Provided by: libstring-errf-perl_0.009-1_all 
NAME
String::Errf - a simple sprintf-like dialect
VERSION
version 0.009
SYNOPSIS
use String::Errf qw(errf);
print errf "This process was started at %{start}t with %{args;argument}n.\n",
{ start => $^T, args => 0 + @ARGV };
...might print something like:
This process was started at 2010-10-17 14:05:29 with 0 arguments.
DESCRIPTION
String::Errf provides "errf", a simple string formatter that works something like
"sprintf". It is implemented using String::Formatter and Sub::Exporter. Their
documentation may be useful in understanding or extending String::Errf. The "errf"
subroutine is only available when imported. Calling String::Errf::errf will not do what
you want.
PERL VERSION
This library should run on perls released even a long time ago. It should work on any
version of perl released in the last five years.
Although it may work on older versions of perl, no guarantee is made that the minimum
required version will not be increased. The version may be increased for any reason, and
there is no promise that patches will be accepted to lower the minimum required perl.
DIFFERENCES FROM SPRINTF
The data passed to "errf" should be organized in a single hashref, not a list.
Formatting codes require named parameters, and the available codes are different. See
"FORMATTING CODES" below.
As with most String::Formatter formatters, "%" is not a format code. If you want a
literal "%", do not put anything between the two percent signs, just write "%%".
UNDEF HANDLING
By default, formatting codes tend to treat "undef" like Perl does: coercing it to an empty
string or zero. This was a bad initial decision and will probably change. A "on_undef"
handler can be provided when importing "errf" to setup a callback for how undefs should be
handled. These two possibilities seem useful:
# Very lax; undefs always turn into the same string:
use String::Errf errf => { on_undef => sub { '(undef)' } };
# Strict; undefs are never valid:
use String::Errf errf => { on_undef => sub {
Carp::croak("undef passed to $_[1]{literal}") } };
} };
FORMATTING CODES
"errf" formatting codes require a set of arguments between the "%" and the formatting code
letter. These arguments are placed in curly braces and separated by semicolons. The
first argument is the name of the data to look for in the format data. For example, this
is a valid use of "errf":
errf "The current time in %{tz}s is %{now;local}t.", {
tz => $ENV{TZ},
now => time,
};
The second argument, if present, may be a compact form for multiple named arguments. The
rest of the arguments will be named values in the form "name=value". The examples below
should help clarify how arguments are passed. When an argument appears in both a compact
and named form, the named form trumps the compact form.
The specific codes and their arguments are:
s for string
The "s" format code is for any string, and takes no arguments. It just includes the named
item from the input data.
errf "%{name}s", { name => 'John Smith' }; # returns "John Smith"
Remember, "errf" does not have any of the left- or right-padding formatting that "sprintf"
provides. It is not meant for building tables, only strings.
i for integer
The "i" format code is used for integers. It takes one optional argument, "prefix", which
defaults to the empty string. "prefix" may be given as the compact argument, standing
alone. "prefix" is used to prefix non-negative integers. It may only be a plus sign.
errf "%{x}i", { x => 10 }; # returns "10"
errf "%{x;+}i", { x => 10 }; # returns "+10"
errf "%{x;prefix=+}i", { x => 10 }; # returns "+10"
The rounding behavior for non-integer values is not currently specified.
f for float (or fractional)
The "f" format code is for numbers with sub-integer precision. It works just like "i",
but adds a "precision" argument which specifies how many decimal places of precision to
display. The compact argument may be just the prefix or the prefix followed by a period
followed by the precision.
errf "%{x}f", { x => 10.1234 }; # returns "10";
errf "%{x;+}f", { x => 10.1234 }; # returns "+10";
errf "%{x;.2}f", { x => 10.1234 }; # returns "10.12";
errf "%{x;+.2}f", { x => 10.1234 }; # returns "+10.12";
errf "%{x;precision=.2}f", { x => 10.1234 }; # returns "10.12";
errf "%{x;prefix=+;precision=.2}f", { x => 10.1234 }; # returns "+10.12";
t for time
The "t" format code is used to format timestamps provided in epoch seconds. It can be
given two arguments: "type" and "tz".
"type" can be either date, time, or datetime, and indicates what part of the timestamp
should be displayed. The default is datetime. "tz" requests that the timestamp be
displayed in either UTC or the local time zone. The default is local.
The compact form is just "type" alone.
# Assuming our local time zone is America/New_York...
errf "%{x}t", { x => 1280530906 }; # "2010-07-30 19:01:46"
errf "%{x;type=date}t", { x => 1280530906 }; # "2010-07-30"
errf "%{x;type=time}t", { x => 1280530906 }; # "19:01:46"
errf "%{x;type=datetime}t", { x => 1280530906 }; # "2010-07-30 19:01:46"
errf "%{x;tz=UTC}t", { x => 1280530906 }; # "2010-07-30 23:01:46 UTC"
errf "%{x;tz=UTC;type=date}t", { x => 1280530906 }; # "2010-07-30 UTC"
errf "%{x;tz=UTC;type=time}t", { x => 1280530906 }; # "23:01:46 UTC"
errf "%{x;tz=UTC;type=datetime}t", { x => 1280530906 }; # "2010-07-30 23:01:46 UTC"
n and N for numbered
The "n" and "N" format codes are for picking words based on number. It takes two of its
own arguments, "singular" and "plural", as well as "prefix" and "precision" which may be
used for formatting the number itself.
If the value being formatted is 1, the singular word is used. Otherwise, the plural form
is used.
errf "%{x;singular=dog;plural=dogs}n", { x => 0 }; # 0 dogs
errf "%{x;singular=dog;plural=dogs}n", { x => 1 }; # 1 dog
errf "%{x;singular=dog;plural=dogs}n", { x => 2 }; # 2 dogs
errf "%{x;singular=dog;plural=dogs}n", { x => 1.4 }; # 1.4 dogs
errf "%{x;singular=dog;plural=dogs;precision=1}n", { x => 1.4 }; # 1.4 dogs
errf "%{x;singular=dog;plural=dogs;precision=0}n", { x => 1.4 }; # 1 dog
If "N" is used instead of "n", the number will not be included, only the chosen word.
errf "%{x;singular=is;plural=are}N", { x => 0 }; # are
errf "%{x;singular=is;plural=are}N", { x => 1 }; # is
errf "%{x;singular=is;plural=are}N", { x => 2 }; # are
errf "%{x;singular=is;plural=are}N", { x => 1.4 }; # 1.4 are
errf "%{x;singular=is;plural=are;precision=1}N", { x => 1.4 }; # 1.4 are
errf "%{x;singular=is;plural=are;precision=0}N", { x => 1.4 }; # 1 is
The compact form may take any of the following forms:
word - equivalent to singular=word
word+suffix - equivalent to singular=word;plural=wordsuffix
word1/word2 - equivalent to singular=word;plural=word2
If no singular form is given, an exception is thrown. If no plural form is given, one
will be generated according to some basic rules of English noun orthography.
AUTHOR
Ricardo Signes <cpan@semiotic.systems>
CONTRIBUTORS
• Karen Etheridge <ether@cpan.org>
• Pedro Melo <melo@simplicidade.org>
• Ricardo Signes <rjbs@semiotic.systems>
COPYRIGHT AND LICENSE
This software is copyright (c) 2022 by Ricardo Signes.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.