Provided by: perl-doc_5.40.0-8_all 
NAME
perlmodlib - constructing new Perl modules and finding existing ones
THE PERL MODULE LIBRARY
Many modules are included in the Perl distribution. These are described below, and all
end in .pm. You may discover compiled library files (usually ending in .so) or small
pieces of modules to be autoloaded (ending in .al); these were automatically generated by
the installation process. You may also discover files in the library directory that end
in either .pl or .ph. These are old libraries supplied so that old programs that use them
still run. The .pl files will all eventually be converted into standard modules, and the
.ph files made by h2ph will probably end up as extension modules made by h2xs. (Some .ph
values may already be available through the POSIX, Errno, or Fcntl modules.) The pl2pm
file in the distribution may help in your conversion, but it's just a mechanical process
and therefore far from bulletproof.
Pragmatic Modules
They work somewhat like compiler directives (pragmata) in that they tend to affect the
compilation of your program, and thus will usually work well only when used within a
"use", or "no". Most of these are lexically scoped, so an inner BLOCK may countermand
them by saying:
no integer;
no strict 'refs';
no warnings;
which lasts until the end of that BLOCK.
Some pragmas are lexically scoped--typically those that affect the $^H hints variable.
Others affect the current package instead, like "use vars" and "use subs", which allow you
to predeclare a variables or subroutines within a particular file rather than just a
block. Such declarations are effective for the entire file for which they were declared.
You cannot rescind them with "no vars" or "no subs".
The following pragmas are defined (and have their own documentation).
attributes Get/set subroutine or variable attributes
autodie Replace functions with ones that succeed or die with lexical scope
autodie::exception
Exceptions from autodying functions.
autodie::exception::system
Exceptions from autodying system().
autodie::hints
Provide hints about user subroutines to autodie
autodie::skip
Skip a package when throwing autodie exceptions
autouse Postpone load of modules until a function is used
base Establish an ISA relationship with base classes at compile time
bigfloat Transparent big floating point number support for Perl
bigint Transparent big integer support for Perl
bignum Transparent big number support for Perl
bigrat Transparent big rational number support for Perl
blib Use MakeMaker's uninstalled version of a package
builtin Import built-in utility functions
bytes Expose the individual bytes of characters
charnames Access to Unicode character names and named character sequences; also define
character names
constant Declare constants
deprecate Perl pragma for deprecating the inclusion of a module in core
diagnostics Produce verbose warning diagnostics
encoding Allows you to write your script in non-ASCII and non-UTF-8
encoding::warnings
Warn on implicit encoding conversions
experimental
Experimental features made easy
feature Enable new features
fields Compile-time class fields
filetest Control the filetest permission operators
if "use" a Perl module if a condition holds
integer Use integer arithmetic instead of floating point
less Request less of something
lib Manipulate @INC at compile time
locale Use or avoid POSIX locales for built-in operations
mro Method Resolution Order
ok Alternative to Test::More::use_ok
open Set default PerlIO layers for input and output
ops Restrict unsafe operations when compiling
overload Package for overloading Perl operations
overloading Lexically control overloading
parent Establish an ISA relationship with base classes at compile time
re Alter regular expression behaviour
sigtrap Enable simple signal handling
sort Control sort() behaviour
stable Experimental features made easy, once we know they're stable
strict Restrict unsafe constructs
subs Predeclare subroutine names
threads Perl interpreter-based threads
threads::shared
Perl extension for sharing data structures between threads
utf8 Enable/disable UTF-8 (or UTF-EBCDIC) in source code
vars Predeclare global variable names
version Perl extension for Version Objects
vmsish Control VMS-specific language features
warnings Control optional warnings
warnings::register
Warnings import function
Standard Modules
Standard, bundled modules are all expected to behave in a well-defined manner with respect
to namespace pollution because they use the Exporter module. See their own documentation
for details.
It's possible that not all modules listed below are installed on your system. For example,
the GDBM_File module will not be installed if you don't have the gdbm library.
Amiga::ARexx
Perl extension for ARexx support
Amiga::Exec Perl extension for low level amiga support
AnyDBM_File Provide framework for multiple DBMs
App::Cpan Easily interact with CPAN from the command line
App::Prove Implements the "prove" command.
App::Prove::State
State storage for the "prove" command.
App::Prove::State::Result
Individual test suite results.
App::Prove::State::Result::Test
Individual test results.
Archive::Tar
Module for manipulations of tar archives
Archive::Tar::File
A subclass for in-memory extracted file from Archive::Tar
Attribute::Handlers
Simpler definition of attribute handlers
AutoLoader Load subroutines only on demand
AutoSplit Split a package for autoloading
B The Perl Compiler Backend
B::Concise Walk Perl syntax tree, printing concise info about ops
B::Deparse Perl compiler backend to produce perl code
B::Op_private
OP op_private flag definitions
B::Showlex Show lexical variables used in functions or files
B::Terse Walk Perl syntax tree, printing terse info about ops
B::Xref Generates cross reference reports for Perl programs
Benchmark Benchmark running times of Perl code
"IO::Socket::IP"
Family-neutral IP socket supporting both IPv4 and IPv6
"Socket" Networking constants and support functions
"Test2::Tools::Refcount"
Assert reference counts on objects
CORE Namespace for Perl's core routines
CPAN Query, download and build perl modules from CPAN sites
CPAN::API::HOWTO
A recipe book for programming with CPAN.pm
CPAN::Debug Internal debugging for CPAN.pm
CPAN::Distroprefs
Read and match distroprefs
CPAN::FirstTime
Utility for CPAN::Config file Initialization
CPAN::HandleConfig
Internal configuration handling for CPAN.pm
CPAN::Kwalify
Interface between CPAN.pm and Kwalify.pm
CPAN::Meta The distribution metadata for a CPAN dist
CPAN::Meta::Converter
Convert CPAN distribution metadata structures
CPAN::Meta::Feature
An optional feature provided by a CPAN distribution
CPAN::Meta::History
History of CPAN Meta Spec changes
CPAN::Meta::History::Meta_1_0
Version 1.0 metadata specification for META.yml
CPAN::Meta::History::Meta_1_1
Version 1.1 metadata specification for META.yml
CPAN::Meta::History::Meta_1_2
Version 1.2 metadata specification for META.yml
CPAN::Meta::History::Meta_1_3
Version 1.3 metadata specification for META.yml
CPAN::Meta::History::Meta_1_4
Version 1.4 metadata specification for META.yml
CPAN::Meta::Merge
Merging CPAN Meta fragments
CPAN::Meta::Prereqs
A set of distribution prerequisites by phase and type
CPAN::Meta::Requirements
A set of version requirements for a CPAN dist
CPAN::Meta::Requirements::Range
A set of version requirements for a CPAN dist
CPAN::Meta::Spec
Specification for CPAN distribution metadata
CPAN::Meta::Validator
Validate CPAN distribution metadata structures
CPAN::Meta::YAML
Read and write a subset of YAML for CPAN Meta files
CPAN::Nox Wrapper around CPAN.pm without using any XS module
CPAN::Plugin
Base class for CPAN shell extensions
CPAN::Plugin::Specfile
Proof of concept implementation of a trivial CPAN::Plugin
CPAN::Queue Internal queue support for CPAN.pm
CPAN::Tarzip
Internal handling of tar archives for CPAN.pm
CPAN::Version
Utility functions to compare CPAN versions
Carp Alternative warn and die for modules
Class::Struct
Declare struct-like datatypes as Perl classes
Compress::Raw::Bzip2
Low-Level Interface to bzip2 compression library
Compress::Raw::Zlib
Low-Level Interface to zlib or zlib-ng compression library
Compress::Zlib
Interface to zlib compression library
Config Access Perl configuration information
Config::Extensions
Hash lookup of which core extensions were built.
Config::Perl::V
Structured data retrieval of perl -V output
Cwd Get pathname of current working directory
DB Programmatic interface to the Perl debugging API
DBM_Filter Filter DBM keys/values
DBM_Filter::compress
Filter for DBM_Filter
DBM_Filter::encode
Filter for DBM_Filter
DBM_Filter::int32
Filter for DBM_Filter
DBM_Filter::null
Filter for DBM_Filter
DBM_Filter::utf8
Filter for DBM_Filter
DB_File Perl5 access to Berkeley DB version 1.x
Data::Dumper
Stringified perl data structures, suitable for both printing and "eval"
Devel::PPPort
Perl/Pollution/Portability
Devel::Peek A data debugging tool for the XS programmer
Devel::SelfStubber
Generate stubs for a SelfLoading module
Digest Modules that calculate message digests
Digest::MD5 Perl interface to the MD5 Algorithm
Digest::SHA Perl extension for SHA-1/224/256/384/512
Digest::base
Digest base class
Digest::file
Calculate digests of files
DirHandle (obsolete) supply object methods for directory handles
Dumpvalue Provides screen dump of Perl data.
DynaLoader Dynamically load C libraries into Perl code
Encode Character encodings in Perl
Encode::Alias
Alias definitions to encodings
Encode::Byte
Single Byte Encodings
Encode::CJKConstants
Internally used by Encode::??::ISO_2022_*
Encode::CN China-based Chinese Encodings
Encode::CN::HZ
Internally used by Encode::CN
Encode::Config
Internally used by Encode
Encode::EBCDIC
EBCDIC Encodings
Encode::Encoder
Object Oriented Encoder
Encode::Encoding
Encode Implementation Base Class
Encode::GSM0338
ETSI GSM 03.38 Encoding
Encode::Guess
Guesses encoding from data
Encode::JP Japanese Encodings
Encode::JP::H2Z
Internally used by Encode::JP::2022_JP*
Encode::JP::JIS7
Internally used by Encode::JP
Encode::KR Korean Encodings
Encode::KR::2022_KR
Internally used by Encode::KR
Encode::MIME::Header
MIME encoding for an unstructured email header
Encode::MIME::Name
Internally used by Encode
Encode::PerlIO
A detailed document on Encode and PerlIO
Encode::Supported
Encodings supported by Encode
Encode::Symbol
Symbol Encodings
Encode::TW Taiwan-based Chinese Encodings
Encode::Unicode
Various Unicode Transformation Formats
Encode::Unicode::UTF7
UTF-7 encoding
English Use nice English (or awk) names for ugly punctuation variables
Env Perl module that imports environment variables as scalars or arrays
Errno System errno constants
Exporter Implements default import method for modules
Exporter::Heavy
Exporter guts
ExtUtils::CBuilder
Compile and link C code for Perl modules
ExtUtils::CBuilder::Platform::Windows
Builder class for Windows platforms
ExtUtils::Command
Utilities to replace common UNIX commands in Makefiles etc.
ExtUtils::Command::MM
Commands for the MM's to use in Makefiles
ExtUtils::Constant
Generate XS code to import C header constants
ExtUtils::Constant::Base
Base class for ExtUtils::Constant objects
ExtUtils::Constant::Utils
Helper functions for ExtUtils::Constant
ExtUtils::Constant::XS
Generate C code for XS modules' constants.
ExtUtils::Embed
Utilities for embedding Perl in C/C++ applications
ExtUtils::Install
Install files from here to there
ExtUtils::Installed
Inventory management of installed modules
ExtUtils::Liblist
Determine libraries to use and how to use them
ExtUtils::MM
OS adjusted ExtUtils::MakeMaker subclass
ExtUtils::MM_AIX
AIX specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_Any
Platform-agnostic MM methods
ExtUtils::MM_BeOS
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_Cygwin
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_DOS
DOS specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_Darwin
Special behaviors for OS X
ExtUtils::MM_MacOS
Once produced Makefiles for MacOS Classic
ExtUtils::MM_NW5
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_OS2
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_OS390
OS390 specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_QNX
QNX specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_UWIN
U/WIN specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_Unix
Methods used by ExtUtils::MakeMaker
ExtUtils::MM_VMS
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_VOS
VOS specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_Win32
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_Win95
Method to customize MakeMaker for Win9X
ExtUtils::MY
ExtUtils::MakeMaker subclass for customization
ExtUtils::MakeMaker
Create a module Makefile
ExtUtils::MakeMaker::Config
Wrapper around Config.pm
ExtUtils::MakeMaker::FAQ
Frequently Asked Questions About MakeMaker
ExtUtils::MakeMaker::Locale
Bundled Encode::Locale
ExtUtils::MakeMaker::Tutorial
Writing a module with MakeMaker
ExtUtils::Manifest
Utilities to write and check a MANIFEST file
ExtUtils::Miniperl
Write the C code for miniperlmain.c and perlmain.c
ExtUtils::Mkbootstrap
Make a bootstrap file for use by DynaLoader
ExtUtils::Mksymlists
Write linker options files for dynamic extension
ExtUtils::PL2Bat
Batch file creation to run perl scripts on Windows
ExtUtils::Packlist
Manage .packlist files
ExtUtils::ParseXS
Converts Perl XS code into C code
ExtUtils::ParseXS::Constants
Initialization values for some globals
ExtUtils::ParseXS::Eval
Clean package to evaluate code in
ExtUtils::ParseXS::Utilities
Subroutines used with ExtUtils::ParseXS
ExtUtils::Typemaps
Read/Write/Modify Perl/XS typemap files
ExtUtils::Typemaps::Cmd
Quick commands for handling typemaps
ExtUtils::Typemaps::InputMap
Entry in the INPUT section of a typemap
ExtUtils::Typemaps::OutputMap
Entry in the OUTPUT section of a typemap
ExtUtils::Typemaps::Type
Entry in the TYPEMAP section of a typemap
ExtUtils::XSSymSet
Keep sets of symbol names palatable to the VMS linker
ExtUtils::testlib
Add blib/* directories to @INC
Fatal Replace functions with equivalents which succeed or die
Fcntl Various flag constants and helper functions from C's fcntl.h
File::Basename
Parse file paths into directory, filename and suffix.
File::Compare
Compare files or filehandles
File::Copy Copy files or filehandles
File::DosGlob
DOS like globbing and then some
File::Fetch A generic file fetching mechanism
File::Find Traverse a directory tree.
File::Glob Perl extension for BSD glob routine
File::GlobMapper
Extend File Glob to Allow Input and Output Files
File::Path Create or remove directory trees
File::Spec Portably perform operations on file names
File::Spec::AmigaOS
File::Spec for AmigaOS
File::Spec::Cygwin
Methods for Cygwin file specs
File::Spec::Epoc
Methods for Epoc file specs
File::Spec::Functions
Portably perform operations on file names
File::Spec::Mac
File::Spec for Mac OS (Classic)
File::Spec::OS2
Methods for OS/2 file specs
File::Spec::Unix
File::Spec for Unix, base for other File::Spec modules
File::Spec::VMS
Methods for VMS file specs
File::Spec::Win32
Methods for Win32 file specs
File::Temp Return name and handle of a temporary file safely
File::stat By-name interface to Perl's built-in stat() functions
FileCache Keep more files open than the system permits
FileHandle Supply object methods for filehandles
Filter::Simple
Simplified source filtering
Filter::Util::Call
Perl Source Filter Utility Module
FindBin Locate directory of original Perl script
GDBM_File Perl5 access to the gdbm library.
Getopt::Long
Extended processing of command line options
Getopt::Long::Parser
Getopt::Long object oriented interface
Getopt::Std Process single-character switches with switch clustering
HTTP::Tiny A small, simple, correct HTTP/1.1 client
Hash::Util A selection of general-utility hash subroutines
Hash::Util::FieldHash
Support for Inside-Out Classes
I18N::Collate
Compare 8-bit scalar data according to the current locale
I18N::LangTags
Functions for dealing with RFC3066-style language tags
I18N::LangTags::Detect
Detect the user's language preferences
I18N::LangTags::List
Tags and names for human languages
I18N::Langinfo
Query locale information
IO Load various IO modules
IO::Compress::Base
Base Class for IO::Compress modules
IO::Compress::Bzip2
Write bzip2 files/buffers
IO::Compress::Deflate
Write RFC 1950 files/buffers
IO::Compress::FAQ
Frequently Asked Questions about IO::Compress
IO::Compress::Gzip
Write RFC 1952 files/buffers
IO::Compress::RawDeflate
Write RFC 1951 files/buffers
IO::Compress::Zip
Write zip files/buffers
IO::Dir Supply object methods for directory handles
IO::File Supply object methods for filehandles
IO::Handle Supply object methods for I/O handles
IO::Pipe Supply object methods for pipes
IO::Poll Object interface to system poll call
IO::Seekable
Supply seek based methods for I/O objects
IO::Select OO interface to the "select" system call
IO::Socket Object interface to socket communications
IO::Socket::INET
Object interface for AF_INET domain sockets
IO::Socket::UNIX
Object interface for AF_UNIX domain sockets
IO::Uncompress::AnyInflate
Uncompress zlib-based (zip, gzip) file/buffer
IO::Uncompress::AnyUncompress
Uncompress gzip, zip, bzip2, zstd, xz, lzma, lzip, lzf or lzop file/buffer
IO::Uncompress::Base
Base Class for IO::Uncompress modules
IO::Uncompress::Bunzip2
Read bzip2 files/buffers
IO::Uncompress::Gunzip
Read RFC 1952 files/buffers
IO::Uncompress::Inflate
Read RFC 1950 files/buffers
IO::Uncompress::RawInflate
Read RFC 1951 files/buffers
IO::Uncompress::Unzip
Read zip files/buffers
IO::Zlib IO:: style interface to Compress::Zlib
IPC::Cmd Finding and running system commands made easy
IPC::Msg SysV Msg IPC object class
IPC::Open2 Open a process for both reading and writing using open2()
IPC::Open3 Open a process for reading, writing, and error handling using open3()
IPC::Semaphore
SysV Semaphore IPC object class
IPC::SharedMem
SysV Shared Memory IPC object class
IPC::SysV System V IPC constants and system calls
Internals Reserved special namespace for internals related functions
JSON::PP JSON::XS compatible pure-Perl module.
JSON::PP::Boolean
Dummy module providing JSON::PP::Boolean
List::Util A selection of general-utility list subroutines
List::Util::XS
Indicate if List::Util was compiled with a C compiler
Locale::Maketext
Framework for localization
Locale::Maketext::Cookbook
Recipes for using Locale::Maketext
Locale::Maketext::Guts
Deprecated module to load Locale::Maketext utf8 code
Locale::Maketext::GutsLoader
Deprecated module to load Locale::Maketext utf8 code
Locale::Maketext::Simple
Simple interface to Locale::Maketext::Lexicon
Locale::Maketext::TPJ13
Article about software localization
MIME::Base64
Encoding and decoding of base64 strings
MIME::QuotedPrint
Encoding and decoding of quoted-printable strings
Math::BigFloat
Arbitrary size floating point math package
Math::BigInt
Arbitrary size integer math package
Math::BigInt::Calc
Pure Perl module to support Math::BigInt
Math::BigInt::FastCalc
Math::BigInt::Calc with some XS for more speed
Math::BigInt::Lib
Virtual parent class for Math::BigInt libraries
Math::BigRat
Arbitrary size rational number math package
Math::Complex
Complex numbers and associated mathematical functions
Math::Trig Trigonometric functions
Memoize Make functions faster by trading space for time
Memoize::AnyDBM_File
Glue to provide EXISTS for AnyDBM_File for Storable use
Memoize::Expire
Plug-in module for automatic expiration of memoized values
Memoize::NDBM_File
Glue to provide EXISTS for NDBM_File for Storable use
Memoize::SDBM_File
DEPRECATED compability shim
Memoize::Storable
Store Memoized data in Storable database
Module::CoreList
What modules shipped with versions of perl
Module::CoreList::Utils
What utilities shipped with versions of perl
Module::Load
Runtime require of both modules and files
Module::Load::Conditional
Looking up module information / loading at runtime
Module::Loaded
Mark modules as loaded or unloaded
Module::Metadata
Gather package and POD information from perl module files
NDBM_File Tied access to ndbm files
NEXT Provide a pseudo-class NEXT (et al) that allows method redispatch
Net::Cmd Network Command class (as used by FTP, SMTP etc)
Net::Config Local configuration data for libnet
Net::Domain Attempt to evaluate the current host's internet name and domain
Net::FTP FTP Client class
Net::FTP::dataconn
FTP Client data connection class
Net::NNTP NNTP Client class
Net::Netrc OO interface to users netrc file
Net::POP3 Post Office Protocol 3 Client class (RFC1939)
Net::Ping Check a remote host for reachability
Net::SMTP Simple Mail Transfer Protocol Client
Net::Time Time and daytime network client interface
Net::hostent
By-name interface to Perl's built-in gethost*() functions
Net::libnetFAQ
Libnet Frequently Asked Questions
Net::netent By-name interface to Perl's built-in getnet*() functions
Net::protoent
By-name interface to Perl's built-in getproto*() functions
Net::servent
By-name interface to Perl's built-in getserv*() functions
O Generic interface to Perl Compiler backends
ODBM_File Tied access to odbm files
Opcode Disable named opcodes when compiling perl code
POSIX Perl interface to IEEE Std 1003.1
Params::Check
A generic input parsing/checking mechanism.
Parse::CPAN::Meta
Parse META.yml and META.json CPAN metadata files
Perl::OSType
Map Perl operating system names to generic types
PerlIO On demand loader for PerlIO layers and root of PerlIO::* name space
PerlIO::encoding
Encoding layer
PerlIO::mmap
Memory mapped IO
PerlIO::scalar
In-memory IO, scalar IO
PerlIO::via Helper class for PerlIO layers implemented in perl
PerlIO::via::QuotedPrint
PerlIO layer for quoted-printable strings
Pod::Checker
Check pod documents for syntax errors
Pod::Escapes
For resolving Pod E<...> sequences
Pod::Functions
Group Perl's functions a la perlfunc.pod
Pod::Html Module to convert pod files to HTML
Pod::Html::Util
Helper functions for Pod-Html
Pod::Man Convert POD data to formatted *roff input
Pod::ParseLink
Parse an L<> formatting code in POD text
Pod::Perldoc
Look up Perl documentation in Pod format.
Pod::Perldoc::BaseTo
Base for Pod::Perldoc formatters
Pod::Perldoc::GetOptsOO
Customized option parser for Pod::Perldoc
Pod::Perldoc::ToANSI
Render Pod with ANSI color escapes
Pod::Perldoc::ToChecker
Let Perldoc check Pod for errors
Pod::Perldoc::ToMan
Let Perldoc render Pod as man pages
Pod::Perldoc::ToNroff
Let Perldoc convert Pod to nroff
Pod::Perldoc::ToPod
Let Perldoc render Pod as ... Pod!
Pod::Perldoc::ToRtf
Let Perldoc render Pod as RTF
Pod::Perldoc::ToTerm
Render Pod with terminal escapes
Pod::Perldoc::ToText
Let Perldoc render Pod as plaintext
Pod::Perldoc::ToTk
Let Perldoc use Tk::Pod to render Pod
Pod::Perldoc::ToXml
Let Perldoc render Pod as XML
Pod::Simple Framework for parsing Pod
Pod::Simple::Checker
Check the Pod syntax of a document
Pod::Simple::Debug
Put Pod::Simple into trace/debug mode
Pod::Simple::DumpAsText
Dump Pod-parsing events as text
Pod::Simple::DumpAsXML
Turn Pod into XML
Pod::Simple::HTML
Convert Pod to HTML
Pod::Simple::HTMLBatch
Convert several Pod files to several HTML files
Pod::Simple::JustPod
Just the Pod, the whole Pod, and nothing but the Pod
Pod::Simple::LinkSection
Represent "section" attributes of L codes
Pod::Simple::Methody
Turn Pod::Simple events into method calls
Pod::Simple::PullParser
A pull-parser interface to parsing Pod
Pod::Simple::PullParserEndToken
End-tokens from Pod::Simple::PullParser
Pod::Simple::PullParserStartToken
Start-tokens from Pod::Simple::PullParser
Pod::Simple::PullParserTextToken
Text-tokens from Pod::Simple::PullParser
Pod::Simple::PullParserToken
Tokens from Pod::Simple::PullParser
Pod::Simple::RTF
Format Pod as RTF
Pod::Simple::Search
Find POD documents in directory trees
Pod::Simple::SimpleTree
Parse Pod into a simple parse tree
Pod::Simple::Subclassing
Write a formatter as a Pod::Simple subclass
Pod::Simple::Text
Format Pod as plaintext
Pod::Simple::TextContent
Get the text content of Pod
Pod::Simple::XHTML
Format Pod as validating XHTML
Pod::Simple::XMLOutStream
Turn Pod into XML
Pod::Text Convert POD data to formatted text
Pod::Text::Color
Convert POD data to formatted color ASCII text
Pod::Text::Overstrike
Convert POD data to formatted overstrike text
Pod::Text::Termcap
Convert POD data to ASCII text with format escapes
Pod::Usage Extracts POD documentation and shows usage information
SDBM_File Tied access to sdbm files
Safe Compile and execute code in restricted compartments
Scalar::Util
A selection of general-utility scalar subroutines
Search::Dict
Look - search for key in dictionary file
SelectSaver Save and restore selected file handle
SelfLoader Load functions only on demand
Storable Persistence for Perl data structures
Sub::Util A selection of utility subroutines for subs and CODE references
Symbol Manipulate Perl symbols and their names
Sys::Hostname
Try every conceivable way to get hostname
Sys::Syslog Perl interface to the UNIX syslog(3) calls
Sys::Syslog::Win32
Win32 support for Sys::Syslog
TAP::Base Base class that provides common functionality to TAP::Parser
TAP::Formatter::Base
Base class for harness output delegates
TAP::Formatter::Color
Run Perl test scripts with color
TAP::Formatter::Console
Harness output delegate for default console output
TAP::Formatter::Console::ParallelSession
Harness output delegate for parallel console output
TAP::Formatter::Console::Session
Harness output delegate for default console output
TAP::Formatter::File
Harness output delegate for file output
TAP::Formatter::File::Session
Harness output delegate for file output
TAP::Formatter::Session
Abstract base class for harness output delegate
TAP::Harness
Run test scripts with statistics
TAP::Harness::Env
Parsing harness related environmental variables where appropriate
TAP::Object Base class that provides common functionality to all "TAP::*" modules
TAP::Parser Parse TAP output
TAP::Parser::Aggregator
Aggregate TAP::Parser results
TAP::Parser::Grammar
A grammar for the Test Anything Protocol.
TAP::Parser::Iterator
Base class for TAP source iterators
TAP::Parser::Iterator::Array
Iterator for array-based TAP sources
TAP::Parser::Iterator::Process
Iterator for process-based TAP sources
TAP::Parser::Iterator::Stream
Iterator for filehandle-based TAP sources
TAP::Parser::IteratorFactory
Figures out which SourceHandler objects to use for a given Source
TAP::Parser::Multiplexer
Multiplex multiple TAP::Parsers
TAP::Parser::Result
Base class for TAP::Parser output objects
TAP::Parser::Result::Bailout
Bailout result token.
TAP::Parser::Result::Comment
Comment result token.
TAP::Parser::Result::Plan
Plan result token.
TAP::Parser::Result::Pragma
TAP pragma token.
TAP::Parser::Result::Test
Test result token.
TAP::Parser::Result::Unknown
Unknown result token.
TAP::Parser::Result::Version
TAP syntax version token.
TAP::Parser::Result::YAML
YAML result token.
TAP::Parser::ResultFactory
Factory for creating TAP::Parser output objects
TAP::Parser::Scheduler
Schedule tests during parallel testing
TAP::Parser::Scheduler::Job
A single testing job.
TAP::Parser::Scheduler::Spinner
A no-op job.
TAP::Parser::Source
A TAP source & meta data about it
TAP::Parser::SourceHandler
Base class for different TAP source handlers
TAP::Parser::SourceHandler::Executable
Stream output from an executable TAP source
TAP::Parser::SourceHandler::File
Stream TAP from a text file.
TAP::Parser::SourceHandler::Handle
Stream TAP from an IO::Handle or a GLOB.
TAP::Parser::SourceHandler::Perl
Stream TAP from a Perl executable
TAP::Parser::SourceHandler::RawTAP
Stream output from raw TAP in a scalar/array ref.
TAP::Parser::YAMLish::Reader
Read YAMLish data from iterator
TAP::Parser::YAMLish::Writer
Write YAMLish data
Term::ANSIColor
Color screen output using ANSI escape sequences
Term::Cap Perl termcap interface
Term::Complete
Perl word completion module
Term::ReadLine
Perl interface to various "readline" packages.
Term::Table Format a header and rows into a table
Term::Table::Cell
Representation of a cell in a table.
Term::Table::CellStack
Combine several cells into one (vertical)
Term::Table::HashBase
Build hash based classes.
Term::Table::LineBreak
Break up lines for use in tables.
Term::Table::Util
Utilities for Term::Table.
Test Provides a simple framework for writing test scripts
Test2 Framework for writing test tools that all work together.
Test2::API Primary interface for writing Test2 based testing tools.
Test2::API::Breakage
What breaks at what version
Test2::API::Context
Object to represent a testing context.
Test2::API::Instance
Object used by Test2::API under the hood
Test2::API::InterceptResult
Representation of a list of events.
Test2::API::InterceptResult::Event
Representation of an event for use in
Test2::API::InterceptResult::Hub
Hub used by InterceptResult.
Test2::API::InterceptResult::Squasher
Encapsulation of the algorithm that
Test2::API::Stack
Object to manage a stack of Test2::Hub
Test2::AsyncSubtest
Object representing an async subtest.
Test2::AsyncSubtest::Event::Attach
Event to attach a subtest to the parent.
Test2::AsyncSubtest::Event::Detach
Event to detach a subtest from the parent.
Test2::AsyncSubtest::Hub
Hub used by async subtests.
Test2::Bundle
Documentation for bundles.
Test2::Bundle::Extended
Old name for Test2::V0
Test2::Bundle::More
ALMOST a drop-in replacement for Test::More.
Test2::Bundle::Simple
ALMOST a drop-in replacement for Test::Simple.
Test2::Compare
Test2 extension for writing deep comparison tools.
Test2::Compare::Array
Internal representation of an array comparison.
Test2::Compare::Bag
Internal representation of a bag comparison.
Test2::Compare::Base
Base class for comparison classes.
Test2::Compare::Bool
Compare two values as booleans
Test2::Compare::Custom
Custom field check for comparisons.
Test2::Compare::DeepRef
Ref comparison
Test2::Compare::Delta
Representation of differences between nested data
Test2::Compare::Event
Event specific Object subclass.
Test2::Compare::EventMeta
Meta class for events in deep comparisons
Test2::Compare::Float
Compare two values as numbers with tolerance.
Test2::Compare::Hash
Representation of a hash in a deep comparison.
Test2::Compare::Isa
Check if the value is an instance of the class.
Test2::Compare::Meta
Check library for meta-checks
Test2::Compare::Negatable
Poor mans 'role' for compare objects that can be negated.
Test2::Compare::Number
Compare two values as numbers
Test2::Compare::Object
Representation of an object during deep
Test2::Compare::OrderedSubset
Internal representation of an ordered subset.
Test2::Compare::Pattern
Use a pattern to validate values in a deep
Test2::Compare::Ref
Ref comparison
Test2::Compare::Regex
Regex direct comparison
Test2::Compare::Scalar
Representation of a Scalar Ref in deep
Test2::Compare::Set
Allows a field to be matched against a set of
Test2::Compare::String
Compare two values as strings
Test2::Compare::Undef
Check that something is undefined
Test2::Compare::Wildcard
Placeholder check.
Test2::Event
Base class for events
Test2::Event::Bail
Bailout!
Test2::Event::Diag
Diag event type
Test2::Event::Encoding
Set the encoding for the output stream
Test2::Event::Exception
Exception event
Test2::Event::Fail
Event for a simple failed assertion
Test2::Event::Generic
Generic event type.
Test2::Event::Note
Note event type
Test2::Event::Ok
Ok event type
Test2::Event::Pass
Event for a simple passing assertion
Test2::Event::Plan
The event of a plan
Test2::Event::Skip
Skip event type
Test2::Event::Subtest
Event for subtest types
Test2::Event::TAP::Version
Event for TAP version.
Test2::Event::V2
Second generation event.
Test2::Event::Waiting
Tell all procs/threads it is time to be done
Test2::EventFacet
Base class for all event facets.
Test2::EventFacet::About
Facet with event details.
Test2::EventFacet::Amnesty
Facet for assertion amnesty.
Test2::EventFacet::Assert
Facet representing an assertion.
Test2::EventFacet::Control
Facet for hub actions and behaviors.
Test2::EventFacet::Error
Facet for errors that need to be shown.
Test2::EventFacet::Hub
Facet for the hubs an event passes through.
Test2::EventFacet::Info
Facet for information a developer might care about.
Test2::EventFacet::Info::Table
Intermediary representation of a table.
Test2::EventFacet::Meta
Facet for meta-data
Test2::EventFacet::Parent
Facet for events contains other events
Test2::EventFacet::Plan
Facet for setting the plan
Test2::EventFacet::Render
Facet that dictates how to render an event.
Test2::EventFacet::Trace
Debug information for events
Test2::Formatter
Namespace for formatters.
Test2::Formatter::TAP
Standard TAP formatter
Test2::Hub The conduit through which all events flow.
Test2::Hub::Interceptor
Hub used by interceptor to grab results.
Test2::Hub::Interceptor::Terminator
Exception class used by
Test2::Hub::Subtest
Hub used by subtests
Test2::IPC Turn on IPC for threading or forking support.
Test2::IPC::Driver
Base class for Test2 IPC drivers.
Test2::IPC::Driver::Files
Temp dir + Files concurrency model.
Test2::Manual
Documentation hub for Test2 and Test2-Suite.
Test2::Manual::Anatomy
The hub for documentation of the inner workings of
Test2::Manual::Anatomy::API
Internals documentation for the API.
Test2::Manual::Anatomy::Context
Internals documentation for the Context
Test2::Manual::Anatomy::Event
The internals of events
Test2::Manual::Anatomy::Hubs
Internals documentation for the hub stack, and
Test2::Manual::Anatomy::IPC
Manual for the IPC system.
Test2::Manual::Anatomy::Utilities
Overview of utilities for Test2.
Test2::Manual::Concurrency
Documentation for Concurrency support.
Test2::Manual::Contributing
How to contribute to the Test2 project.
Test2::Manual::EndToEnd
Overview of Test2 from load to finish.
Test2::Manual::Testing
Hub for documentation about writing tests with Test2.
Test2::Manual::Testing::Introduction
Introduction to testing with Test2.
Test2::Manual::Testing::Migrating
How to migrate existing tests from
Test2::Manual::Testing::Planning
The many ways to set a plan.
Test2::Manual::Testing::Todo
Tutorial for marking tests as TODO.
Test2::Manual::Tooling
Manual page for tool authors.
Test2::Manual::Tooling::FirstTool
Write your first tool with Test2.
Test2::Manual::Tooling::Formatter
How to write a custom formatter, in our
Test2::Manual::Tooling::Nesting
Tutorial for using other tools within your
Test2::Manual::Tooling::Plugin::TestExit
How to safely add pre-exit
Test2::Manual::Tooling::Plugin::TestingDone
Run code when the test file is
Test2::Manual::Tooling::Plugin::ToolCompletes
How to add behaviors that occur
Test2::Manual::Tooling::Plugin::ToolStarts
How to add behaviors that occur
Test2::Manual::Tooling::Subtest
How to implement a tool that makes use of
Test2::Manual::Tooling::TestBuilder
This section maps Test::Builder methods
Test2::Manual::Tooling::Testing
Tutorial on how to test your testing tools.
Test2::Mock Module for managing mocked classes and instances.
Test2::Plugin
Documentation for plugins
Test2::Plugin::BailOnFail
Automatically bail out of testing on the first test
Test2::Plugin::DieOnFail
Automatically die on the first test failure.
Test2::Plugin::ExitSummary
Add extra diagnostics on failure at the end of the
Test2::Plugin::SRand
Control the random seed for more controlled test
Test2::Plugin::Times
Output timing data at the end of the test.
Test2::Plugin::UTF8
Test2 plugin to test with utf8.
Test2::Require
Base class and documentation for skip-unless type test
Test2::Require::AuthorTesting
Only run a test when the AUTHOR_TESTING
Test2::Require::AutomatedTesting
Only run a test when the AUTOMATED_TESTING
Test2::Require::EnvVar
Only run a test when a specific environment variable
Test2::Require::ExtendedTesting
Only run a test when the EXTENDED_TESTING
Test2::Require::Fork
Skip a test file unless the system supports forking
Test2::Require::Module
Skip tests if certain packages are not installed, or
Test2::Require::NonInteractiveTesting
Only run a test when the NONINTERACTIVE_TESTING
Test2::Require::Perl
Skip the test unless the necessary version of Perl is
Test2::Require::RealFork
Skip a test file unless the system supports true
Test2::Require::ReleaseTesting
Only run a test when the RELEASE_TESTING
Test2::Require::Threads
Skip a test file unless the system supports threading
Test2::Suite
Distribution with a rich set of tools built upon the Test2
Test2::Todo TODO extension for Test2.
Test2::Tools
Documentation for Tools.
Test2::Tools::AsyncSubtest
Tools for writing async subtests.
Test2::Tools::Basic
Test2 implementation of the basic testing tools.
Test2::Tools::Class
Test2 implementation of the tools for testing classes.
Test2::Tools::ClassicCompare
Classic (Test::More style) comparison tools.
Test2::Tools::Compare
Tools for comparing deep data structures.
Test2::Tools::Defer
Write tests that get executed at a later time
Test2::Tools::Encoding
Tools for managing the encoding of Test2 based
Test2::Tools::Event
Tools for generating test events.
Test2::Tools::Exception
Test2 based tools for checking exceptions
Test2::Tools::Exports
Tools for validating exporters.
Test2::Tools::GenTemp
Tool for generating a populated temp directory.
Test2::Tools::Grab
Temporarily intercept all events without adding a scope
Test2::Tools::Mock
Class/Instance mocking for Test2.
Test2::Tools::Ref
Tools for validating references.
Test2::Tools::Spec
RSPEC implementation on top of Test2::Workflow
Test2::Tools::Subtest
Tools for writing subtests
Test2::Tools::Target
Alias the testing target package.
Test2::Tools::Tester
Tools to help you test other testing tools.
Test2::Tools::Tiny
Tiny set of tools for unfortunate souls who cannot use
Test2::Tools::Warnings
Tools to verify warnings.
Test2::Transition
Transition notes when upgrading to Test2
Test2::Util Tools used by Test2 and friends.
Test2::Util::ExternalMeta
Allow third party tools to safely attach meta-data
Test2::Util::Facets2Legacy
Convert facet data to the legacy event API.
Test2::Util::Grabber
Object used to temporarily intercept all events.
Test2::Util::Guard
Inline copy of Scope::Guard
Test2::Util::HashBase
Build hash based classes.
Test2::Util::Importer
Inline copy of Importer.
Test2::Util::Ref
Tools for inspecting or manipulating references.
Test2::Util::Stash
Utilities for manipulating stashes and globs.
Test2::Util::Sub
Tools for inspecting and manipulating subs.
Test2::Util::Table
Format a header and rows into a table
Test2::Util::Table::LineBreak
Break up lines for use in tables.
Test2::Util::Times
Format timing/benchmark information.
Test2::Util::Trace
Legacy wrapper fro Test2::EventFacet::Trace.
Test2::V0 0Th edition of the Test2 recommended bundle.
Test2::Workflow
A test workflow is a way of structuring tests using
Test2::Workflow::BlockBase
Base class for all workflow blocks.
Test2::Workflow::Build
Represents a build in progress.
Test2::Workflow::Runner
Runs the workflows.
Test2::Workflow::Task
Encapsulation of a Task
Test2::Workflow::Task::Action
Encapsulation of an action.
Test2::Workflow::Task::Group
Encapsulation of a group (describe).
Test::Builder
Backend for building test libraries
Test::Builder::Formatter
Test::Builder subclass of Test2::Formatter::TAP
Test::Builder::IO::Scalar
A copy of IO::Scalar for Test::Builder
Test::Builder::Module
Base class for test modules
Test::Builder::Tester
Test testsuites that have been built with
Test::Builder::Tester::Color
Turn on colour in Test::Builder::Tester
Test::Builder::TodoDiag
Test::Builder subclass of Test2::Event::Diag
Test::Harness
Run Perl standard test scripts with statistics
Test::Harness::Beyond
Beyond make test
Test::More Yet another framework for writing test scripts
Test::Simple
Basic utilities for writing tests.
Test::Tester
Ease testing test modules built with Test::Builder
Test::Tester::Capture
Help testing test modules built with Test::Builder
Test::Tester::CaptureRunner
Help testing test modules built with Test::Builder
Test::Tutorial
A tutorial about writing really basic tests
Test::use::ok
Alternative to Test::More::use_ok
Text::Abbrev
Abbrev - create an abbreviation table from a list
Text::Balanced
Extract delimited text sequences from strings.
Text::ParseWords
Parse text into an array of tokens or array of arrays
Text::Tabs Expand and unexpand tabs like unix expand(1) and unexpand(1)
Text::Wrap Line wrapping to form simple paragraphs
Thread Manipulate threads in Perl (for old code only)
Thread::Queue
Thread-safe queues
Thread::Semaphore
Thread-safe semaphores
Tie::Array Base class for tied arrays
Tie::File Access the lines of a disk file via a Perl array
Tie::Handle Base class definitions for tied handles
Tie::Hash Base class definitions for tied hashes
Tie::Hash::NamedCapture
Named regexp capture buffers
Tie::Memoize
Add data to hash when needed
Tie::RefHash
Use references as hash keys
Tie::Scalar Base class definitions for tied scalars
Tie::StdHandle
Base class definitions for tied handles
Tie::SubstrHash
Fixed-table-size, fixed-key-length hashing
Time::HiRes High resolution alarm, sleep, gettimeofday, interval timers
Time::Local Efficiently compute time from local and GMT time
Time::Piece Object Oriented time objects
Time::Seconds
A simple API to convert seconds to other date values
Time::gmtime
By-name interface to Perl's built-in gmtime() function
Time::localtime
By-name interface to Perl's built-in localtime() function
Time::tm Internal object used by Time::gmtime and Time::localtime
UNIVERSAL Base class for ALL classes (blessed references)
Unicode::Collate
Unicode Collation Algorithm
Unicode::Collate::CJK::Big5
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::GB2312
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::JISX0208
Weighting JIS KANJI for Unicode::Collate
Unicode::Collate::CJK::Korean
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::Pinyin
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::Stroke
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::Zhuyin
Weighting CJK Unified Ideographs
Unicode::Collate::Locale
Linguistic tailoring for DUCET via Unicode::Collate
Unicode::Normalize
Unicode Normalization Forms
Unicode::UCD
Unicode character database
User::grent By-name interface to Perl's built-in getgr*() functions
User::pwent By-name interface to Perl's built-in getpw*() functions
VMS::DCLsym Perl extension to manipulate DCL symbols
VMS::Filespec
Convert between VMS and Unix file specification syntax
VMS::Stdio Standard I/O functions via VMS extensions
Win32 Interfaces to some Win32 API Functions
Win32API::File
Low-level access to Win32 system API calls for files/dirs.
Win32CORE Win32 CORE function stubs
XS::APItest Test the perl C API
XS::Typemap Module to test the XS typemaps distributed with perl
XSLoader Dynamically load C libraries into Perl code
autodie::Scope::Guard
Wrapper class for calling subs at end of scope
autodie::Scope::GuardStack
Hook stack for managing scopes via %^H
autodie::Util
Internal Utility subroutines for autodie and Fatal
version::Internals
Perl extension for Version Objects
To find out all modules installed on your system, including those without documentation or
outside the standard release, just use the following command (under the default win32
shell, double quotes should be used instead of single quotes).
% perl -MFile::Find=find -MFile::Spec::Functions -Tlwe \
'find { wanted => sub { print canonpath $_ if /\.pm\z/ },
no_chdir => 1 }, @INC'
(The -T is here to prevent @INC from being populated by "PERL5LIB", "PERLLIB", and
"PERL_USE_UNSAFE_INC".) They should all have their own documentation installed and
accessible via your system man(1) command. If you do not have a find program, you can use
the Perl find2perl program instead, which generates Perl code as output you can run
through perl. If you have a man program but it doesn't find your modules, you'll have to
fix your manpath. See perl for details. If you have no system man command, you might try
the perldoc program.
Note also that the command "perldoc perllocal" gives you a (possibly incomplete) list of
the modules that have been further installed on your system. (The perllocal.pod file is
updated by the standard MakeMaker install process.)
Extension Modules
Extension modules are written in C (or a mix of Perl and C). They are usually dynamically
loaded into Perl if and when you need them, but may also be linked in statically.
Supported extension modules include Socket, Fcntl, and POSIX.
Many popular C extension modules do not come bundled (at least, not completely) due to
their sizes, volatility, or simply lack of time for adequate testing and configuration
across the multitude of platforms on which Perl was beta-tested. You are encouraged to
look for them on CPAN (described below), or using web search engines like Google or
DuckDuckGo.
CPAN
CPAN stands for Comprehensive Perl Archive Network; it's a globally replicated trove of
Perl materials, including documentation, style guides, tricks and traps, alternate ports
to non-Unix systems and occasional binary distributions for these. Search engines for
CPAN can be found at https://www.cpan.org/
Most importantly, CPAN includes around a thousand unbundled modules, some of which require
a C compiler to build. Major categories of modules are:
• Language Extensions and Documentation Tools
• Development Support
• Operating System Interfaces
• Networking, Device Control (modems) and InterProcess Communication
• Data Types and Data Type Utilities
• Database Interfaces
• User Interfaces
• Interfaces to / Emulations of Other Programming Languages
• File Names, File Systems and File Locking (see also File Handles)
• String Processing, Language Text Processing, Parsing, and Searching
• Option, Argument, Parameter, and Configuration File Processing
• Internationalization and Locale
• Authentication, Security, and Encryption
• World Wide Web, HTML, HTTP, CGI, MIME
• Server and Daemon Utilities
• Archiving and Compression
• Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing
• Mail and Usenet News
• Control Flow Utilities (callbacks and exceptions etc)
• File Handle and Input/Output Stream Utilities
• Miscellaneous Modules
You can find the CPAN online at <https://www.cpan.org/>
Modules: Creation, Use, and Abuse
(The following section is borrowed directly from Tim Bunce's modules file, available at
your nearest CPAN site.)
Perl implements a class using a package, but the presence of a package doesn't imply the
presence of a class. A package is just a namespace. A class is a package that provides
subroutines that can be used as methods. A method is just a subroutine that expects, as
its first argument, either the name of a package (for "static" methods), or a reference to
something (for "virtual" methods).
A module is a file that (by convention) provides a class of the same name (sans the .pm),
plus an import method in that class that can be called to fetch exported symbols. This
module may implement some of its methods by loading dynamic C or C++ objects, but that
should be totally transparent to the user of the module. Likewise, the module might set
up an AUTOLOAD function to slurp in subroutine definitions on demand, but this is also
transparent. Only the .pm file is required to exist. See perlsub, perlobj, and
AutoLoader for details about the AUTOLOAD mechanism.
Guidelines for Module Creation
• Do similar modules already exist in some form?
If so, please try to reuse the existing modules either in whole or by inheriting
useful features into a new class. If this is not practical try to get together with
the module authors to work on extending or enhancing the functionality of the existing
modules. A perfect example is the plethora of packages in perl4 for dealing with
command line options.
If you are writing a module to expand an already existing set of modules, please
coordinate with the author of the package. It helps if you follow the same naming
scheme and module interaction scheme as the original author.
• Try to design the new module to be easy to extend and reuse.
Try to "use warnings;" (or "use warnings qw(...);"). Remember that you can add "no
warnings qw(...);" to individual blocks of code that need less warnings.
Use blessed references. Use the two argument form of bless to bless into the class
name given as the first parameter of the constructor, e.g.,:
sub new {
my $class = shift;
return bless {}, $class;
}
or even this if you'd like it to be used as either a static or a virtual method.
sub new {
my $self = shift;
my $class = ref($self) || $self;
return bless {}, $class;
}
Pass arrays as references so more parameters can be added later (it's also faster).
Convert functions into methods where appropriate. Split large methods into smaller
more flexible ones. Inherit methods from other modules if appropriate.
Avoid class name tests like: "die "Invalid" unless ref $ref eq 'FOO'". Generally you
can delete the "eq 'FOO'" part with no harm at all. Let the objects look after
themselves! Generally, avoid hard-wired class names as far as possible.
Avoid "$r->Class::func()" where using "@ISA=qw(... Class ...)" and "$r->func()" would
work.
Use autosplit so little used or newly added functions won't be a burden to programs
that don't use them. Add test functions to the module after __END__ either using
AutoSplit or by saying:
eval join('',<main::DATA>) || die $@ unless caller();
Does your module pass the 'empty subclass' test? If you say "@SUBCLASS::ISA =
qw(YOURCLASS);" your applications should be able to use SUBCLASS in exactly the same
way as YOURCLASS. For example, does your application still work if you change: "$obj
= YOURCLASS->new();" into: "$obj = SUBCLASS->new();" ?
Avoid keeping any state information in your packages. It makes it difficult for
multiple other packages to use yours. Keep state information in objects.
Always use -w.
Try to "use strict;" (or "use strict qw(...);"). Remember that you can add "no strict
qw(...);" to individual blocks of code that need less strictness.
Always use -w.
Follow the guidelines in perlstyle.
Always use -w.
• Some simple style guidelines
The perlstyle manual supplied with Perl has many helpful points.
Coding style is a matter of personal taste. Many people evolve their style over
several years as they learn what helps them write and maintain good code. Here's one
set of assorted suggestions that seem to be widely used by experienced developers:
Use underscores to separate words. It is generally easier to read
$var_names_like_this than $VarNamesLikeThis, especially for non-native speakers of
English. It's also a simple rule that works consistently with VAR_NAMES_LIKE_THIS.
Package/Module names are an exception to this rule. Perl informally reserves lowercase
module names for 'pragma' modules like integer and strict. Other modules normally
begin with a capital letter and use mixed case with no underscores (need to be short
and portable).
You may find it helpful to use letter case to indicate the scope or nature of a
variable. For example:
$ALL_CAPS_HERE constants only (beware clashes with Perl vars)
$Some_Caps_Here package-wide global/static
$no_caps_here function scope my() or local() variables
Function and method names seem to work best as all lowercase. e.g.,
"$obj->as_string()".
You can use a leading underscore to indicate that a variable or function should not be
used outside the package that defined it.
• Select what to export.
Do NOT export method names!
Do NOT export anything else by default without a good reason!
Exports pollute the namespace of the module user. If you must export try to use
@EXPORT_OK in preference to @EXPORT and avoid short or common names to reduce the risk
of name clashes.
Generally anything not exported is still accessible from outside the module using the
ModuleName::item_name (or "$blessed_ref->method") syntax. By convention you can use a
leading underscore on names to indicate informally that they are 'internal' and not
for public use.
(It is actually possible to get private functions by saying: "my $subref = sub { ...
}; &$subref;". But there's no way to call that directly as a method, because a
method must have a name in the symbol table.)
As a general rule, if the module is trying to be object oriented then export nothing.
If it's just a collection of functions then @EXPORT_OK anything but use @EXPORT with
caution.
• Select a name for the module.
This name should be as descriptive, accurate, and complete as possible. Avoid any
risk of ambiguity. Always try to use two or more whole words. Generally the name
should reflect what is special about what the module does rather than how it does it.
Please use nested module names to group informally or categorize a module. There
should be a very good reason for a module not to have a nested name. Module names
should begin with a capital letter.
Having 57 modules all called Sort will not make life easy for anyone (though having 23
called Sort::Quick is only marginally better :-). Imagine someone trying to install
your module alongside many others.
If you are developing a suite of related modules/classes it's good practice to use
nested classes with a common prefix as this will avoid namespace clashes. For example:
Xyz::Control, Xyz::View, Xyz::Model etc. Use the modules in this list as a naming
guide.
If adding a new module to a set, follow the original author's standards for naming
modules and the interface to methods in those modules.
If developing modules for private internal or project specific use, that will never be
released to the public, then you should ensure that their names will not clash with
any future public module. You can do this either by using the reserved Local::*
category or by using a category name that includes an underscore like Foo_Corp::*.
To be portable each component of a module name should be limited to 11 characters. If
it might be used on MS-DOS then try to ensure each is unique in the first 8
characters. Nested modules make this easier.
For additional guidance on the naming of modules, please consult:
https://pause.perl.org/pause/query?ACTION=pause_namingmodules
or send mail to the <module-authors@perl.org> mailing list.
• Have you got it right?
How do you know that you've made the right decisions? Have you picked an interface
design that will cause problems later? Have you picked the most appropriate name? Do
you have any questions?
The best way to know for sure, and pick up many helpful suggestions, is to ask someone
who knows. The <module-authors@perl.org> mailing list is useful for this purpose; it's
also accessible via news interface as perl.module-authors at nntp.perl.org.
All you need to do is post a short summary of the module, its purpose and interfaces.
A few lines on each of the main methods is probably enough. (If you post the whole
module it might be ignored by busy people - generally the very people you want to read
it!)
Don't worry about posting if you can't say when the module will be ready - just say so
in the message. It might be worth inviting others to help you, they may be able to
complete it for you!
• README and other Additional Files.
It's well known that software developers usually fully document the software they
write. If, however, the world is in urgent need of your software and there is not
enough time to write the full documentation please at least provide a README file
containing:
• A description of the module/package/extension etc.
• A copyright notice - see below.
• Prerequisites - what else you may need to have.
• How to build it - possible changes to Makefile.PL etc.
• How to install it.
• Recent changes in this release, especially incompatibilities
• Changes / enhancements you plan to make in the future.
If the README file seems to be getting too large you may wish to split out some of the
sections into separate files: INSTALL, Copying, ToDo etc.
• Adding a Copyright Notice.
How you choose to license your work is a personal decision. The general mechanism
is to assert your Copyright and then make a declaration of how others may
copy/use/modify your work.
Perl, for example, is supplied with two types of licence: The GNU GPL and The
Artistic Licence (see the files README, Copying, and Artistic, or perlgpl and
perlartistic). Larry has good reasons for NOT just using the GNU GPL.
My personal recommendation, out of respect for Larry, Perl, and the Perl community
at large is to state something simply like:
Copyright (c) 1995 Your Name. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
This statement should at least appear in the README file. You may also wish to
include it in a Copying file and your source files. Remember to include the other
words in addition to the Copyright.
• Give the module a version/issue/release number.
To be fully compatible with the Exporter and MakeMaker modules you should store
your module's version number in a non-my package variable called $VERSION. This
should be a positive floating point number with at least two digits after the
decimal (i.e., hundredths, e.g, "$VERSION = "0.01""). Don't use a "1.3.2" style
version. See Exporter for details.
It may be handy to add a function or method to retrieve the number. Use the
number in announcements and archive file names when releasing the module
(ModuleName-1.02.tar.Z). See perldoc ExtUtils::MakeMaker.pm for details.
• How to release and distribute a module.
If possible, register the module with CPAN. Follow the instructions and links on:
https://www.cpan.org/modules/04pause.html
and upload to:
https://pause.perl.org/
and notify <modules@perl.org>. This will allow anyone to install your module using
the "cpan" tool distributed with Perl.
By using the WWW interface you can ask the Upload Server to mirror your modules
from your ftp or WWW site into your own directory on CPAN!
• Take care when changing a released module.
Always strive to remain compatible with previous released versions. Otherwise try
to add a mechanism to revert to the old behavior if people rely on it. Document
incompatible changes.
Guidelines for Converting Perl 4 Library Scripts into Modules
• There is no requirement to convert anything.
If it ain't broke, don't fix it! Perl 4 library scripts should continue to work with
no problems. You may need to make some minor changes (like escaping non-array @'s in
double quoted strings) but there is no need to convert a .pl file into a Module for
just that.
• Consider the implications.
All Perl applications that make use of the script will need to be changed (slightly)
if the script is converted into a module. Is it worth it unless you plan to make
other changes at the same time?
• Make the most of the opportunity.
If you are going to convert the script to a module you can use the opportunity to
redesign the interface. The guidelines for module creation above include many of the
issues you should consider.
• The pl2pm utility will get you started.
This utility will read *.pl files (given as parameters) and write corresponding *.pm
files. The pl2pm utilities does the following:
• Adds the standard Module prologue lines
• Converts package specifiers from ' to ::
• Converts die(...) to croak(...)
• Several other minor changes
Being a mechanical process pl2pm is not bullet proof. The converted code will need
careful checking, especially any package statements. Don't delete the original .pl
file till the new .pm one works!
Guidelines for Reusing Application Code
• Complete applications rarely belong in the Perl Module Library.
• Many applications contain some Perl code that could be reused.
Help save the world! Share your code in a form that makes it easy to reuse.
• Break-out the reusable code into one or more separate module files.
• Take the opportunity to reconsider and redesign the interfaces.
• In some cases the 'application' can then be reduced to a small
fragment of code built on top of the reusable modules. In these cases the application
could invoked as:
% perl -e 'use Module::Name; method(@ARGV)' ...
or
% perl -mModule::Name ... (in perl5.002 or higher)
NOTE
Perl does not enforce private and public parts of its modules as you may have been used to
in other languages like C++, Ada, or Modula-17. Perl doesn't have an infatuation with
enforced privacy. It would prefer that you stayed out of its living room because you
weren't invited, not because it has a shotgun.
The module and its user have a contract, part of which is common law, and part of which is
"written". Part of the common law contract is that a module doesn't pollute any namespace
it wasn't asked to. The written contract for the module (A.K.A. documentation) may make
other provisions. But then you know when you "use RedefineTheWorld" that you're
redefining the world and willing to take the consequences.