[0] ) ) {
print("Hello, World\n");
} ## end if ( !defined( $_[0] ))
else {
print( $_[0], "\n" );
} ## end else [ if ( !defined( $_[0] ))
} ## end sub message
Now the "if" and "else" blocks are commented. However, now this has become very
cluttered.
-cscp=string, or --closing-side-comment-prefix=string
where string is the prefix used before the name of the block type. The default
prefix, shown above, is "## end". This string will be added to closing side
comments, and it will also be used to recognize them in order to update, delete,
and format them. Any comment identified as a closing side comment will be placed
just a single space to the right of its closing brace.
-cscl=string, or --closing-side-comment-list
where "string" is a list of block types to be tagged with closing side comments.
By default, all code block types preceded by a keyword or label (such as "if",
"sub", and so on) will be tagged. The -cscl command changes the default list to
be any selected block types; see "Specifying Block Types". For example, the
following command requests that only "sub"'s, labels, "BEGIN", and "END" blocks be
affected by any -csc or -dcsc operation:
-cscl="sub : BEGIN END"
-csct=n, or --closing-side-comment-maximum-text=n
The text appended to certain block types, such as an "if" block, is whatever lies
between the keyword introducing the block, such as "if", and the opening brace.
Since this might be too much text for a side comment, there needs to be a limit,
and that is the purpose of this parameter. The default value is "n=20", meaning
that no additional tokens will be appended to this text after its length reaches
20 characters. Omitted text is indicated with "...". (Tokens, including sub
names, are never truncated, however, so actual lengths may exceed this). To
illustrate, in the above example, the appended text of the first block is " (
!defined( $_[0] )...". The existing limit of "n=20" caused this text to be
truncated, as indicated by the "...". See the next flag for additional control of
the abbreviated text.
-cscb, or --closing-side-comments-balanced
As discussed in the previous item, when the closing-side-comment-maximum-text
limit is exceeded the comment text must be truncated. Older versions of perltidy
terminated with three dots, and this can still be achieved with -ncscb:
perltidy -csc -ncscb
} ## end foreach my $foo (sort { $b cmp $a ...
However this causes a problem with editors which cannot recognize comments or are
not configured to do so because they cannot "bounce" around in the text correctly.
The -cscb flag has been added to help them by appending appropriate balancing
structure:
perltidy -csc -cscb
} ## end foreach my $foo (sort { $b cmp $a ... })
The default is -cscb.
-csce=n, or --closing-side-comment-else-flag=n
The default, n=0, places the text of the opening "if" statement after any terminal
"else".
If n=2 is used, then each "elsif" is also given the text of the opening "if"
statement. Also, an "else" will include the text of a preceding "elsif"
statement. Note that this may result some long closing side comments.
If n=1 is used, the results will be the same as n=2 whenever the resulting line
length is less than the maximum allowed.
-cscb, or --closing-side-comments-balanced
When using closing-side-comments, and the closing-side-comment-maximum-text limit
is exceeded, then the comment text must be abbreviated. It is terminated with
three dots if the -cscb flag is negated:
perltidy -csc -ncscb
} ## end foreach my $foo (sort { $b cmp $a ...
This causes a problem with older editors which do not recognize comments because
they cannot "bounce" around in the text correctly. The -cscb flag tries to help
them by appending appropriate terminal balancing structures:
perltidy -csc -cscb
} ## end foreach my $foo (sort { $b cmp $a ... })
The default is -cscb.
-cscw, or --closing-side-comment-warnings
This parameter is intended to help make the initial transition to the use of
closing side comments. It causes two things to happen if a closing side comment
replaces an existing, different closing side comment: first, an error message
will be issued, and second, the original side comment will be placed alone on a
new specially marked comment line for later attention.
The intent is to avoid clobbering existing hand-written side comments which happen
to match the pattern of closing side comments. This flag should only be needed on
the first run with -csc.
Important Notes on Closing Side Comments:
• Closing side comments are only placed on lines terminated with a closing brace.
Certain closing styles, such as the use of cuddled elses (-ce), preclude the
generation of some closing side comments.
• Please note that adding or deleting of closing side comments takes place only
through the commands -csc or -dcsc. The other commands, if used, merely modify
the behavior of these two commands.
• It is recommended that the -cscw flag be used along with -csc on the first use of
perltidy on a given file. This will prevent loss of any existing side comment
data which happens to have the csc prefix.
• Once you use -csc, you should continue to use it so that any closing side comments
remain correct as code changes. Otherwise, these comments will become incorrect
as the code is updated.
• If you edit the closing side comments generated by perltidy, you must also change
the prefix to be different from the closing side comment prefix. Otherwise, your
edits will be lost when you rerun perltidy with -csc. For example, you could
simply change "## end" to be "## End", since the test is case sensitive. You may
also want to use the -ssc flag to keep these modified closing side comments spaced
the same as actual closing side comments.
• Temporarily generating closing side comments is a useful technique for exploring
and/or debugging a perl script, especially one written by someone else. You can
always remove them with -dcsc.
Static Block Comments
Static block comments are block comments with a special leading pattern, "##" by
default, which will be treated slightly differently from other block comments. They
effectively behave as if they had glue along their left and top edges, because they
stick to the left edge and previous line when there is no blank spaces in those
places. This option is particularly useful for controlling how commented code is
displayed.
-sbc, --static-block-comments
When -sbc is used, a block comment with a special leading pattern, "##" by
default, will be treated specially.
Comments so identified are treated as follows:
• If there is no leading space on the line, then the comment will not be
indented, and otherwise it may be,
• no new blank line will be inserted before such a comment, and
• such a comment will never become a hanging side comment.
For example, assuming @month_of_year is left-adjusted:
@month_of_year = ( # -sbc (default)
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
## 'Dec', 'Nov'
'Nov', 'Dec');
Without this convention, the above code would become
@month_of_year = ( # -nsbc
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
## 'Dec', 'Nov'
'Nov', 'Dec'
);
which is not as clear. The default is to use -sbc. This may be deactivated with
-nsbc.
-sbcp=string, --static-block-comment-prefix=string
This parameter defines the prefix used to identify static block comments when the
-sbc parameter is set. The default prefix is "##", corresponding to "-sbcp=##".
The prefix is actually part of a perl pattern used to match lines and it must
either begin with "#" or "^#". In the first case a prefix ^\s* will be added to
match any leading whitespace, while in the second case the pattern will match only
comments with no leading whitespace. For example, to identify all comments as
static block comments, one would use "-sbcp=#". To identify all left-adjusted
comments as static block comments, use "-sbcp='^#'".
Please note that -sbcp merely defines the pattern used to identify static block
comments; it will not be used unless the switch -sbc is set. Also, please be
aware that since this string is used in a perl regular expression which identifies
these comments, it must enable a valid regular expression to be formed.
A pattern which can be useful is:
-sbcp=^#{2,}[^\s#]
This pattern requires a static block comment to have at least one character which
is neither a # nor a space. It allows a line containing only '#' characters to be
rejected as a static block comment. Such lines are often used at the start and
end of header information in subroutines and should not be separated from the
intervening comments, which typically begin with just a single '#'.
-osbc, --outdent-static-block-comments
The command -osbc will cause static block comments to be outdented by 2 spaces (or
whatever -ci=n has been set to), if possible.
Static Side Comments
Static side comments are side comments with a special leading pattern. This option
can be useful for controlling how commented code is displayed when it is a side
comment.
-ssc, --static-side-comments
When -ssc is used, a side comment with a static leading pattern, which is "##" by
default, will be spaced only a single space from previous character, and it will
not be vertically aligned with other side comments.
The default is -nssc.
-sscp=string, --static-side-comment-prefix=string
This parameter defines the prefix used to identify static side comments when the
-ssc parameter is set. The default prefix is "##", corresponding to "-sscp=##".
Please note that -sscp merely defines the pattern used to identify static side
comments; it will not be used unless the switch -ssc is set. Also, note that this
string is used in a perl regular expression which identifies these comments, so it
must enable a valid regular expression to be formed.
Skipping Selected Sections of Code
Selected lines of code may be passed verbatim to the output without any formatting by
marking the starting and ending lines with special comments. There are two options for
doing this. The first option is called --format-skipping or -fs, and the second option is
called --code-skipping or -cs.
In both cases the lines of code will be output without any changes. The difference is
that in --format-skipping perltidy will still parse the marked lines of code and check for
errors, whereas in --code-skipping perltidy will simply pass the lines to the output
without any checking.
Both of these features are enabled by default and are invoked with special comment
markers. --format-skipping uses starting and ending markers '#<<<' and '#>>>', like this:
#<<< format skipping: do not let perltidy change my nice formatting
my @list = (1,
1, 1,
1, 2, 1,
1, 3, 3, 1,
1, 4, 6, 4, 1,);
#>>>
--code-skipping uses starting and ending markers '#<<V' and '#>>V', like this:
#<<V code skipping: perltidy will pass this verbatim without error checking
token ident_digit {
[ [ <?word> | _ | <?digit> ] <?ident_digit>
| <''>
]
};
#>>V
Additional text may appear on the special comment lines provided that it is separated from
the marker by at least one space, as in the above examples.
Any number of code-skipping or format-skipping sections may appear in a file. If an
opening code-skipping or format-skipping comment is not followed by a corresponding
closing comment, then skipping continues to the end of the file. If a closing code-
skipping or format-skipping comment appears in a file but does not follow a corresponding
opening comment, then it is treated as an ordinary comment without any special meaning.
It is recommended to use --code-skipping only if you need to hide a block of an extended
syntax which would produce errors if parsed by perltidy, and use --format-skipping
otherwise. This is because the --format-skipping option provides the benefits of error
checking, and there are essentially no limitations on which lines to which it can be
applied. The --code-skipping option, on the other hand, does not do error checking and
its use is more restrictive because the code which remains, after skipping the marked
lines, must be syntactically correct code with balanced containers.
These features should be used sparingly to avoid littering code with markers, but they can
be helpful for working around occasional problems.
Note that it may be possible to avoid the use of --format-skipping for the specific case
of a comma-separated list of values, as in the above example, by simply inserting a blank
or comment somewhere between the opening and closing parens. See the section "Controlling
List Formatting".
The following sections describe the available controls for these options. They should not
normally be needed.
-fs, --format-skipping
As explained above, this flag, which is enabled by default, causes any code between
special beginning and ending comment markers to be passed to the output without
formatting. The code between the comments is still checked for errors however. The
default beginning marker is #<<< and the default ending marker is #>>>.
Format skipping begins when a format skipping beginning comment is seen and continues
until a format-skipping ending comment is found.
This feature can be disabled with -nfs. This should not normally be necessary.
-fsb=string, --format-skipping-begin=string
This and the next parameter allow the special beginning and ending comments to be
changed. However, it is recommended that they only be changed if there is a conflict
between the default values and some other use. If they are used, it is recommended
that they only be entered in a .perltidyrc file, rather than on a command line. This
is because properly escaping these parameters on a command line can be difficult.
If changed comment markers do not appear to be working, use the -log flag and examine
the .LOG file to see if and where they are being detected.
The -fsb=string parameter may be used to change the beginning marker for format
skipping. The default is equivalent to -fsb='#<<<'. The string that you enter must
begin with a # and should be in quotes as necessary to get past the command shell of
your system. It is actually the leading text of a pattern that is constructed by
appending a '\s', so you must also include backslashes for characters to be taken
literally rather than as patterns.
Some examples show how example strings become patterns:
-fsb='#\{\{\{' becomes /^#\{\{\{\s/ which matches #{{{ but not #{{{{
-fsb='#\*\*' becomes /^#\*\*\s/ which matches #** but not #***
-fsb='#\*{2,}' becomes /^#\*{2,}\s/ which matches #** and #*****
-fse=string, --format-skipping-end=string
The -fse=string is the corresponding parameter used to change the ending marker for
format skipping. The default is equivalent to -fse='#<<<'.
The beginning and ending strings may be the same, but it is preferable to make them
different for clarity.
-cs, --code-skipping
As explained above, this flag, which is enabled by default, causes any code between
special beginning and ending comment markers to be directly passed to the output
without any error checking or formatting. Essentially, perltidy treats it as if it
were a block of arbitrary text. The default beginning marker is #<<V and the default
ending marker is #>>V.
This feature can be disabled with -ncs. This should not normally be necessary.
-csb=string, --code-skipping-begin=string
This may be used to change the beginning comment for a --code-skipping section, and
its use is similar to the -fsb=string. The default is equivalent to -csb='#<<V'.
-cse=string, --code-skipping-end=string
This may be used to change the ending comment for a --code-skipping section, and its
use is similar to the -fse=string. The default is equivalent to -cse='#>>V'.
Line Break Control
The parameters in this and the next sections control breaks after non-blank lines of code.
Blank lines are controlled separately by parameters in the section "Blank Line Control".
-dnl, --delete-old-newlines
By default, perltidy first deletes all old line break locations, and then it looks for
good break points to match the desired line length. Use -ndnl or
--nodelete-old-newlines to force perltidy to retain all old line break points.
-anl, --add-newlines
By default, perltidy will add line breaks when necessary to create continuations of
long lines and to improve the script appearance. Use -nanl or --noadd-newlines to
prevent any new line breaks.
This flag does not prevent perltidy from eliminating existing line breaks; see
--freeze-newlines to completely prevent changes to line break points.
-fnl, --freeze-newlines
If you do not want any changes to the line breaks within lines of code in your script,
set -fnl, and they will remain fixed, and the rest of the commands in this section and
sections "Controlling List Formatting", "Retaining or Ignoring Existing Line Breaks".
You may want to use -noll with this.
Note: If you also want to keep your blank lines exactly as they are, you can use the
-fbl flag which is described in the section "Blank Line Control".
Controlling Breaks at Braces, Parens, and Square Brackets
-ce, --cuddled-else
Enable the "cuddled else" style, in which "else" and "elsif" are follow immediately
after the curly brace closing the previous block. The default is not to use cuddled
elses, and is indicated with the flag -nce or --nocuddled-else. Here is a comparison
of the alternatives:
# -ce
if ($task) {
yyy();
} else {
zzz();
}
# -nce (default)
if ($task) {
yyy();
}
else {
zzz();
}
In this example the keyword else is placed on the same line which begins with the
preceding closing block brace and is followed by its own opening block brace on the
same line. Other keywords and function names which are formatted with this "cuddled"
style are elsif, continue, catch, finally.
Other block types can be formatted by specifying their names on a separate parameter
-cbl, described in a later section.
Cuddling between a pair of code blocks requires that the closing brace of the first
block start a new line. If this block is entirely on one line in the input file, it
is necessary to decide if it should be broken to allow cuddling. This decision is
controlled by the flag -cbo=n discussed below. The default and recommended value of
-cbo=1 bases this decision on the first block in the chain. If it spans multiple
lines then cuddling is made and continues along the chain, regardless of the sizes of
subsequent blocks. Otherwise, short lines remain intact.
So for example, the -ce flag would not have any effect if the above snippet is
rewritten as
if ($task) { yyy() }
else { zzz() }
If the first block spans multiple lines, then cuddling can be done and will continue
for the subsequent blocks in the chain, as illustrated in the previous snippet.
If there are blank lines between cuddled blocks they will be eliminated. If there are
comments after the closing brace where cuddling would occur then cuddling will be
prevented. If this occurs, cuddling will restart later in the chain if possible.
-cb, --cuddled-blocks
This flag is equivalent to -ce.
-cbl, --cuddled-block-list
The built-in default cuddled block types are else, elsif, continue, catch, finally.
Additional block types to which the -cuddled-blocks style applies can be defined by
this parameter. This parameter is a character string, giving a list of block types
separated by commas or spaces. For example, to cuddle code blocks of type sort, map
and grep, in addition to the default types, the string could be set to
-cbl="sort map grep"
or equivalently
-cbl=sort,map,grep
Note however that these particular block types are typically short so there might not
be much opportunity for the cuddled format style.
Using commas avoids the need to protect spaces with quotes.
As a diagnostic check, the flag --dump-cuddled-block-list or -dcbl can be used to view
the hash of values that are generated by this flag.
Finally, note that the -cbl flag by itself merely specifies which blocks are formatted
with the cuddled format. It has no effect unless this formatting style is activated
with -ce.
-cblx, --cuddled-block-list-exclusive
When cuddled else formatting is selected with -ce, setting this flag causes perltidy
to ignore its built-in defaults and rely exclusively on the block types specified on
the -cbl flag described in the previous section. For example, to avoid using cuddled
catch and finally, which are among the defaults, the following set of parameters could
be used:
perltidy -ce -cbl='else elsif continue' -cblx
-cbo=n, --cuddled-break-option=n
Cuddled formatting is only possible between a pair of code blocks if the closing brace
of the first block starts a new line. If a block is encountered which is entirely on a
single line, and cuddled formatting is selected, it is necessary to make a decision as
to whether or not to "break" the block, meaning to cause it to span multiple lines.
This parameter controls that decision. The options are:
cbo=0 Never force a short block to break.
cbo=1 If the first of a pair of blocks is broken in the input file,
then break the second [DEFAULT].
cbo=2 Break open all blocks for maximal cuddled formatting.
The default and recommended value is cbo=1. With this value, if the starting block of
a chain spans multiple lines, then a cascade of breaks will occur for remaining blocks
causing the entire chain to be cuddled.
The option cbo=0 can produce erratic cuddling if there are numerous one-line blocks.
The option cbo=2 produces maximal cuddling but will not allow any short blocks.
-bl, --opening-brace-on-new-line, or --brace-left
Use the flag -bl to place an opening block brace on a new line:
if ( $input_file eq '-' )
{
...
}
By default it applies to all structural blocks except sort map grep eval and anonymous
subs.
The default is -nbl which places an opening brace on the same line as the keyword
introducing it if possible. For example,
# default
if ( $input_file eq '-' ) {
...
}
When -bl is set, the blocks to which this applies can be controlled with the
parameters --brace-left-list and -brace-left-exclusion-list described in the next
sections.
-bll=s, --brace-left-list=s
Use this parameter to change the types of block braces for which the -bl flag applies;
see "Specifying Block Types". For example, -bll='if elsif else sub' would apply it to
only "if/elsif/else" and named sub blocks. The default is all blocks, -bll='*'.
-blxl=s, --brace-left-exclusion-list=s
Use this parameter to exclude types of block braces for which the -bl flag applies;
see "Specifying Block Types". For example, the default settings -bll='*' and
-blxl='sort map grep eval asub' mean all blocks except sort map grep eval and
anonymous sub blocks.
Note that the lists -bll=s and -blxl=s control the behavior of the -bl flag but have
no effect unless the -bl flag is set.
-sbl, --opening-sub-brace-on-new-line
The flag -sbl provides a shortcut way to turn on -bl just for named subs. The same
effect can be achieved by turning on -bl with the block list set as -bll='sub'.
For example,
perltidy -sbl
produces this result:
sub message
{
if (!defined($_[0])) {
print("Hello, World\n");
}
else {
print($_[0], "\n");
}
}
This flag is negated with -nsbl, which is the default.
-asbl, --opening-anonymous-sub-brace-on-new-line
The flag -asbl is like the -sbl flag except that it applies to anonymous sub's instead
of named subs. For example
perltidy -asbl
produces this result:
$a = sub
{
if ( !defined( $_[0] ) ) {
print("Hello, World\n");
}
else {
print( $_[0], "\n" );
}
};
This flag is negated with -nasbl, and the default is -nasbl.
-bli, --brace-left-and-indent
The flag -bli is similar to the -bl flag but in addition it causes one unit of
continuation indentation ( see -ci ) to be placed before an opening and closing block
braces.
For example, perltidy -bli gives
if ( $input_file eq '-' )
{
important_function();
}
By default, this extra indentation occurs for block types: if, elsif, else, unless,
while, for, foreach, do, and also named subs and blocks preceded by a label. The next
item shows how to change this.
Note: The -bli flag is similar to the -bl flag, with the difference being that braces
get indented. But these two flags are implemented independently, and have different
default settings for historical reasons. If desired, a mixture of effects can be
achieved if desired by turning them both on with different -list settings. In the
event that both settings are selected for a certain block type, the -bli style has
priority.
-blil=s, --brace-left-and-indent-list=s
Use this parameter to change the types of block braces for which the -bli flag
applies; see "Specifying Block Types".
The default is -blil='if else elsif unless while for foreach do : sub'.
-blixl=s, --brace-left-and-indent-exclusion-list=s
Use this parameter to exclude types of block braces for which the -bli flag applies;
see "Specifying Block Types".
This might be useful in conjunction with selecting all blocks -blil='*'. The default
setting is -blixl=' ', which does not exclude any blocks.
Note that the two parameters -blil and -blixl control the behavior of the -bli flag
but have no effect unless the -bli flag is set.
-bar, --opening-brace-always-on-right
The default style, -nbl places the opening code block brace on a new line if it does
not fit on the same line as the opening keyword, like this:
if ( $bigwasteofspace1 && $bigwasteofspace2
|| $bigwasteofspace3 && $bigwasteofspace4 )
{
big_waste_of_time();
}
To force the opening brace to always be on the right, use the -bar flag. In this
case, the above example becomes
if ( $bigwasteofspace1 && $bigwasteofspace2
|| $bigwasteofspace3 && $bigwasteofspace4 ) {
big_waste_of_time();
}
A conflict occurs if both -bl and -bar are specified.
-otr, --opening-token-right and related flags
The -otr flag is a hint that perltidy should not place a break between a comma and an
opening token. For example:
# default formatting
push @{ $self->{$module}{$key} },
{
accno => $ref->{accno},
description => $ref->{description}
};
# perltidy -otr
push @{ $self->{$module}{$key} }, {
accno => $ref->{accno},
description => $ref->{description}
};
The flag -otr is actually an abbreviation for three other flags which can be used to
control parens, hash braces, and square brackets separately if desired:
-opr or --opening-paren-right
-ohbr or --opening-hash-brace-right
-osbr or --opening-square-bracket-right
-bbhb=n, --break-before-hash-brace=n and related flags
When a list of items spans multiple lines, the default formatting is to place the
opening brace (or other container token) at the end of the starting line, like this:
$romanNumerals = {
one => 'I',
two => 'II',
three => 'III',
four => 'IV',
};
This flag can change the default behavior to cause a line break to be placed before
the opening brace according to the value given to the integer n:
-bbhb=0 never break [default]
-bbhb=1 stable: break if the input script had a break
-bbhb=2 break if list is 'complex' (see note below)
-bbhb=3 always break
For example,
# perltidy -bbhb=3
$romanNumerals =
{
one => 'I',
two => 'II',
three => 'III',
four => 'IV',
};
There are several points to note about this flag:
• This parameter only applies if the opening brace is preceded by an '=' or '=>'.
• This parameter only applies if the contents of the container looks like a list.
The contents need to contain some commas or '=>'s at the next interior level to be
considered a list.
• For the n=2 option, a list is considered 'complex' if it is part of a nested list
structure which spans multiple lines in the input file.
• If multiple opening tokens have been 'welded' together with the -wn parameter,
then this parameter has no effect.
• The indentation of the braces will normally be one level of continuation
indentation by default. This can be changed with the parameter -bbhbi=n in the
next section.
• Similar flags for controlling parens and square brackets are given in the
subsequent section.
-bbhbi=n, --break-before-hash-brace-and-indent=n
This flag is a companion to -bbhb=n for controlling the indentation of an opening hash
brace which is placed on a new line by that parameter. The indentation is as follows:
-bbhbi=0 one continuation level [default]
-bbhbi=1 outdent by one continuation level
-bbhbi=2 indent one full indentation level
For example:
# perltidy -bbhb=3 -bbhbi=1
$romanNumerals =
{
one => 'I',
two => 'II',
three => 'III',
four => 'IV',
};
# perltidy -bbhb=3 -bbhbi=2
$romanNumerals =
{
one => 'I',
two => 'II',
three => 'III',
four => 'IV',
};
Note that this parameter has no effect unless -bbhb=n is also set.
-bbsb=n, --break-before-square-bracket=n
This flag is similar to the flag described above, except it applies to lists contained
within square brackets.
-bbsb=0 never break [default]
-bbsb=1 stable: break if the input script had a break
-bbsb=2 break if list is 'complex' (part of nested list structure)
-bbsb=3 always break
-bbsbi=n, --break-before-square-bracket-and-indent=n
This flag is a companion to -bbsb=n for controlling the indentation of an opening
square bracket which is placed on a new line by that parameter. The indentation is as
follows:
-bbsbi=0 one continuation level [default]
-bbsbi=1 outdent by one continuation level
-bbsbi=2 indent one full indentation level
-bbp=n, --break-before-paren=n
This flag is similar to -bbhb=n, described above, except it applies to lists contained
within parens.
-bbp=0 never break [default]
-bbp=1 stable: break if the input script had a break
-bpb=2 break if list is 'complex' (part of nested list structure)
-bbp=3 always break
-bbpi=n, --break-before-paren-and-indent=n
This flag is a companion to -bbp=n for controlling the indentation of an opening paren
which is placed on a new line by that parameter. The indentation is as follows:
-bbpi=0 one continuation level [default]
-bbpi=1 outdent by one continuation level
-bbpi=2 indent one full indentation level
Welding
-wn, --weld-nested-containers
The -wn flag causes closely nested pairs of opening and closing container symbols
(curly braces, brackets, or parens) to be "welded" together, meaning that they are
treated as if combined into a single unit, with the indentation of the innermost code
reduced to be as if there were just a single container symbol.
For example:
# default formatting
do {
{
next if $x == $y;
}
} until $x++ > $z;
# perltidy -wn
do { {
next if $x == $y;
} } until $x++ > $z;
When this flag is set perltidy makes a preliminary pass through the file and
identifies all nested pairs of containers. To qualify as a nested pair, the closing
container symbols must be immediately adjacent and the opening symbols must either (1)
be adjacent as in the above example, or (2) have an anonymous sub declaration
following an outer opening container symbol which is not a code block brace, or (3)
have an outer opening paren separated from the inner opening symbol by any single non-
container symbol or something that looks like a function evaluation, as illustrated in
the next examples. An additional option (4) which can be turned on with the flag
--weld-fat-comma is when the opening container symbols are separated by a hash key and
fat comma (=>).
Any container symbol may serve as both the inner container of one pair and as the
outer container of an adjacent pair. Consequently, any number of adjacent opening or
closing symbols may join together in weld. For example, here are three levels of
wrapped function calls:
# default formatting
my (@date_time) = Localtime(
Date_to_Time(
Add_Delta_DHMS(
$year, $month, $day, $hour, $minute, $second,
'0', $offset, '0', '0'
)
)
);
# perltidy -wn
my (@date_time) = Localtime( Date_to_Time( Add_Delta_DHMS(
$year, $month, $day, $hour, $minute, $second,
'0', $offset, '0', '0'
) ) );
Notice how the indentation of the inner lines are reduced by two levels in this case.
This example also shows the typical result of this formatting, namely it is a sandwich
consisting of an initial opening layer, a central section of any complexity forming
the "meat" of the sandwich, and a final closing layer. This predictable structure
helps keep the compacted structure readable.
The inner sandwich layer is required to be at least one line thick. If this cannot be
achieved, welding does not occur. This constraint can cause formatting to take a
couple of iterations to stabilize when it is first applied to a script. The -conv flag
can be used to insure that the final format is achieved in a single run.
Here is an example illustrating a welded container within a welded containers:
# default formatting
$x->badd(
bmul(
$class->new(
abs(
$sx * int( $xr->numify() ) & $sy * int( $yr->numify() )
)
),
$m
)
);
# perltidy -wn
$x->badd( bmul(
$class->new( abs(
$sx * int( $xr->numify() ) & $sy * int( $yr->numify() )
) ),
$m
) );
The welded closing tokens are by default on a separate line but this can be modified
with the -vtc=n flag (described in the next section). For example, the same example
adding -vtc=2 is
# perltidy -wn -vtc=2
$x->badd( bmul(
$class->new( abs(
$sx * int( $xr->numify() ) & $sy * int( $yr->numify() ) ) ),
$m ) );
This format option is quite general but there are some limitations.
One limitation is that any line length limit still applies and can cause long welded
sections to be broken into multiple lines.
Another limitation is that an opening symbol which delimits quoted text cannot be
included in a welded pair. This is because quote delimiters are treated specially in
perltidy.
Finally, the stacking of containers defined by this flag have priority over any other
container stacking flags. This is because any welding is done first.
-wfc, --weld-fat-comma
When the -wfc flag is set, along with -wn, perltidy is allowed to weld an opening
paren to an inner opening container when they are separated by a hash key and fat
comma (=>). for example
# perltidy -wn -wfc
elf->call_method( method_name_foo => {
some_arg1 => $foo,
some_other_arg3 => $bar->{'baz'},
} );
This option is off by default.
-wnxl=s, --weld-nested-exclusion-list
The -wnxl=s flag provides some control over the types of containers which can be
welded. The -wn flag by default is "greedy" in welding adjacent containers. If it
welds more types of containers than desired, this flag provides a capability to reduce
the amount of welding by specifying a list of things which should not be welded.
The logic in perltidy to apply this is straightforward. As each container token is
being considered for joining a weld, any exclusion rules are consulted and used to
reject the weld if necessary.
This list is a string with space-separated items. Each item consists of up to three
pieces of information: (1) an optional position, (2) an optional preceding type, and
(3) a container type.
The only required piece of information is a container type, which is one of '(', '[',
'{' or 'q'. The first three of these are container tokens and the last represents a
quoted list. For example the string
-wnxl='[ { q'
means do NOT include square-brackets, braces, or quotes in any welds. The only
unspecified container is '(', so this string means that only welds involving parens
will be made.
To illustrate, following welded snippet consists of a chain of three welded containers
with types '(' '[' and 'q':
# perltidy -wn
skip_symbols( [ qw(
Perl_dump_fds
Perl_ErrorNo
Perl_GetVars
PL_sys_intern
) ] );
Even though the qw term uses parens as the quote delimiter, it has a special type 'q'
here. If it appears in a weld it always appears at the end of the welded chain.
Any of the container types '[', '{', and '(' may be prefixed with a position indicator
which is either '^', to indicate the first token of a welded sequence, or '.', to
indicate an interior token of a welded sequence. (Since a quoted string 'q' always
ends a chain it does need a position indicator).
For example, if we do not want a sequence of welded containers to start with a square
bracket we could use
-wnxl='^['
In the above snippet, there is a square bracket but it does not start the chain, so
the formatting would be unchanged if it were formatted with this restriction.
A third optional item of information which can be given is an alphanumeric letter
which is used to limit the selection further depending on the type of token
immediately before the container. If given, it goes just before the container symbol.
The possible letters are currently 'k', 'K', 'f', 'F', 'w', and 'W', with these
meanings:
'k' matches if the previous nonblank token is a perl built-in keyword (such as 'if', 'while'),
'K' matches if 'k' does not, meaning that the previous token is not a keyword.
'f' matches if the previous token is a function other than a keyword.
'F' matches if 'f' does not.
'w' matches if either 'k' or 'f' match.
'W' matches if 'w' does not.
For example, compare
# perltidy -wn
if ( defined( $_Cgi_Query{
$Config{'methods'}{'authentication'}{'remote'}{'cgi'}{'username'}
} ) )
with
# perltidy -wn -wnxl='^K( {'
if ( defined(
$_Cgi_Query{ $Config{'methods'}{'authentication'}{'remote'}{'cgi'}
{'username'} }
) )
The first case does maximum welding. In the second case the leading paren is retained
by the rule (it would have been rejected if preceded by a non-keyword) but the curly
brace is rejected by the rule.
Here are some additional example strings and their meanings:
'^(' - the weld must not start with a paren
'.(' - the second and later tokens may not be parens
'.w(' - the second and later tokens may not keyword or function call parens
'(' - no parens in a weld
'^K(' - exclude a leading paren preceded by a non-keyword
'.k(' - exclude a secondary paren preceded by a keyword
'[ {' - exclude all brackets and braces
'[ ( ^K{' - exclude everything except nested structures like do {{ ... }}
Vertical tightness of non-block curly braces, parentheses, and square brackets.
These parameters control what shall be called vertical tightness. Here are the main
points:
• Opening tokens (except for block braces) are controlled by -vt=n, or
--vertical-tightness=n, where
-vt=0 always break a line after opening token (default).
-vt=1 do not break unless this would produce more than one
step in indentation in a line.
-vt=2 never break a line after opening token
• You must also use the -lp flag when you use the -vt flag; the reason is explained
below.
• Closing tokens (except for block braces) are controlled by -vtc=n, or
--vertical-tightness-closing=n, where
-vtc=0 always break a line before a closing token (default),
-vtc=1 do not break before a closing token which is followed
by a semicolon or another closing token, and is not in
a list environment.
-vtc=2 never break before a closing token.
-vtc=3 Like -vtc=1 except always break before a closing token
if the corresponding opening token follows an = or =>.
The rules for -vtc=1 and -vtc=3 are designed to maintain a reasonable balance
between tightness and readability in complex lists.
• Different controls may be applied to different token types, and it is also
possible to control block braces; see below.
• Finally, please note that these vertical tightness flags are merely hints to the
formatter, and it cannot always follow them. Things which make it difficult or
impossible include comments, blank lines, blocks of code within a list, and
possibly the lack of the -lp parameter. Also, these flags may be ignored for very
small lists (2 or 3 lines in length).
Here are some examples:
# perltidy -lp -vt=0 -vtc=0
%romanNumerals = (
one => 'I',
two => 'II',
three => 'III',
four => 'IV',
);
# perltidy -lp -vt=1 -vtc=0
%romanNumerals = ( one => 'I',
two => 'II',
three => 'III',
four => 'IV',
);
# perltidy -lp -vt=1 -vtc=1
%romanNumerals = ( one => 'I',
two => 'II',
three => 'III',
four => 'IV', );
# perltidy -vtc=3
my_function(
one => 'I',
two => 'II',
three => 'III',
four => 'IV', );
# perltidy -vtc=3
%romanNumerals = (
one => 'I',
two => 'II',
three => 'III',
four => 'IV',
);
In the last example for -vtc=3, the opening paren is preceded by an equals so the
closing paren is placed on a new line.
The difference between -vt=1 and -vt=2 is shown here:
# perltidy -lp -vt=1
$init->add(
mysprintf( "(void)find_threadsv(%s);",
cstring( $threadsv_names[ $op->targ ] )
)
);
# perltidy -lp -vt=2
$init->add( mysprintf( "(void)find_threadsv(%s);",
cstring( $threadsv_names[ $op->targ ] )
)
);
With -vt=1, the line ending in "add(" does not combine with the next line because the
next line is not balanced. This can help with readability, but -vt=2 can be used to
ignore this rule.
The tightest, and least readable, code is produced with both "-vt=2" and "-vtc=2":
# perltidy -lp -vt=2 -vtc=2
$init->add( mysprintf( "(void)find_threadsv(%s);",
cstring( $threadsv_names[ $op->targ ] ) ) );
Notice how the code in all of these examples collapses vertically as -vt increases,
but the indentation remains unchanged. This is because perltidy implements the -vt
parameter by first formatting as if -vt=0, and then simply overwriting one output line
on top of the next, if possible, to achieve the desired vertical tightness. The -lp
indentation style has been designed to allow this vertical collapse to occur, which is
why it is required for the -vt parameter.
The -vt=n and -vtc=n parameters apply to each type of container token. If desired,
vertical tightness controls can be applied independently to each of the closing
container token types.
The parameters for controlling parentheses are -pvt=n or --paren-vertical-tightness=n,
and -pvtc=n or --paren-vertical-tightness-closing=n.
Likewise, the parameters for square brackets are -sbvt=n or
--square-bracket-vertical-tightness=n, and -sbvtc=n or
--square-bracket-vertical-tightness-closing=n.
Finally, the parameters for controlling non-code block braces are -bvt=n or
--brace-vertical-tightness=n, and -bvtc=n or --brace-vertical-tightness-closing=n.
In fact, the parameter -vt=n is actually just an abbreviation for -pvt=n -bvt=n
sbvt=n, and likewise -vtc=n is an abbreviation for -pvtc=n -bvtc=n -sbvtc=n.
-bbvt=n or --block-brace-vertical-tightness=n
The -bbvt=n flag is just like the -vt=n flag but applies to opening code block braces.
-bbvt=0 break after opening block brace (default).
-bbvt=1 do not break unless this would produce more than one
step in indentation in a line.
-bbvt=2 do not break after opening block brace.
It is necessary to also use either -bl or -bli for this to work, because, as with
other vertical tightness controls, it is implemented by simply overwriting a line
ending with an opening block brace with the subsequent line. For example:
# perltidy -bli -bbvt=0
if ( open( FILE, "< $File" ) )
{
while ( $File = <FILE> )
{
$In .= $File;
$count++;
}
close(FILE);
}
# perltidy -bli -bbvt=1
if ( open( FILE, "< $File" ) )
{ while ( $File = <FILE> )
{ $In .= $File;
$count++;
}
close(FILE);
}
By default this applies to blocks associated with keywords if, elsif, else, unless,
for, foreach, sub, while, until, and also with a preceding label. This can be changed
with the parameter -bbvtl=string, or --block-brace-vertical-tightness-list=string,
where string is a space-separated list of block types. For more information on the
possible values of this string, see "Specifying Block Types"
For example, if we want to just apply this style to "if", "elsif", and "else" blocks,
we could use "perltidy -bli -bbvt=1 -bbvtl='if elsif else'".
There is no vertical tightness control for closing block braces; with one exception
they will be placed on separate lines. The exception is that a cascade of closing
block braces may be stacked on a single line. See -scbb.
-sot, --stack-opening-tokens and related flags
The -sot flag tells perltidy to "stack" opening tokens when possible to avoid lines
with isolated opening tokens.
For example:
# default
$opt_c = Text::CSV_XS->new(
{
binary => 1,
sep_char => $opt_c,
always_quote => 1,
}
);
# -sot
$opt_c = Text::CSV_XS->new( {
binary => 1,
sep_char => $opt_c,
always_quote => 1,
}
);
For detailed control of individual closing tokens the following controls can be used:
-sop or --stack-opening-paren
-sohb or --stack-opening-hash-brace
-sosb or --stack-opening-square-bracket
-sobb or --stack-opening-block-brace
The flag -sot is an abbreviation for -sop -sohb -sosb.
The flag -sobb is an abbreviation for -bbvt=2 -bbvtl='*'. This will case a cascade of
opening block braces to appear on a single line, although this an uncommon occurrence
except in test scripts.
-sct, --stack-closing-tokens and related flags
The -sct flag tells perltidy to "stack" closing tokens when possible to avoid lines
with isolated closing tokens.
For example:
# default
$opt_c = Text::CSV_XS->new(
{
binary => 1,
sep_char => $opt_c,
always_quote => 1,
}
);
# -sct
$opt_c = Text::CSV_XS->new(
{
binary => 1,
sep_char => $opt_c,
always_quote => 1,
} );
The -sct flag is somewhat similar to the -vtc flags, and in some cases it can give a
similar result. The difference is that the -vtc flags try to avoid lines with leading
opening tokens by "hiding" them at the end of a previous line, whereas the -sct flag
merely tries to reduce the number of lines with isolated closing tokens by stacking
them but does not try to hide them. For example:
# -vtc=2
$opt_c = Text::CSV_XS->new(
{
binary => 1,
sep_char => $opt_c,
always_quote => 1, } );
For detailed control of the stacking of individual closing tokens the following
controls can be used:
-scp or --stack-closing-paren
-schb or --stack-closing-hash-brace
-scsb or --stack-closing-square-bracket
-scbb or --stack-closing-block-brace
The flag -sct is an abbreviation for stacking the non-block closing tokens, -scp -schb
-scsb.
Stacking of closing block braces, -scbb, causes a cascade of isolated closing block
braces to be combined into a single line as in the following example:
# -scbb:
for $w1 (@w1) {
for $w2 (@w2) {
for $w3 (@w3) {
for $w4 (@w4) {
push( @lines, "$w1 $w2 $w3 $w4\n" );
} } } }
To simplify input even further for the case in which both opening and closing non-
block containers are stacked, the flag -sac or --stack-all-containers is an
abbreviation for -sot -sct.
Please note that if both opening and closing tokens are to be stacked, then the newer
flag -weld-nested-containers may be preferable because it insures that stacking is
always done symmetrically. It also removes an extra level of unnecessary indentation
within welded containers. It is able to do this because it works on formatting
globally rather than locally, as the -sot and -sct flags do.
Breaking Before or After Operators
Four command line parameters provide some control over whether a line break should be
before or after specific token types. Two parameters give detailed control:
-wba=s or --want-break-after=s, and
-wbb=s or --want-break-before=s.
These parameters are each followed by a quoted string, s, containing a list of token types
(separated only by spaces). No more than one of each of these parameters should be
specified, because repeating a command-line parameter always overwrites the previous one
before perltidy ever sees it.
By default, perltidy breaks after these token types:
% + - * / x != == >= <= =~ !~ < > | &
= **= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x=
And perltidy breaks before these token types by default:
. << >> -> && || //
To illustrate, to cause a break after a concatenation operator, '.', rather than before
it, the command line would be
-wba="."
As another example, the following command would cause a break before math operators '+',
'-', '/', and '*':
-wbb="+ - / *"
These commands should work well for most of the token types that perltidy uses (use
--dump-token-types for a list). Also try the -D flag on a short snippet of code and look
at the .DEBUG file to see the tokenization. However, for a few token types there may be
conflicts with hardwired logic which cause unexpected results. One example is curly
braces, which should be controlled with the parameter bl provided for that purpose.
WARNING Be sure to put these tokens in quotes to avoid having them misinterpreted by your
command shell.
Two additional parameters are available which, though they provide no further capability,
can simplify input are:
-baao or --break-after-all-operators,
-bbao or --break-before-all-operators.
The -baao sets the default to be to break after all of the following operators:
% + - * / x != == >= <= =~ !~ < > | &
= **= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x=
. : ? && || and or err xor
and the -bbao flag sets the default to break before all of these operators. These can be
used to define an initial break preference which can be fine-tuned with the -wba and -wbb
flags. For example, to break before all operators except an = one could use --bbao
-wba='=' rather than listing every single perl operator except = on a -wbb flag.
-bal=n, --break-after-labels=n
This flag controls whether or not a line break occurs after a label. There are three
possible values for n:
-bal=0 break if there is a break in the input [DEFAULT]
-bal=1 always break after a label
-bal=2 never break after a label
For example,
# perltidy -bal=1
RETURN:
return;
# perltidy -bal=2
RETURN: return;
Controlling List Formatting
Perltidy attempts to format lists of comma-separated values in tables which look good.
Its default algorithms usually work well, but sometimes they don't. In this case, there
are several methods available to control list formatting.
A very simple way to prevent perltidy from changing the line breaks within a comma-
separated list of values is to insert a blank line, comment, or side-comment anywhere
between the opening and closing parens (or braces or brackets). This causes perltidy to
skip over its list formatting logic. (The reason is that any of these items put a
constraint on line breaks, and perltidy needs complete control over line breaks within a
container to adjust a list layout). For example, let us consider
my @list = (1,
1, 1,
1, 2, 1,
1, 3, 3, 1,
1, 4, 6, 4, 1,);
The default formatting, which allows a maximum line length of 80, will flatten this down
to one line:
# perltidy (default)
my @list = ( 1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, );
This formatting loses the nice structure. If we place a side comment anywhere between the
opening and closing parens, the original line break points are retained. For example,
my @list = (
1, # a side comment forces the original line breakpoints to be kept
1, 1,
1, 2, 1,
1, 3, 3, 1,
1, 4, 6, 4, 1,
);
The side comment can be a single hash symbol without any text. We could achieve the same
result with a blank line or full comment anywhere between the opening and closing parens.
Vertical alignment of the list items will still occur if possible.
For another possibility see the -fs flag in "Skipping Selected Sections of Code".
-boc, --break-at-old-comma-breakpoints
The -boc flag is another way to prevent comma-separated lists from being reformatted.
Using -boc on the above example, plus additional flags to retain the original style,
yields
# perltidy -boc -lp -pt=2 -vt=1 -vtc=1
my @list = (1,
1, 1,
1, 2, 1,
1, 3, 3, 1,
1, 4, 6, 4, 1,);
A disadvantage of this flag compared to the methods discussed above is that all tables
in the file must already be nicely formatted.
-mft=n, --maximum-fields-per-table=n
If n is a positive number, and the computed number of fields for any table exceeds n,
then it will be reduced to n. This parameter might be used on a small section of code
to force a list to have a particular number of fields per line, and then either the
-boc flag could be used to retain this formatting, or a single comment could be
introduced somewhere to freeze the formatting in future applications of perltidy. For
example
# perltidy -mft=2
@month_of_year = (
'Jan', 'Feb',
'Mar', 'Apr',
'May', 'Jun',
'Jul', 'Aug',
'Sep', 'Oct',
'Nov', 'Dec'
);
The default value is n=0, which does not place a limit on the number of fields in a
table.
-cab=n, --comma-arrow-breakpoints=n
A comma which follows a comma arrow, '=>', is given special consideration. In a long
list, it is common to break at all such commas. This parameter can be used to control
how perltidy breaks at these commas. (However, it will have no effect if old comma
breaks are being forced because -boc is used). The possible values of n are:
n=0 break at all commas after =>
n=1 stable: break at all commas after => if container is open,
EXCEPT FOR one-line containers
n=2 break at all commas after =>, BUT try to form the maximum
one-line container lengths
n=3 do not treat commas after => specially at all
n=4 break everything: like n=0 but ALSO break a short container with
a => not followed by a comma when -vt=0 is used
n=5 stable: like n=1 but ALSO break at open one-line containers when
-vt=0 is used (default)
For example, given the following single line, perltidy by default will not add any
line breaks because it would break the existing one-line container:
bless { B => $B, Root => $Root } => $package;
Using -cab=0 will force a break after each comma-arrow item:
# perltidy -cab=0:
bless {
B => $B,
Root => $Root
} => $package;
If perltidy is subsequently run with this container broken, then by default it will
break after each '=>' because the container is now broken. To reform a one-line
container, the parameter -cab=2 could be used.
The flag -cab=3 can be used to prevent these commas from being treated specially. In
this case, an item such as "01" => 31 is treated as a single item in a table. The
number of fields in this table will be determined by the same rules that are used for
any other table. Here is an example.
# perltidy -cab=3
my %last_day = (
"01" => 31, "02" => 29, "03" => 31, "04" => 30,
"05" => 31, "06" => 30, "07" => 31, "08" => 31,
"09" => 30, "10" => 31, "11" => 30, "12" => 31
);
Adding and Deleting Commas
-drc, --delete-repeated-commas
Repeated commas in a list are undesirable and can be removed with this flag. For
example, given this list with a repeated comma
ignoreSpec( $file, "file",, \%spec, \%Rspec );
we can remove it with -drc
# perltidy -drc:
ignoreSpec( $file, "file", \%spec, \%Rspec );
Since the default is not to add or delete commas, this feature is off by default and
must be requested.
--want-trailing-commas=s or -wtc=s, --add-trailing-commas or -atc, and
--delete-trailing-commas or -dtc
A trailing comma is a comma following the last item of a list. Perl allows trailing
commas but they are not required. By default, perltidy does not add or delete
trailing commas, but it is possible to manipulate them with the following set of three
related parameters:
--want-trailing-commas=s, -wtc=s - defines where trailing commas are wanted
--add-trailing-commas, -atc - gives permission to add trailing commas to match the style wanted
--delete-trailing-commas, -dtc - gives permission to delete trailing commas which do not match the style wanted
The parameter --want-trailing-commas=s, or -wtc=s, defines a preferred style. The
string s indicates which lists should get trailing commas, as follows:
s=0 : no list should have a trailing comma
s=1 or * : every list should have a trailing comma
s=m a multi-line list should have a trailing commas
s=b trailing commas should be 'bare' (comma followed by newline)
s=h lists of key=>value pairs, with about one one '=>' and one ',' per line,
with a bare trailing comma
s=i lists with about one comma per line, with a bare trailing comma
s=' ' or -wtc not defined : leave trailing commas unchanged [DEFAULT].
This parameter by itself only indicates the where trailing commas are wanted.
Perltidy only adds these trailing commas if the flag --add-trailing-commas, or -atc is
set. And perltidy only removes unwanted trailing commas if the flag
--delete-trailing-commas, or -dtc is set.
Here are some example parameter combinations and their meanings
-wtc=0 -dtc : delete all trailing commas
-wtc=1 -atc : all lists get trailing commas
-wtc=m -atc : all multi-line lists get trailing commas, but
single line lists remain unchanged.
-wtc=m -dtc : multi-line lists remain unchanged, but
any trailing commas on single line lists are removed.
-wtc=m -atc -dtc : all multi-line lists get trailing commas, and
any trailing commas on single line lists are removed.
For example, given the following input without a trailing comma
bless {
B => $B,
Root => $Root
} => $package;
we can add a trailing comma after the variable $Root using
# perltidy -wtc=m -atc
bless {
B => $B,
Root => $Root,
} => $package;
This could also be achieved in this case with -wtc=b instead of -wtc=m because the
trailing comma here is bare (separated from its closing brace by a newline). And it
could also be achieved with -wtc=h because this particular list is a list of
key=>value pairs.
The above styles should cover the main of situations of interest, but it is possible
to apply a different style to each type of container token by including an opening
token ahead of the style character in the above table. For example
-wtc='(m [b'
means that lists within parens should have multi-line trailing commas, and that lists
within square brackets have bare trailing commas. Since there is no specification for
curly braces in this example, their trailing commas would remain unchanged.
For parentheses, an additional item of information which can be given is an
alphanumeric letter which is used to limit the selection further depending on the type
of token immediately before the opening paren. The possible letters are currently
'k', 'K', 'f', 'F', 'w', and 'W', with these meanings for matching whatever precedes
an opening paren:
'k' matches if the previous nonblank token is a perl built-in keyword (such as 'if', 'while'),
'K' matches if 'k' does not, meaning that the previous token is not a keyword.
'f' matches if the previous token is a function other than a keyword.
'F' matches if 'f' does not.
'w' matches if either 'k' or 'f' match.
'W' matches if 'w' does not.
These are the same codes used for --line-up-parentheses-inclusion-list. For example,
-wtc = 'w(m'
means that trailing commas are wanted for multi-line parenthesized lists following a
function call or keyword.
Here are some points to note regarding adding and deleting trailing commas:
• For the implementation of these parameters, a list is basically taken to be a
container of items (parens, square brackets, or braces), which is not a code
block, with one or more commas. These parameters only apply to something that
fits this definition of a list.
Note that a paren-less list of parameters is not a list by this definition, so
these parameters have no effect on a peren-less list.
Another consequence is that if the only comma in a list is deleted, then it cannot
later be added back with these parameters because the container no longer fits
this definition of a list. For example, given
my ( $self, ) = @_;
and if we remove the comma with
# perltidy -wtc=m -dtc
my ( $self ) = @_;
then we cannot use these trailing comma controls to add this comma back.
• By multiline list is meant a list for which the first comma and trailing comma are
on different lines.
• A bare trailing comma is a comma which is at the end of a line. That is, the
closing container token follows on a different line. So a list with a bare
trailing comma is a special case of a multi-line list.
• The decision regarding whether or not a list is multi-line or bare is made based
on the input stream. In some cases it may take an iteration or two to reach a
final state.
• When using these parameters for the first time it is a good idea to practice on
some test scripts and verify that the results are as expected.
• Since the default behavior is not to add or delete commas, these parameters can be
useful on a temporary basis for reformatting a script.
-dwic, --delete-weld-interfering-commas
If the closing tokens of two nested containers are separated by a comma, then welding
requested with --weld-nested-containers cannot occur. Any commas in this situation
are optional trailing commas and can be removed with -dwic. For example, a comma in
this script prevents welding:
# perltidy -wn
skip_symbols(
[ qw(
Perl_dump_fds
Perl_ErrorNo
Perl_GetVars
PL_sys_intern
) ],
);
Using -dwic removes the comma and allows welding:
# perltidy -wn -dwic
skip_symbols( [ qw(
Perl_dump_fds
Perl_ErrorNo
Perl_GetVars
PL_sys_intern
) ] );
Since the default is not to add or delete commas, this feature is off by default.
Here are some points to note about the -dwic parameter
• This operation is not reversible, so please check results of using this parameter
carefully.
• Removing this type of isolated trailing comma is necessary for welding to be
possible, but not sufficient. So welding will not always occur where these commas
are removed.
Retaining or Ignoring Existing Line Breaks
Several additional parameters are available for controlling the extent to which line
breaks in the input script influence the output script. In most cases, the default
parameter values are set so that, if a choice is possible, the output style follows the
input style. For example, if a short logical container is broken in the input script,
then the default behavior is for it to remain broken in the output script.
Most of the parameters in this section would only be required for a one-time conversion of
a script from short container lengths to longer container lengths. The opposite effect,
of converting long container lengths to shorter lengths, can be obtained by temporarily
using a short maximum line length.
-bol, --break-at-old-logical-breakpoints
By default, if a logical expression is broken at a "&&", "||", "and", or "or", then
the container will remain broken. Also, breaks at internal keywords "if" and "unless"
will normally be retained. To prevent this, and thus form longer lines, use -nbol.
Please note that this flag does not duplicate old logical breakpoints. They are
merely used as a hint with this flag that a statement should remain broken. Without
this flag, perltidy will normally try to combine relatively short expressions into a
single line.
For example, given this snippet:
return unless $cmd = $cmd || ($dot
&& $Last_Shell) || &prompt('|');
# perltidy -bol [default]
return
unless $cmd = $cmd
|| ( $dot
&& $Last_Shell )
|| &prompt('|');
# perltidy -nbol
return unless $cmd = $cmd || ( $dot && $Last_Shell ) || &prompt('|');
-bom, --break-at-old-method-breakpoints
By default, a method call arrow "->" is considered a candidate for a breakpoint, but
method chains will fill to the line width before a break is considered. With -bom,
breaks before the arrow are preserved, so if you have pre-formatted a method chain:
my $q = $rs
->related_resultset('CDs')
->related_resultset('Tracks')
->search({
'track.id' => {-ident => 'none_search.id'},
})->as_query;
It will keep these breaks, rather than become this:
my $q = $rs->related_resultset('CDs')->related_resultset('Tracks')->search({
'track.id' => {-ident => 'none_search.id'},
})->as_query;
This flag will also look for and keep a 'cuddled' style of calls, in which lines begin
with a closing paren followed by a call arrow, as in this example:
# perltidy -bom -wn
my $q = $rs->related_resultset(
'CDs'
)->related_resultset(
'Tracks'
)->search( {
'track.id' => { -ident => 'none_search.id' },
} )->as_query;
You may want to include the -weld-nested-containers flag in this case to keep nested
braces and parens together, as in the last line.
-bos, --break-at-old-semicolon-breakpoints
Semicolons are normally placed at the end of a statement. This means that formatted
lines do not normally begin with semicolons. If the input stream has some lines which
begin with semicolons, these can be retained by setting this flag. For example,
consider the following two-line input snippet:
$z = sqrt($x**2 + $y**2)
;
The default formatting will be:
$z = sqrt( $x**2 + $y**2 );
The result using perltidy -bos keeps the isolated semicolon:
$z = sqrt( $x**2 + $y**2 )
;
The default is not to do this, -nbos.
-bok, --break-at-old-keyword-breakpoints
By default, perltidy will retain a breakpoint before keywords which may return lists,
such as "sort" and <map>. This allows chains of these operators to be displayed one
per line. Use -nbok to prevent retaining these breakpoints.
-bot, --break-at-old-ternary-breakpoints
By default, if a conditional (ternary) operator is broken at a ":", then it will
remain broken. To prevent this, and thereby form longer lines, use -nbot.
-boa, --break-at-old-attribute-breakpoints
By default, if an attribute list is broken at a ":" in the source file, then it will
remain broken. For example, given the following code, the line breaks at the ':'s
will be retained:
my @field
: field
: Default(1)
: Get('Name' => 'foo') : Set('Name');
If the attributes are on a single line in the source code then they will remain on a
single line if possible.
To prevent this, and thereby always form longer lines, use -nboa.
Keeping old breakpoints at specific token types
It is possible to override the choice of line breaks made by perltidy, and force it to
follow certain line breaks in the input stream, with these two parameters:
-kbb=s or --keep-old-breakpoints-before=s, and
-kba=s or --keep-old-breakpoints-after=s
These parameters are each followed by a quoted string, s, containing a list of token
types (separated only by spaces). No more than one of each of these parameters should
be specified, because repeating a command-line parameter always overwrites the
previous one before perltidy ever sees it.
For example, -kbb='=>' means that if an input line begins with a '=>' then the output
script should also have a line break before that token.
For example, given the script:
method 'foo'
=> [ Int, Int ]
=> sub {
my ( $self, $x, $y ) = ( shift, @_ );
...;
};
# perltidy [default]
method 'foo' => [ Int, Int ] => sub {
my ( $self, $x, $y ) = ( shift, @_ );
...;
};
# perltidy -kbb='=>'
method 'foo'
=> [ Int, Int ]
=> sub {
my ( $self, $x, $y ) = ( shift, @_ );
...;
};
For the container tokens '{', '[' and '(' and, their closing counterparts, use the
token symbol. Thus, the command to keep a break after all opening parens is:
perltidy -kba='('
It is possible to be more specific in matching parentheses by preceding them with a
letter. The possible letters are 'k', 'K', 'f', 'F', 'w', and 'W', with these
meanings (these are the same as used in the --weld-nested-exclusion-list and
--line-up-parentheses-exclusion-list parameters):
'k' matches if the previous nonblank token is a perl built-in keyword (such as 'if', 'while'),
'K' matches if 'k' does not, meaning that the previous token is not a keyword.
'f' matches if the previous token is a function other than a keyword.
'F' matches if 'f' does not.
'w' matches if either 'k' or 'f' match.
'W' matches if 'w' does not.
So for example the the following parameter will keep breaks after opening function
call parens:
perltidy -kba='f('
NOTE: A request to break before an opening container, such as -kbb='(', will be
silently ignored because it can lead to formatting instability. Likewise, a request
to break after a closing container, such as -kba=')', will also be silently ignored.
-iob, --ignore-old-breakpoints
Use this flag to tell perltidy to ignore existing line breaks to the maximum extent
possible. This will tend to produce the longest possible containers, regardless of
type, which do not exceed the line length limit. But please note that this parameter
has priority over all other parameters requesting that certain old breakpoints be
kept.
To illustrate, consider the following input text:
has subcmds => (
is => 'ro',
default => sub { [] },
);
The default formatting will keep the container broken, giving
# perltidy [default]
has subcmds => (
is => 'ro',
default => sub { [] },
);
If old breakpoints are ignored, the list will be flattened:
# perltidy -iob
has subcmds => ( is => 'ro', default => sub { [] }, );
Besides flattening lists, this parameter also applies to lines broken at certain
logical breakpoints such as 'if' and 'or'.
Even if this is parameter is not used globally, it provides a convenient way to
flatten selected lists from within an editor.
-kis, --keep-interior-semicolons
Use the -kis flag to prevent breaking at a semicolon if there was no break there in
the input file. Normally perltidy places a newline after each semicolon which
terminates a statement unless several statements are contained within a one-line brace
block. To illustrate, consider the following input lines:
dbmclose(%verb_delim); undef %verb_delim;
dbmclose(%expanded); undef %expanded;
The default is to break after each statement, giving
dbmclose(%verb_delim);
undef %verb_delim;
dbmclose(%expanded);
undef %expanded;
With perltidy -kis the multiple statements are retained:
dbmclose(%verb_delim); undef %verb_delim;
dbmclose(%expanded); undef %expanded;
The statements are still subject to the specified value of maximum-line-length and
will be broken if this maximum is exceeded.
Blank Line Control
Blank lines can improve the readability of a script if they are carefully placed.
Perltidy has several commands for controlling the insertion, retention, and removal of
blank lines.
-fbl, --freeze-blank-lines
Set -fbl if you want to the blank lines in your script to remain exactly as they are.
The rest of the parameters in this section may then be ignored. (Note: setting the
-fbl flag is equivalent to setting -mbl=0 and -kbl=2).
-bbc, --blanks-before-comments
A blank line will be introduced before a full-line comment. This is the default. Use
-nbbc or --noblanks-before-comments to prevent such blank lines from being
introduced.
-blbs=n, --blank-lines-before-subs=n
The parameter -blbs=n requests that least n blank lines precede a sub definition which
does not follow a comment and which is more than one-line long. The default is
<-blbs=1>. BEGIN and END blocks are included.
The requested number of blanks statement will be inserted regardless of the value of
--maximum-consecutive-blank-lines=n (-mbl=n) with the exception that if -mbl=0 then no
blanks will be output.
This parameter interacts with the value k of the parameter
--maximum-consecutive-blank-lines=k (-mbl=k) as follows:
1. If -mbl=0 then no blanks will be output. This allows all blanks to be suppressed
with a single parameter. Otherwise,
2. If the number of old blank lines in the script is less than n then additional
blanks will be inserted to make the total n regardless of the value of -mbl=k.
3. If the number of old blank lines in the script equals or exceeds n then this
parameter has no effect, however the total will not exceed value specified on the
-mbl=k flag.
-blbp=n, --blank-lines-before-packages=n
The parameter -blbp=n requests that least n blank lines precede a package which does
not follow a comment. The default is -blbp=1.
This parameter interacts with the value k of the parameter
--maximum-consecutive-blank-lines=k (-mbl=k) in the same way as described for the
previous item -blbs=n.
-bbs, --blanks-before-subs
For compatibility with previous versions, -bbs or --blanks-before-subs is equivalent
to -blbp=1 and -blbs=1.
Likewise, -nbbs or --noblanks-before-subs is equivalent to -blbp=0 and -blbs=0.
-bbb, --blanks-before-blocks
A blank line will be introduced before blocks of coding delimited by for, foreach,
while, until, and if, unless, in the following circumstances:
• The block is not preceded by a comment.
• The block is not a one-line block.
• The number of consecutive non-blank lines at the current indentation depth is at
least -lbl (see next section).
This is the default. The intention of this option is to introduce some space within
dense coding. This is negated with -nbbb or --noblanks-before-blocks.
-lbl=n --long-block-line-count=n
This controls how often perltidy is allowed to add blank lines before certain block
types (see previous section). The default is 8. Entering a value of 0 is equivalent
to entering a very large number.
-blao=i or --blank-lines-after-opening-block=i
This control places a minimum of i blank lines after a line which ends with an opening
block brace of a specified type. By default, this only applies to the block of a
named sub, but this can be changed (see -blaol below). The default is not to do this
(i=0).
Please see the note below on using the -blao and -blbc options.
-blbc=i or --blank-lines-before-closing-block=i
This control places a minimum of i blank lines before a line which begins with a
closing block brace of a specified type. By default, this only applies to the block
of a named sub, but this can be changed (see -blbcl below). The default is not to do
this (i=0).
-blaol=s or --blank-lines-after-opening-block-list=s
The parameter s is a list of block type keywords to which the flag -blao should apply.
The section "Specifying Block Types" explains how to list block types.
-blbcl=s or --blank-lines-before-closing-block-list=s
This parameter is a list of block type keywords to which the flag -blbc should apply.
The section "Specifying Block Types" explains how to list block types.
Note on using the -blao and -blbc options.
These blank line controls introduce a certain minimum number of blank lines in the
text, but the final number of blank lines may be greater, depending on values of the
other blank line controls and the number of old blank lines. A consequence is that
introducing blank lines with these and other controls cannot be exactly undone, so
some experimentation with these controls is recommended before using them.
For example, suppose that for some reason we decide to introduce one blank space at
the beginning and ending of all blocks. We could do this using
perltidy -blao=2 -blbc=2 -blaol='*' -blbcl='*' filename
Now suppose the script continues to be developed, but at some later date we decide we
don't want these spaces after all. We might expect that running with the flags -blao=0
and -blbc=0 will undo them. However, by default perltidy retains single blank lines,
so the blank lines remain.
We can easily fix this by telling perltidy to ignore old blank lines by including the
added parameter -kbl=0 and rerunning. Then the unwanted blank lines will be gone.
However, this will cause all old blank lines to be ignored, perhaps even some that
were added by hand to improve formatting. So please be cautious when using these
parameters.
-mbl=n --maximum-consecutive-blank-lines=n
This parameter specifies the maximum number of consecutive blank lines which will be
output within code sections of a script. The default is n=1. If the input file has
more than n consecutive blank lines, the number will be reduced to n except as noted
above for the -blbp and -blbs parameters. If n=0 then no blank lines will be output
(unless all old blank lines are retained with the -kbl=2 flag of the next section).
This flag obviously does not apply to pod sections, here-documents, and quotes.
-kbl=n, --keep-old-blank-lines=n
The -kbl=n flag gives you control over how your existing blank lines are treated.
The possible values of n are:
n=0 ignore all old blank lines
n=1 stable: keep old blanks, but limited by the value of the B<-mbl=n> flag
n=2 keep all old blank lines, regardless of the value of the B<-mbl=n> flag
The default is n=1.
-sob, --swallow-optional-blank-lines
This is equivalent to kbl=0 and is included for compatibility with previous versions.
-nsob, --noswallow-optional-blank-lines
This is equivalent to kbl=1 and is included for compatibility with previous versions.
Controls for blank lines around lines of consecutive keywords
The parameters in this section provide some control over the placement of blank lines
within and around groups of statements beginning with selected keywords. These blank
lines are called here keyword group blanks, and all of the parameters begin with
--keyword-group-blanks*, or -kgb* for short. The default settings do not employ these
controls but they can be enabled with the following parameters:
-kgbl=s or --keyword-group-blanks-list=s; s is a quoted string of keywords
-kgbs=s or --keyword-group-blanks-size=s; s gives the number of keywords required to form
a group.
-kgbb=n or --keyword-group-blanks-before=n; n = (0, 1, or 2) controls a leading blank
-kgba=n or --keyword-group-blanks-after=n; n = (0, 1, or 2) controls a trailing blank
-kgbi or --keyword-group-blanks-inside is a switch for adding blanks between subgroups
-kgbd or --keyword-group-blanks-delete is a switch for removing initial blank lines
between keywords
-kgbr=n or --keyword-group-blanks-repeat-count=n can limit the number of times this logic
is applied
In addition, the following abbreviations are available to for simplified usage:
-kgb or --keyword-group-blanks is short for -kgbb=2 -kgba=2 kgbi
-nkgb or --nokeyword-group-blanks, is short for -kgbb=1 -kgba=1 nkgbi
Before describing the meaning of the parameters in detail let us look at an example which
is formatted with default parameter settings.
print "Entering test 2\n";
use Test;
use Encode qw(from_to encode decode
encode_utf8 decode_utf8
find_encoding is_utf8);
use charnames qw(greek);
my @encodings = grep( /iso-?8859/, Encode::encodings() );
my @character_set = ( '0' .. '9', 'A' .. 'Z', 'a' .. 'z' );
my @source = qw(ascii iso8859-1 cp1250);
my @destiny = qw(cp1047 cp37 posix-bc);
my @ebcdic_sets = qw(cp1047 cp37 posix-bc);
my $str = join( '', map( chr($_), 0x20 .. 0x7E ) );
return unless ($str);
using perltidy -kgb gives:
print "Entering test 2\n";
<----------this blank controlled by -kgbb
use Test;
use Encode qw(from_to encode decode
encode_utf8 decode_utf8
find_encoding is_utf8);
use charnames qw(greek);
<---------this blank controlled by -kgbi
my @encodings = grep( /iso-?8859/, Encode::encodings() );
my @character_set = ( '0' .. '9', 'A' .. 'Z', 'a' .. 'z' );
my @source = qw(ascii iso8859-1 cp1250);
my @destiny = qw(cp1047 cp37 posix-bc);
my @ebcdic_sets = qw(cp1047 cp37 posix-bc);
my $str = join( '', map( chr($_), 0x20 .. 0x7E ) );
<----------this blank controlled by -kgba
return unless ($str);
Blank lines have been introduced around the my and use sequences. What happened is that
the default keyword list includes my and use but not print and return. So a continuous
sequence of nine my and use statements was located. This number exceeds the default
threshold of five, so blanks were placed before and after the entire group. Then, since
there was also a subsequence of six my lines, a blank line was introduced to separate
them.
Finer control over blank placement can be achieved by using the individual parameters
rather than the -kgb flag. The individual controls are as follows.
-kgbl=s or --keyword-group-blanks-list=s, where s is a quoted string, defines the set of
keywords which will be formed into groups. The string is a space separated list of
keywords. The default set is s="use require local our my", but any list of keywords may
be used. Comment lines may also be included in a keyword group, even though they are not
keywords. To include ordinary block comments, include the symbol BC. To include static
block comments (which normally begin with '##'), include the symbol SBC.
-kgbs=s or --keyword-group-blanks-size=s, where s is a string describing the number of
consecutive keyword statements forming a group (Note: statements separated by blank lines
in the input file are considered consecutive for purposes of this count). If s is an
integer then it is the minimum number required for a group. A maximum value may also be
given with the format s=min.max, where min is the minimum number and max is the maximum
number, and the min and max values are separated by one or more dots. No groups will be
found if the maximum is less than the minimum. The maximum is unlimited if not given.
The default is s=5. Some examples:
s min max number for group
3 3 unlimited 3 or more
1.1 1 1 1
1..3 1 3 1 to 3
1.0 1 0 (no match)
There is no really good default value for this parameter. If it is set too small, then an
excessive number of blank lines may be generated. However, some users may prefer reducing
the value somewhat below the default, perhaps to s=3.
-kgbb=n or --keyword-group-blanks-before=n specifies whether a blank should appear before
the first line of the group, as follows:
n=0 => (delete) an existing blank line will be removed
n=1 => (stable) no change to the input file is made [DEFAULT]
n=2 => (insert) a blank line is introduced if possible
-kgba=n or --keyword-group-blanks-after=n likewise specifies whether a blank should appear
after the last line of the group, using the same scheme (0=delete, 1=stable, 2=insert).
-kgbi or --keyword-group-blanks-inside controls the insertion of blank lines between the
first and last statement of the entire group. If there is a continuous run of a single
statement type with more than the minimum threshold number (as specified with -kgbs=s)
then this switch causes a blank line be inserted between this subgroup and the others. In
the example above this happened between the use and my statements.
-kgbd or --keyword-group-blanks-delete controls the deletion of any blank lines that exist
in the the group when it is first scanned. When statements are initially scanned, any
existing blank lines are included in the collection. Any such original blank lines will
be deleted before any other insertions are made when the parameter -kgbd is set. The
default is not to do this, -nkgbd.
-kgbr=n or --keyword-group-blanks-repeat-count=n specifies n, the maximum number of times
this logic will be applied to any file. The special value n=0 is the same as n=infinity
which means it will be applied to an entire script [Default]. A value n=1 could be used
to make it apply just one time for example. This might be useful for adjusting just the
use statements in the top part of a module for example.
-kgb or --keyword-group-blanks is an abbreviation equivalent to setting -kgbb=1 -kgba=1
-kgbi. This turns on keyword group formatting with a set of default values.
-nkgb or --nokeyword-group-blanks is equivalent to -kgbb=0 -kgba nkgbi. This flag turns
off keyword group blank lines and is the default setting.
Here are a few notes about the functioning of this technique.
• These parameters are probably more useful as part of a major code reformatting
operation rather than as a routine formatting operation.
In particular, note that deleting old blank lines with -kgbd is an irreversible
operation so it should be applied with care. Existing blank lines may be serving an
important role in controlling vertical alignment.
• Conflicts which arise among these kgb* parameters and other blank line controls are
generally resolved by producing the maximum number of blank lines implied by any
parameter.
For example, if the flags --freeze-blank-lines, or --keep-old-blank-lines=2, are set,
then they have priority over any blank line deletion implied by the -kgb flags of this
section, so no blank lines will be deleted.
For another example, if a keyword group ends at a sub and the flag kgba=0 requests no
blank line there, but we also have --blank-lines-before-subs=2, then two blank lines
will still be introduced before the sub.
• The introduction of blank lines does not occur if it would conflict with other input
controls or code validity. For example, a blank line will not be placed within a here-
doc or within a section of code marked with format skipping comments. And in general,
a blank line will only be introduced at the end of a group if the next statement is a
line of code.
• The count which is used to determine the group size is not the number of lines but
rather the total number of keywords which are found. Individual statements with a
certain leading keyword may continue on multiple lines, but if any of these lines is
nested more than one level deep then that group will be ended.
• The search for groups of lines with similar leading keywords is based on the input
source, not the final formatted source. Consequently, if the source code is badly
formatted, it would be best to make a first formatting pass without these options.
Styles
A style refers to a convenient collection of existing parameters.
-gnu, --gnu-style
-gnu gives an approximation to the GNU Coding Standards (which do not apply to perl)
as they are sometimes implemented. At present, this style overrides the default style
with the following parameters:
-lp -bl -noll -pt=2 -bt=2 -sbt=2 -icp
To use this style with -xlp instead of -lp use -gnu -xlp.
-pbp, --perl-best-practices
-pbp is an abbreviation for the parameters in the book Perl Best Practices by Damian
Conway:
-l=78 -i=4 -ci=4 -st -se -vt=2 -cti=0 -pt=1 -bt=1 -sbt=1 -bbt=1 -nsfs -nolq
-wbb="% + - * / x != == >= <= =~ !~ < > | & =
**= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x="
Please note that this parameter set includes -st and -se flags, which make perltidy
act as a filter on one file only. These can be overridden by placing -nst and/or -nse
after the -pbp parameter.
Also note that the value of continuation indentation, -ci=4, is equal to the value of
the full indentation, -i=4. It is recommended that the either (1) the parameter -ci=2
be used instead, or (2) the flag -xci be set. This will help show structure,
particularly when there are ternary statements. The following snippet illustrates
these options.
# perltidy -pbp
$self->{_text} = (
!$section ? ''
: $type eq 'item' ? "the $section entry"
: "the section on $section"
)
. (
$page
? ( $section ? ' in ' : '' ) . "the $page$page_ext manpage"
: ' elsewhere in this document'
);
# perltidy -pbp -ci=2
$self->{_text} = (
!$section ? ''
: $type eq 'item' ? "the $section entry"
: "the section on $section"
)
. (
$page
? ( $section ? ' in ' : '' ) . "the $page$page_ext manpage"
: ' elsewhere in this document'
);
# perltidy -pbp -xci
$self->{_text} = (
!$section ? ''
: $type eq 'item' ? "the $section entry"
: "the section on $section"
)
. ( $page
? ( $section ? ' in ' : '' ) . "the $page$page_ext manpage"
: ' elsewhere in this document'
);
The -xci flag was developed after the -pbp parameters were published so you need to
include it separately.
One-Line Blocks
A one-line block is a block of code where the contents within the curly braces is short
enough to fit on a single line. For example,
if ( -e $file ) { print "'$file' exists\n" }
The alternative, a block which spans multiple lines, is said to be a broken block. With
few exceptions, perltidy retains existing one-line blocks, if it is possible within the
line-length constraint, but it does not attempt to form new ones. In other words,
perltidy will try to follow the input file regarding broken and unbroken blocks.
The main exception to this rule is that perltidy will attempt to form new one-line blocks
following the keywords "map", "eval", and "sort", "eval", because these code blocks are
often small and most clearly displayed in a single line. This behavior can be controlled
with the flag --one-line-block-exclusion-list described below.
When the cuddled-else style is used, the default treatment of one-line blocks may
interfere with the cuddled style. In this case, the default behavior may be changed with
the flag --cuddled-break-option=n described elsehwere.
When an existing one-line block is longer than the maximum line length, and must therefore
be broken into multiple lines, perltidy checks for and adds any optional terminating
semicolon (unless the -nasc option is used) if the block is a code block.
-olbxl=s, --one-line-block-exclusion-list=s
As noted above, perltidy will, by default, attempt to create new one-line blocks for
certain block types. This flag allows the user to prevent this behavior for the block
types listed in the string s. The list s may include any of the words "sort", "map",
"grep", "eval", or it may be "*" to indicate all of these.
So for example to prevent multi-line eval blocks from becoming one-line blocks, the
command would be -olbxl='eval'. In this case, existing one-line eval blocks will
remain on one-line if possible, and existing multi-line eval blocks will remain multi-
line blocks.
-olbn=n, --one-line-block-nesting=n
Nested one-line blocks are lines with code blocks which themselves contain code
blocks. For example, the following line is a nested one-line block.
foreach (@list) { if ($_ eq $asked_for) { last } ++$found }
The default behavior is to break such lines into multiple lines, but this behavior can
be controlled with this flag. The values of n are:
n=0 break nested one-line blocks into multiple lines [DEFAULT]
n=1 stable: keep existing nested-one line blocks intact
For the above example, the default formatting (-olbn=0) is
foreach (@list) {
if ( $_ eq $asked_for ) { last }
++$found;
}
If the parameter -olbn=1 is given, then the line will be left intact if it is a single
line in the source, or it will be broken into multiple lines if it is broken in
multiple lines in the source.
-olbs=n, --one-line-block-semicolons=n
This flag controls the placement of semicolons at the end of one-line blocks.
Semicolons are optional before a closing block brace, and frequently they are omitted
at the end of a one-line block containing just a single statement. By default,
perltidy follows the input file regarding these semicolons, but this behavior can be
controlled by this flag. The values of n are:
n=0 remove terminal semicolons in one-line blocks having a single statement
n=1 stable; keep input file placement of terminal semicolons [DEFAULT ]
n=2 add terminal semicolons in all one-line blocks
Note that the n=2 option has no effect if adding semicolons is prohibited with the
-nasc flag. Also not that while n=2 adds missing semicolons to all one-line blocks,
regardless of complexity, the n=0 option only removes ending semicolons which
terminate one-line blocks containing just one semicolon. So these two options are not
exact inverses.
Forming new one-line blocks
Sometimes it might be desirable to convert a script to have one-line blocks whenever
possible. Although there is currently no flag for this, a simple workaround is to
execute perltidy twice, once with the flag -noadd-newlines and then once again with
normal parameters, like this:
cat infile | perltidy -nanl | perltidy >outfile
When executed on this snippet
if ( $? == -1 ) {
die "failed to execute: $!\n";
}
if ( $? == -1 ) {
print "Had enough.\n";
die "failed to execute: $!\n";
}
the result is
if ( $? == -1 ) { die "failed to execute: $!\n"; }
if ( $? == -1 ) {
print "Had enough.\n";
die "failed to execute: $!\n";
}
This shows that blocks with a single statement become one-line blocks.
Breaking existing one-line blocks
There is no automatic way to break existing long one-line blocks into multiple lines,
but this can be accomplished by processing a script, or section of a script, with a
short value of the parameter maximum-line-length=n. Then, when the script is
reformatted again with the normal parameters, the blocks which were broken will remain
broken (with the exceptions noted above).
Another trick for doing this for certain block types is to format one time with the
-cuddled-else flag and --cuddled-break-option=2. Then format again with the normal
parameters. This will break any one-line blocks which are involved in a cuddled-else
style.
Controlling Vertical Alignment
Vertical alignment refers to lining up certain symbols in a list of consecutive similar
lines to improve readability. For example, the "fat commas" are aligned in the following
statement:
$data = $pkg->new(
PeerAddr => join( ".", @port[ 0 .. 3 ] ),
PeerPort => $port[4] * 256 + $port[5],
Proto => 'tcp'
);
Vertical alignment can be completely turned off using the -novalign flag mentioned below.
However, vertical alignment can be forced to stop and restart by selectively introducing
blank lines. For example, a blank has been inserted in the following code to keep
somewhat similar things aligned.
%option_range = (
'format' => [ 'tidy', 'html', 'user' ],
'output-line-ending' => [ 'dos', 'win', 'mac', 'unix' ],
'character-encoding' => [ 'none', 'utf8' ],
'block-brace-tightness' => [ 0, 2 ],
'brace-tightness' => [ 0, 2 ],
'paren-tightness' => [ 0, 2 ],
'square-bracket-tightness' => [ 0, 2 ],
);
Vertical alignment is implemented by locally increasing an existing blank space to produce
alignment with an adjacent line. It cannot occur if there is no blank space to increase.
So if a particular space is removed by one of the existing controls then vertical
alignment cannot occur. Likewise, if a space is added with one of the controls, then
vertical alignment might occur.
For example,
# perltidy -nwls='=>'
$data = $pkg->new(
PeerAddr=> join( ".", @port[ 0 .. 3 ] ),
PeerPort=> $port[4] * 256 + $port[5],
Proto=> 'tcp'
);
Completely turning off vertical alignment with -novalign
The default is to use vertical alignment, but vertical alignment can be completely
turned of with the -novalign flag.
A lower level of control of vertical alignment is possible with three parameters -vc,
-vsc, and -vbc. These independently control alignment of code, side comments and block
comments. They are described in the next section.
The parameter -valign is in fact an alias for -vc -vsc -vbc, and its negative
-novalign is an alias for -nvc -nvsc -nvbc.
Controlling code alignment with --valign-code or -vc
The -vc flag enables alignment of code symbols such as =. The default is -vc. For
detailed control of which symbols to align, see the -valign-exclude-list parameter
below.
Controlling side comment alignment with --valign-side-comments or -vsc
The -vsc flag enables alignment of side comments and is enabled by default. If side
comment alignment is disabled with -nvsc they will appear at a fixed space from the
preceding code token. The default is -vsc
Controlling block comment alignment with --valign-block-comments or -vbc
When -vbc is enabled, block comments can become aligned for example if one comment of
a consecutive sequence of comments becomes outdented due a length in excess of the
maximum line length. If this occurs, the entire group of comments will remain aligned
and be outdented by the same amount. This coordinated alignment will not occur if
-nvbc is set. The default is -vbc.
Finer alignment control with --valign-exclusion-list=s or -vxl=s and
--valign-inclusion-list=s or -vil=s
More detailed control of alignment types is available with these two parameters. Most
of the vertical alignments in typical programs occur at one of the tokens ',', '=',
and '=>', but many other alignments are possible and are given in the following list:
= **= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x=
{ ( ? : , ; => && || ~~ !~~ =~ !~ // <=> -> q
if unless and or err for foreach while until
These alignment types correspond to perl symbols, operators and keywords except for
'q', which refers to the special case of alignment in a 'use' statement of qw quotes
and empty parens.
They are all enabled by default, but they can be selectively disabled by including one
or more of these tokens in the space-separated list valign-exclusion-list=s. For
example, the following would prevent alignment at = and if:
--valign-exclusion-list='= if'
If it is simpler to specify only the token types which are to be aligned, then include
the types which are to be aligned in the list of --valign-inclusion-list. In that
case you may leave the valign-exclusion-list undefined, or use the special symbol *
for the exclusion list. For example, the following parameters enable alignment only
at commas and 'fat commas':
--valign-inclusion-list=', =>'
--valign-exclusion-list='*' ( this is optional and may be omitted )
These parameter lists should consist of space-separated tokens from the above list of
possible alignment tokens, or a '*'. If an unrecognized token appears, it is simply
ignored. And if a specific token is entered in both lists by mistake then the
exclusion list has priority.
The default values of these parameters enable all alignments and are equivalent to
--valign-exclusion-list=' '
--valign-inclusion-list='*'
To illustrate, consider the following snippet with default formatting
# perltidy
$co_description = ($color) ? 'bold cyan' : ''; # description
$co_prompt = ($color) ? 'bold green' : ''; # prompt
$co_unused = ($color) ? 'on_green' : 'reverse'; # unused
To exclude all alignments except the equals (i.e., include only equals) we could use:
# perltidy -vil='='
$co_description = ($color) ? 'bold cyan' : ''; # description
$co_prompt = ($color) ? 'bold green' : ''; # prompt
$co_unused = ($color) ? 'on_green' : 'reverse'; # unused
To exclude only the equals we could use:
# perltidy -vxl='='
$co_description = ($color) ? 'bold cyan' : ''; # description
$co_prompt = ($color) ? 'bold green' : ''; # prompt
$co_unused = ($color) ? 'on_green' : 'reverse'; # unused
Notice in this last example that although only the equals alignment was excluded, the
ternary alignments were also lost. This happens because the vertical aligner sweeps
from left-to-right and usually stops if an important alignment cannot be made for some
reason.
But also notice that side comments remain aligned because their alignment is
controlled separately with the parameter --valign-side_comments described above.
Extended Syntax
This section describes some parameters for dealing with extended syntax.
For another method of handling extended syntax see the section "Skipping Selected Sections
of Code".
Also note that the module Perl::Tidy supplies a pre-filter and post-filter capability.
This requires calling the module from a separate program rather than through the binary
perltidy.
-xs, --extended-syntax
This flag allows perltidy to handle certain common extensions to the standard syntax
without complaint.
For example, without this flag a structure such as the following would generate a
syntax error:
Method deposit( Num $amount) {
$self->balance( $self->balance + $amount );
}
This flag is enabled by default but it can be deactivated with -nxs. Probably the
only reason to deactivate this flag is to generate more diagnostic messages when
debugging a script.
-sal=s, --sub-alias-list=s
This flag causes one or more words to be treated the same as if they were the keyword
sub. The string s contains one or more alias words, separated by spaces or commas.
For example,
perltidy -sal='method fun _sub M4'
will cause the perltidy to treat the words 'method', 'fun', '_sub' and 'M4' the same
as if they were 'sub'. Note that if the alias words are separated by spaces then the
string of words should be placed in quotes.
Note that several other parameters accept a list of keywords, including 'sub' (see
"Specifying Block Types"). You do not need to include any sub aliases in these lists.
Just include keyword 'sub' if you wish, and all aliases are automatically included.
-gal=s, --grep-alias-list=s
This flag allows a code block following an external 'list operator' function to be
formatted as if it followed one of the built-in keywords grep, map or sort. The
string s contains the names of one or more such list operators, separated by spaces or
commas.
By 'list operator' is meant a function which is invoked in the form
word {BLOCK} @list
Perltidy tries to keep code blocks for these functions intact, since they are usually
short, and does not automatically break after the closing brace since a list may
follow. It also does some special handling of continuation indentation.
For example, the code block arguments to functions 'My_grep' and 'My_map' can be given
formatting like 'grep' with
perltidy -gal='My_grep My_map'
By default, the following list operators in List::Util are automatically included:
all any first none notall reduce reductions
Any operators specified with --grep-alias-list are added to this list. The next
parameter can be used to remove words from this default list.
-gaxl=s, --grep-alias-exclusion-list=s
The -gaxl=s flag provides a method for removing any of the default list operators
given above by listing them in the string s. To remove all of the default operators
use -gaxl='*'.
-uf=s, --use-feature=s
This flag tells perltidy to allow the syntax associated a pragma in string s.
Currently only the recognized values for the string are s='class' or string s=' '.
The default is --use-feature='class'. This enables perltidy to recognized the special
words class, method, field, and ADJUST. If this causes a conflict with other uses of
these words, the default can be turned off with --use-feature=' '.
Other Controls
Deleting selected text
Perltidy can selectively delete comments and/or pod documentation. The command -dac
or --delete-all-comments will delete all comments and all pod documentation, leaving
just code and any leading system control lines.
The command -dp or --delete-pod will remove all pod documentation (but not comments).
Two commands which remove comments (but not pod) are: -dbc or --delete-block-comments
and -dsc or --delete-side-comments. (Hanging side comments will be deleted with side
comments here.)
When side comments are deleted, any special control side comments for non-indenting
braces will be retained unless they are deactivated with a -nnib flag.
The negatives of these commands also work, and are the defaults. When block comments
are deleted, any leading 'hash-bang' will be retained. Also, if the -x flag is used,
any system commands before a leading hash-bang will be retained (even if they are in
the form of comments).
Writing selected text to a file
When perltidy writes a formatted text file, it has the ability to also send selected
text to a file with a .TEE extension. This text can include comments and pod
documentation.
The command -tac or --tee-all-comments will write all comments and all pod
documentation.
The command -tp or --tee-pod will write all pod documentation (but not comments).
The commands which write comments (but not pod) are: -tbc or --tee-block-comments and
-tsc or --tee-side-comments. (Hanging side comments will be written with side
comments here.)
The negatives of these commands also work, and are the defaults.
Using a .perltidyrc command file
If you use perltidy frequently, you probably won't be happy until you create a
.perltidyrc file to avoid typing commonly-used parameters. Perltidy will first look
in your current directory for a command file named .perltidyrc. If it does not find
one, it will continue looking for one in other standard locations.
These other locations are system-dependent, and may be displayed with the command
"perltidy -dpro". Under Unix systems, it will first look for an environment variable
PERLTIDY. Then it will look for a .perltidyrc file in the home directory, and then
for a system-wide file /usr/local/etc/perltidyrc, and then it will look for
/etc/perltidyrc. Note that these last two system-wide files do not have a leading
dot. Further system-dependent information will be found in the INSTALL file
distributed with perltidy.
Under Windows, perltidy will also search for a configuration file named perltidy.ini
since Windows does not allow files with a leading period (.). Use "perltidy -dpro" to
see the possible locations for your system. An example might be C:\Documents and
Settings\All Users\perltidy.ini.
Another option is the use of the PERLTIDY environment variable. The method for
setting environment variables depends upon the version of Windows that you are using.
Instructions for Windows 95 and later versions can be found here:
http://www.netmanage.com/000/20021101_005_tcm21-6336.pdf
Under Windows NT / 2000 / XP the PERLTIDY environment variable can be placed in either
the user section or the system section. The later makes the configuration file common
to all users on the machine. Be sure to enter the full path of the configuration file
in the value of the environment variable. Ex. PERLTIDY=C:\Documents and
Settings\perltidy.ini
The configuration file is free format, and simply a list of parameters, just as they
would be entered on a command line. Any number of lines may be used, with any number
of parameters per line, although it may be easiest to read with one parameter per
line. Comment text begins with a #, and there must also be a space before the # for
side comments. It is a good idea to put complex parameters in either single or double
quotes.
Here is an example of a .perltidyrc file:
# This is a simple of a .perltidyrc configuration file
# This implements a highly spaced style
-se # errors to standard error output
-w # show all warnings
-bl # braces on new lines
-pt=0 # parens not tight at all
-bt=0 # braces not tight
-sbt=0 # square brackets not tight
The parameters in the .perltidyrc file are installed first, so any parameters given on
the command line will have priority over them.
To avoid confusion, perltidy ignores any command in the .perltidyrc file which would
cause some kind of dump and an exit. These are:
-h -v -ddf -dln -dop -dsn -dtt -dwls -dwrs -ss
There are several options may be helpful in debugging a .perltidyrc file:
• A very helpful command is --dump-profile or -dpro. It writes a list of all
configuration filenames tested to standard output, and if a file is found, it
dumps the content to standard output before exiting. So, to find out where
perltidy looks for its configuration files, and which one if any it selects, just
enter
perltidy -dpro
• It may be simplest to develop and test configuration files with alternative names,
and invoke them with -pro=filename on the command line. Then rename the desired
file to .perltidyrc when finished.
• The parameters in the .perltidyrc file can be switched off with the -npro option.
• The commands --dump-options, --dump-defaults, --dump-long-names, and
--dump-short-names, all described below, may all be helpful.
Creating a new abbreviation
A special notation is available for use in a .perltidyrc file for creating an
abbreviation for a group of options. This can be used to create a shorthand for one
or more styles which are frequently, but not always, used. The notation is to group
the options within curly braces which are preceded by the name of the alias (without
leading dashes), like this:
newword {
-opt1
-opt2
}
where newword is the abbreviation, and opt1, etc, are existing parameters or other
abbreviations. The main syntax requirement is that the new abbreviation along with
its opening curly brace must begin on a new line. Space before and after the curly
braces is optional.
For a specific example, the following line
oneliner { --maximum-line-length=0 --noadd-newlines --noadd-terminal-newline}
or equivalently with abbreviations
oneliner { -l=0 -nanl -natnl }
could be placed in a .perltidyrc file to temporarily override the maximum line length
with a large value, to temporarily prevent new line breaks from being added, and to
prevent an extra newline character from being added the file. All other settings in
the .perltidyrc file still apply. Thus it provides a way to format a long 'one liner'
when perltidy is invoked with
perltidy --oneliner ...
(Either "-oneliner" or "--oneliner" may be used).
Skipping leading non-perl commands with -x or --look-for-hash-bang
If your script has leading lines of system commands or other text which are not valid
perl code, and which are separated from the start of the perl code by a "hash-bang"
line, ( a line of the form "#!...perl" ), you must use the -x flag to tell perltidy
not to parse and format any lines before the "hash-bang" line. This option also
invokes perl with a -x flag when checking the syntax. This option was originally
added to allow perltidy to parse interactive VMS scripts, but it should be used for
any script which is normally invoked with "perl -x".
Please note: do not use this flag unless you are sure your script needs it. Parsing
errors can occur if it does not have a hash-bang, or, for example, if the actual first
hash-bang is in a here-doc. In that case a parsing error will occur because the
tokenization will begin in the middle of the here-doc.
Making a file unreadable
The goal of perltidy is to improve the readability of files, but there are two
commands which have the opposite effect, --mangle and --extrude. They are actually
merely aliases for combinations of other parameters. Both of these strip all possible
whitespace, but leave comments and pod documents, so that they are essentially
reversible. The difference between these is that --mangle puts the fewest possible
line breaks in a script while --extrude puts the maximum possible. Note that these
options do not provided any meaningful obfuscation, because perltidy can be used to
reformat the files. They were originally developed to help test the tokenization
logic of perltidy, but they have other uses. One use for --mangle is the following:
perltidy --mangle myfile.pl -st | perltidy -o myfile.pl.new
This will form the maximum possible number of one-line blocks (see next section), and
can sometimes help clean up a badly formatted script.
A similar technique can be used with --extrude instead of --mangle to make the minimum
number of one-line blocks.
Another use for --mangle is to combine it with -dac to reduce the file size of a perl
script.
Debugging
The following flags are available for debugging:
--dump-cuddled-block-list or -dcbl will dump to standard output the internal hash of
cuddled block types created by a -cuddled-block-list input string.
--dump-defaults or -ddf will write the default option set to standard output and quit
--dump-profile or -dpro will write the name of the current configuration file and its
contents to standard output and quit.
--dump-options or -dop will write current option set to standard output and quit.
--dump-long-names or -dln will write all command line long names (passed to
Get_options) to standard output and quit.
--dump-short-names or -dsn will write all command line short names to standard output
and quit.
--dump-token-types or -dtt will write a list of all token types to standard output
and quit.
--dump-want-left-space or -dwls will write the hash %want_left_space to standard
output and quit. See the section on controlling whitespace around tokens.
--dump-want-right-space or -dwrs will write the hash %want_right_space to standard
output and quit. See the section on controlling whitespace around tokens.
--no-memoize or -nmem will turn of memoizing. Memoization can reduce run time when
running perltidy repeatedly in a single process. It is on by default but can be
deactivated for testing with -nmem.
--no-timestamp or -nts will eliminate any time stamps in output files to prevent
differences in dates from causing test installation scripts to fail. There are just a
couple of places where timestamps normally occur. One is in the headers of html files,
and another is when the -cscw option is selected. The default is to allow timestamps
(--timestamp or -ts).
--file-size-order or -fso will cause files to be processed in order of increasing
size, when multiple files are being processed. This is useful during program
development, when large numbers of files with varying sizes are processed, because it
can reduce virtual memory usage.
--maximum-file-size-mb=n or -maxfs=n specifies the maximum file size in megabytes that
perltidy will attempt to format. This parameter is provided to avoid causing system
problems by accidentally attempting to format an extremely large data file. Most perl
scripts are less than about 2 MB in size. The integer n has a default value of 10, so
perltidy will skip formatting files which have a size greater than 10 MB. The command
to increase the limit to 20 MB for example would be
perltidy -maxfs=20
This only applies to files specified by filename on the command line.
--maximum-level-errors=n or -maxle=n specifies the maximum number of indentation level
errors are allowed before perltidy skips formatting and just outputs a file verbatim.
The default is n=1. This means that if the final indentation of a script differs from
the starting indentation by more than 1 levels, the file will be output verbatim. To
avoid formatting if there are any indentation level errors use -maxle=0. To skip this
check you can either set n equal to a large number, such as n=100, or set n=-1.
For example, the following script has level error of 3 and will be output verbatim
Input and default output:
{{{
perltidy -maxle=100
{
{
{
--maximum-unexpected-errors=n or -maxue=n specifies the maximum number of unexpected
tokenization errors are allowed before formatting is skipped and a script is output
verbatim. The intention is to avoid accidentally formatting a non-perl script, such
as an html file for example. This check can be turned off by setting n=0.
A recommended value is n=3. However, the default is n=0 (skip this check) to avoid
causing problems with scripts which have extended syntaxes.
-DEBUG will write a file with extension .DEBUG for each input file showing the
tokenization of all lines of code.
Making a table of information on code blocks
A table listing information about the blocks of code in a file can be made with
--dump-block-summary, or -dbs. This causes perltidy to read and parse the file, write
a table of comma-separated values for selected code blocks to the standard output, and
then exit. This parameter must be on the command line, not in a .perlticyrc file, and
it requires a single file name on the command line. For example
perltidy -dbs somefile.pl >blocks.csv
produces an output file blocks.csv whose lines hold these parameters:
filename - the name of the file
line - the line number of the opening brace of this block
line_count - the number of lines between opening and closing braces
code_lines - the number of lines excluding blanks, comments, and pod
type - the block type (sub, for, foreach, ...)
name - the block name if applicable (sub name, label, asub name)
depth - the nesting depth of the opening block brace
max_change - the change in depth to the most deeply nested code block
block_count - the total number of code blocks nested in this block
mccabe_count - the McCabe complexity measure of this code block
This feature was developed to help identify complex sections of code as an aid in
refactoring. The McCabe complexity measure follows the definition used by
Perl::Critic. By default the table contains these values for subroutines, but the
user may request them for any or all blocks of code or packages. For blocks which are
loops nested within loops, a postfix '+' to the "type" is added to indicate possible
code complexity. Although the table does not otherwise indicate which blocks are
nested in other blocks, this can be determined by computing and comparing the block
ending line numbers.
By default the table lists subroutines with more than 20 "code_lines", but this can be
changed with the following two parameters:
--dump-block-minimum-lines=n, or -dbl=n, where n is the minimum number of "code_lines"
to be included. The default is -n=20. Note that "code_lines" is the number of lines
excluding and comments, blanks and pod.
--dump-block-types=s, or -dbt=s, where string s is a list of block types to be
included. The type of a block is either the name of the perl builtin keyword for that
block (such as sub if elsif else for foreach ..) or the word immediately before the
opening brace. In addition, there are a few symbols for special block types, as
follows:
if elsif else for foreach ... any keyword introducing a block
sub - any sub or anynomous sub
asub - any anonymous sub
* - any block except nameless blocks
+ - any nested inner block loop
package - any package or class
closure - any nameless block
In addition, specific block loop types which are nested in other loops can be selected
by adding a + after the block name. (Nested loops are sometimes good candidates for
restructuring).
The default is -dbt='sub'.
In the following examples a table "block.csv" is created for a file "somefile.pl":
• This selects both "subs" and "packages" which have 20 or more lines of code. This
can be useful in code which contains multiple packages.
perltidy -dbs -dbt='sub package' somefile.pl >blocks.csv
• This selects block types "sub for foreach while" with 10 or more code lines.
perltidy -dbs -dbl=10 -dbt='sub for foreach while' somefile.pl >blocks.csv
• This selects blocks with 2 or more code lines which are type "sub" or which are
inner loops.
perltidy -dbs -dbl=2 -dbt='sub +' somefile.pl >blocks.csv
• This selects every block and package.
perltidy -dbs -dbl=1 -dbt='* closure' somefile.pl >blocks.csv
Working with MakeMaker, AutoLoader and SelfLoader
The first $VERSION line of a file which might be eval'd by MakeMaker is passed through
unchanged except for indentation. Use --nopass-version-line, or -npvl, to deactivate
this feature.
If the AutoLoader module is used, perltidy will continue formatting code after seeing
an __END__ line. Use --nolook-for-autoloader, or -nlal, to deactivate this feature.
Likewise, if the SelfLoader module is used, perltidy will continue formatting code
after seeing a __DATA__ line. Use --nolook-for-selfloader, or -nlsl, to deactivate
this feature.
Working around problems with older version of Perl
Perltidy contains a number of rules which help avoid known subtleties and problems
with older versions of perl, and these rules always take priority over whatever
formatting flags have been set. For example, perltidy will usually avoid starting a
new line with a bareword, because this might cause problems if "use strict" is active.
There is no way to override these rules.
HTML OPTIONS
The -html master switch
The flag -html causes perltidy to write an html file with extension .html. So, for
example, the following command
perltidy -html somefile.pl
will produce a syntax-colored html file named somefile.pl.html which may be viewed
with a browser.
Please Note: In this case, perltidy does not do any formatting to the input file, and
it does not write a formatted file with extension .tdy. This means that two perltidy
runs are required to create a fully reformatted, html copy of a script.
The -pre flag for code snippets
When the -pre flag is given, only the pre-formatted section, within the <PRE> and
</PRE> tags, will be output. This simplifies inclusion of the output in other files.
The default is to output a complete web page.
The -nnn flag for line numbering
When the -nnn flag is given, the output lines will be numbered.
The -toc, or --html-table-of-contents flag
By default, a table of contents to packages and subroutines will be written at the
start of html output. Use -ntoc to prevent this. This might be useful, for example,
for a pod document which contains a number of unrelated code snippets. This flag only
influences the code table of contents; it has no effect on any table of contents
produced by pod2html (see next item).
The -pod, or --pod2html flag
There are two options for formatting pod documentation. The default is to pass the
pod through the Pod::Html module (which forms the basis of the pod2html utility). Any
code sections are formatted by perltidy, and the results then merged. Note: perltidy
creates a temporary file when Pod::Html is used; see "FILES". Also, Pod::Html creates
temporary files for its cache.
NOTE: Perltidy counts the number of "=cut" lines, and either moves the pod text to the
top of the html file if there is one "=cut", or leaves the pod text in its original
order (interleaved with code) otherwise.
Most of the flags accepted by pod2html may be included in the perltidy command line,
and they will be passed to pod2html. In some cases, the flags have a prefix "pod" to
emphasize that they are for the pod2html, and this prefix will be removed before they
are passed to pod2html. The flags which have the additional "pod" prefix are:
--[no]podheader --[no]podindex --[no]podrecurse --[no]podquiet
--[no]podverbose --podflush
The flags which are unchanged from their use in pod2html are:
--backlink=s --cachedir=s --htmlroot=s --libpods=s --title=s
--podpath=s --podroot=s
where 's' is an appropriate character string. Not all of these flags are available in
older versions of Pod::Html. See your Pod::Html documentation for more information.
The alternative, indicated with -npod, is not to use Pod::Html, but rather to format
pod text in italics (or whatever the stylesheet indicates), without special html
markup. This is useful, for example, if pod is being used as an alternative way to
write comments.
The -frm, or --frames flag
By default, a single html output file is produced. This can be changed with the -frm
option, which creates a frame holding a table of contents in the left panel and the
source code in the right side. This simplifies code browsing. Assume, for example,
that the input file is MyModule.pm. Then, for default file extension choices, these
three files will be created:
MyModule.pm.html - the frame
MyModule.pm.toc.html - the table of contents
MyModule.pm.src.html - the formatted source code
Obviously this file naming scheme requires that output be directed to a real file (as
opposed to, say, standard output). If this is not the case, or if the file extension
is unknown, the -frm option will be ignored.
The -text=s, or --html-toc-extension flag
Use this flag to specify the extra file extension of the table of contents file when
html frames are used. The default is "toc". See "Specifying File Extensions".
The -sext=s, or --html-src-extension flag
Use this flag to specify the extra file extension of the content file when html frames
are used. The default is "src". See "Specifying File Extensions".
The -hent, or --html-entities flag
This flag controls the use of Html::Entities for html formatting. By default, the
module Html::Entities is used to encode special symbols. This may not be the right
thing for some browser/language combinations. Use --nohtml-entities or -nhent to
prevent this.
Style Sheets
Style sheets make it very convenient to control and adjust the appearance of html
pages. The default behavior is to write a page of html with an embedded style sheet.
An alternative to an embedded style sheet is to create a page with a link to an
external style sheet. This is indicated with the -css=filename, where the external
style sheet is filename. The external style sheet filename will be created if and
only if it does not exist. This option is useful for controlling multiple pages from
a single style sheet.
To cause perltidy to write a style sheet to standard output and exit, use the -ss, or
--stylesheet, flag. This is useful if the style sheet could not be written for some
reason, such as if the -pre flag was used. Thus, for example,
perltidy -html -ss >mystyle.css
will write a style sheet with the default properties to file mystyle.css.
The use of style sheets is encouraged, but a web page without a style sheets can be
created with the flag -nss. Use this option if you must to be sure that older
browsers (roughly speaking, versions prior to 4.0 of Netscape Navigator and Internet
Explorer) can display the syntax-coloring of the html files.
Controlling HTML properties
Note: It is usually more convenient to accept the default properties and then edit the
stylesheet which is produced. However, this section shows how to control the
properties with flags to perltidy.
Syntax colors may be changed from their default values by flags of the either the long
form, -html-color-xxxxxx=n, or more conveniently the short form, -hcx=n, where xxxxxx
is one of the following words, and x is the corresponding abbreviation:
Token Type xxxxxx x
---------- -------- --
comment comment c
number numeric n
identifier identifier i
bareword, function bareword w
keyword keyword k
quite, pattern quote q
here doc text here-doc-text h
here doc target here-doc-target hh
punctuation punctuation pu
parentheses paren p
structural braces structure s
semicolon semicolon sc
colon colon co
comma comma cm
label label j
sub definition name subroutine m
pod text pod-text pd
A default set of colors has been defined, but they may be changed by providing values
to any of the following parameters, where n is either a 6 digit hex RGB color value or
an ascii name for a color, such as 'red'.
To illustrate, the following command will produce an html file somefile.pl.html with
"aqua" keywords:
perltidy -html -hck=00ffff somefile.pl
and this should be equivalent for most browsers:
perltidy -html -hck=aqua somefile.pl
Perltidy merely writes any non-hex names that it sees in the html file. The following
16 color names are defined in the HTML 3.2 standard:
black => 000000,
silver => c0c0c0,
gray => 808080,
white => ffffff,
maroon => 800000,
red => ff0000,
purple => 800080,
fuchsia => ff00ff,
green => 008000,
lime => 00ff00,
olive => 808000,
yellow => ffff00
navy => 000080,
blue => 0000ff,
teal => 008080,
aqua => 00ffff,
Many more names are supported in specific browsers, but it is safest to use the hex
codes for other colors. Helpful color tables can be located with an internet search
for "HTML color tables".
Besides color, two other character attributes may be set: bold, and italics. To set a
token type to use bold, use the flag --html-bold-xxxxxx or -hbx, where xxxxxx or x are
the long or short names from the above table. Conversely, to set a token type to NOT
use bold, use --nohtml-bold-xxxxxx or -nhbx.
Likewise, to set a token type to use an italic font, use the flag --html-italic-xxxxxx
or -hix, where again xxxxxx or x are the long or short names from the above table.
And to set a token type to NOT use italics, use --nohtml-italic-xxxxxx or -nhix.
For example, to use bold braces and lime color, non-bold, italics keywords the
following command would be used:
perltidy -html -hbs -hck=00FF00 -nhbk -hik somefile.pl
The background color can be specified with --html-color-background=n, or -hcbg=n for
short, where n is a 6 character hex RGB value. The default color of text is the value
given to punctuation, which is black as a default.
Here are some notes and hints:
1. If you find a preferred set of these parameters, you may want to create a
.perltidyrc file containing them. See the perltidy man page for an explanation.
2. Rather than specifying values for these parameters, it is probably easier to accept
the defaults and then edit a style sheet. The style sheet contains comments which
should make this easy.
3. The syntax-colored html files can be very large, so it may be best to split large
files into smaller pieces to improve download times.
SOME COMMON INPUT CONVENTIONS
Specifying Block Types
Several parameters which refer to code block types may be customized by also specifying an
associated list of block types. The type of a block is the name of the keyword which
introduces that block, such as if, else, or sub. An exception is a labeled block, which
has no keyword, and should be specified with just a colon. To specify all blocks use '*'.
The keyword sub indicates a named sub. For anonymous subs, use the special keyword asub.
For example, the following parameter specifies "sub", labels, "BEGIN", and "END" blocks:
-cscl="sub : BEGIN END"
(the meaning of the -cscl parameter is described above.) Note that quotes are required
around the list of block types because of the spaces. For another example, the following
list specifies all block types for vertical tightness:
-bbvtl='*'
Specifying File Extensions
Several parameters allow default file extensions to be overridden. For example, a backup
file extension may be specified with -bext=ext, where ext is some new extension. In order
to provides the user some flexibility, the following convention is used in all cases to
decide if a leading '.' should be used. If the extension "ext" begins with "A-Z", "a-z",
or "0-9", then it will be appended to the filename with an intermediate '.' (or perhaps a
'_' on VMS systems). Otherwise, it will be appended directly.
For example, suppose the file is somefile.pl. For "-bext=old", a '.' is added to give
somefile.pl.old. For "-bext=.old", no additional '.' is added, so again the backup file
is somefile.pl.old. For "-bext=~", then no dot is added, and the backup file will be
somefile.pl~ .
SWITCHES WHICH MAY BE NEGATED
The following list shows all short parameter names which allow a prefix 'n' to produce the
negated form:
D anl asbl asc ast asu atc atnl aws b
baa baao bar bbao bbb bbc bbs bl bli boa
boc bok bol bom bos bot cblx ce conv cpb
cs csc cscb cscw dac dbc dbs dcbl dcsc ddf
dln dnl dop dp dpro drc dsc dsm dsn dtc
dtt dwic dwls dwrs dws eos f fll fpva frm
fs fso gcs hbc hbcm hbco hbh hbhh hbi hbj
hbk hbm hbn hbp hbpd hbpu hbq hbs hbsc hbv
hbw hent hic hicm hico hih hihh hii hij hik
him hin hip hipd hipu hiq his hisc hiv hiw
hsc html ibc icb icp iob isbc iscl kgb kgbd
kgbi kis lal log lop lp lsl mem nib ohbr
okw ola olc oll olq opr opt osbc osbr otr
ple pod pvl q sac sbc sbl scbb schb scp
scsb sct se sfp sfs skp sob sobb sohb sop
sosb sot ssc st sts t tac tbc toc tp
tqw trp ts tsc tso vbc vc vmll vsc w
wfc wn x xci xlp xs
Equivalently, the prefix 'no' or 'no-' on the corresponding long names may be used.
LIMITATIONS
Parsing Limitations
Perltidy should work properly on most perl scripts. It does a lot of self-checking,
but still, it is possible that an error could be introduced and go undetected.
Therefore, it is essential to make careful backups and to test reformatted scripts.
The main current limitation is that perltidy does not scan modules included with 'use'
statements. This makes it necessary to guess the context of any bare words introduced
by such modules. Perltidy has good guessing algorithms, but they are not infallible.
When it must guess, it leaves a message in the log file.
If you encounter a bug, please report it.
What perltidy does not parse and format
Perltidy indents but does not reformat comments and "qw" quotes. Perltidy does not in
any way modify the contents of here documents or quoted text, even if they contain
source code. (You could, however, reformat them separately). Perltidy does not
format 'format' sections in any way. And, of course, it does not modify pod
documents.
FILES
Temporary files
Under the -html option with the default --pod2html flag, a temporary file is required
to pass text to Pod::Html. Unix systems will try to use the POSIX tmpnam() function.
Otherwise the file perltidy.TMP will be temporarily created in the current working
directory.
Special files when standard input is used
When standard input is used, the log file, if saved, is perltidy.LOG, and any errors
are written to perltidy.ERR unless the -se flag is set. These are saved in the
current working directory.
Files overwritten
The following file extensions are used by perltidy, and files with these extensions
may be overwritten or deleted: .ERR, .LOG, .TEE, and/or .tdy, .html, and .bak,
depending on the run type and settings.
Files extensions limitations
Perltidy does not operate on files for which the run could produce a file with a
duplicated file extension. These extensions include .LOG, .ERR, .TEE, and perhaps
.tdy and .bak, depending on the run type. The purpose of this rule is to prevent
generating confusing filenames such as somefile.tdy.tdy.tdy.
ERROR HANDLING
An exit value of 0, 1, or 2 is returned by perltidy to indicate the status of the result.
A exit value of 0 indicates that perltidy ran to completion with no error messages.
A non-zero exit value indicates some kind of problem was detected.
An exit value of 1 indicates that perltidy terminated prematurely, usually due to some
kind of errors in the input parameters. This can happen for example if a parameter is
misspelled or given an invalid value. Error messages in the standard error output will
indicate the cause of any problem. If perltidy terminates prematurely then no output
files will be produced.
An exit value of 2 indicates that perltidy was able to run to completion but there there
are (1) warning messages in the standard error output related to parameter errors or
problems and/or (2) warning messages in the perltidy error file(s) relating to possible
syntax errors in one or more of the source script(s) being tidied. When multiple files
are being processed, an error detected in any single file will produce this type of exit
condition.
SEE ALSO
perlstyle(1), Perl::Tidy(3)
INSTALLATION
The perltidy binary uses the Perl::Tidy module and is installed when that module is
installed. The module name is case-sensitive. For example, the basic command for
installing with cpanm is 'cpanm Perl::Tidy'.
VERSION
This man page documents perltidy version 20230309
BUG REPORTS
The source code repository is at <https://github.com/perltidy/perltidy>.
To report a new bug or problem, use the "issues" link on this page.
COPYRIGHT
Copyright (c) 2000-2022 by Steve Hancock
LICENSE
This package is free software; you can redistribute it and/or modify it under the terms of
the "GNU General Public License".
Please refer to the file "COPYING" for details.
DISCLAIMER
This package is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the "GNU General Public License" for more details.