Manual - Section 1: perlmodlib

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

no subs

The following pragmas are defined (and have their own documentation).

attributes Get/set subroutine or variable attributes

attrs Set/get attributes of a subroutine (deprecated)

autouse Postpone load of modules until a function is used

base Establish an ISA relationship with base classes at compile time

bigint Transparent BigInteger support for Perl

bignum Transparent BigNumber support for Perl

bigrat Transparent BigNumber/BigRational support for Perl

blib Use MakeMaker’s uninstalled version of a package

bytes Force byte semantics rather than character semantics

charnames Define character names for
\N{named}
string literal escapes

constant Declare constants

diagnostics Produce verbose warning diagnostics

encoding Allows you to write your script in non-ascii or non-utf8

encoding::warnings Warn on implicit encoding conversions

feature Enable new syntactic 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 and avoid POSIX locales for built-in operations

mro Method Resolution Order

open Set default PerlIO layers for input and output

ops Restrict unsafe operations when compiling

overload Package for overloading Perl operations

re Alter regular expression behaviour

sigtrap Enable simple signal handling

sort Control sort() behaviour

strict Restrict unsafe constructs

subs Predeclare sub 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 (obsolete)

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.

AnyDBM_File Provide framework for multiple DBMs

Archive::Extract A generic archive extracting mechanism

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

B::Concise Walk Perl syntax tree, printing concise info about ops

B::Debug Walk Perl syntax tree, printing debug info about ops

B::Deparse Perl compiler backend to produce perl code

B::Lint Perl lint

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

CGI Simple Common Gateway Interface Class

CGI::Apache Backward compatibility module for CGI.pm

CGI::Carp CGI routines for writing to the HTTPD (or other) error log

CGI::Cookie Interface to Netscape Cookies

CGI::Fast CGI Interface for Fast CGI

CGI::Pretty Module to produce nicely formatted HTML code

CGI::Push Simple Interface to Server Push

CGI::Switch Backward compatibility module for defunct CGI::Switch

CGI::Util Internal utilities used by CGI module

CORE Pseudo-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::FirstTime Utility for CPAN::Config file Initialization

CPAN::Kwalify Interface between CPAN.pm and Kwalify.pm

CPAN::Nox Wrapper around CPAN.pm without using any XS module

CPAN::Version Utility functions to compare CPAN versions

CPANPLUS API & CLI access to the CPAN mirrors

CPANPLUS::Dist::Base Base class for custom distribution classes

CPANPLUS::Dist::Sample Sample code to create your own Dist::* plugin

CPANPLUS::Shell::Classic CPAN.pm emulation for CPANPLUS

CPANPLUS::Shell::Default::Plugins::HOWTO Documentation on how to write your own plugins

Carp Warn of errors (from perspective of caller)

Carp::Heavy Heavy machinery, no user serviceable parts inside

Class::ISA Report the search path for a class’s ISA tree

Class::Struct Declare struct-like datatypes as Perl classes

Compress::Raw::Zlib Low-Level Interface to zlib compression library

Compress::Zlib Interface to zlib compression library

Config Access Perl configuration information

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::DProf A Perl code profiler

Devel::InnerPackage Find all the inner packages of a package

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 Supply object methods for directory handles

Dumpvalue Provides screen dump of Perl data.

DynaLoader Dynamically load C libraries into Perl code

Encode Character encodings

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 ESTI 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 ’B’ and ’Q’ header encoding

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 Base class for ExtUtils::Constant objects

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_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_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::Tutorial Writing a module with MakeMaker

ExtUtils::MakeMaker::bytes Version-agnostic bytes.pm

ExtUtils::MakeMaker::vmsish Platform-agnostic vmsish.pm

ExtUtils::Manifest Utilities to write and check a MANIFEST file

ExtUtils::Mkbootstrap Make a bootstrap file for use by DynaLoader

ExtUtils::Mksymlists Write linker options files for dynamic extension

ExtUtils::Packlist Manage .packlist files

ExtUtils::ParseXS Converts Perl XS code into C code

ExtUtils::testlib Add blib/* directories to
@INC

Fatal Replace functions with equivalents which succeed or die

Fcntl Load the C Fcntl.h defines

File::Basename Parse file paths into directory, filename and suffix.

File::CheckTree Run many filetest checks on a tree

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::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::Std Process single-character switches with switch clustering

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::Deflate Write RFC 1950 files/buffers

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 or lzop file/buffer

IO::Uncompress::Base Base Class for IO::Uncompress modules

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::Open2 Open a process for both reading and writing

IPC::Open3 Open a process for reading, writing, and error handling

IPC::SysV SysV IPC constants

IPC::SysV::Msg SysV Msg IPC object class

IPC::SysV::Semaphore SysV Semaphore IPC object class

List::Util A selection of general-utility list subroutines

Locale::Constants Constants for Locale codes

Locale::Country ISO codes for country identification (ISO 3166)

Locale::Currency ISO three letter codes for currency identification (ISO 4217)

Locale::Language ISO two letter codes for language identification (ISO 639)

Locale::Maketext Framework for localization

Locale::Maketext::Simple Simple interface to Locale::Maketext::Lexicon

Locale::Maketext::TPJ13 Article about software localization

Locale::Script ISO codes for script identification (ISO 15924)

Log::Message A generic message storing mechanism;

Log::Message::Config Configuration options for Log::Message

Log::Message::Handlers Message handlers for Log::Message

Log::Message::Item Message objects for Log::Message

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/float math package

Math::BigInt::Calc Pure Perl module to support Math::BigInt

Math::BigInt::CalcEmu Emulate low-level math with BigInt code

Math::BigInt::FastCalc Math::BigInt::Calc with some XS for more speed

Math::BigRat Arbitrary big rational numbers

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::ExpireFile Test for Memoize expiration semantics

Memoize::ExpireTest Test for Memoize expiration semantics

Memoize::NDBM_File Glue to provide EXISTS for NDBM_File for Storable use

Memoize::SDBM_File Glue to provide EXISTS for SDBM_File for Storable use

Memoize::Storable Store Memoized data in Storable database

Module::Build Build and install Perl modules

Module::Build::API API Reference for Module Authors

Module::Build::Authoring Authoring Module::Build modules

Module::Build::Base Default methods for Module::Build

Module::Build::Compat Compatibility with ExtUtils::MakeMaker

Module::Build::ConfigData Configuration for Module::Build

Module::Build::Cookbook Examples of Module::Build Usage

Module::Build::ModuleInfo Gather package and POD information from a perl module files

Module::Build::Notes Configuration for
$module_name

Module::Build::PPMMaker Perl Package Manager file creation

Module::Build::Platform::Amiga Builder class for Amiga platforms

Module::Build::Platform::Default Stub class for unknown platforms

Module::Build::Platform::EBCDIC Builder class for EBCDIC platforms

Module::Build::Platform::MPEiX Builder class for MPEiX platforms

Module::Build::Platform::MacOS Builder class for MacOS platforms

Module::Build::Platform::RiscOS Builder class for RiscOS platforms

Module::Build::Platform::Unix Builder class for Unix platforms

Module::Build::Platform::VMS Builder class for VMS platforms

Module::Build::Platform::VOS Builder class for VOS platforms

Module::Build::Platform::Windows Builder class for Windows platforms

Module::Build::Platform::aix Builder class for AIX platform

Module::Build::Platform::cygwin Builder class for Cygwin platform

Module::Build::Platform::darwin Builder class for Mac OS X platform

Module::Build::Platform::os2 Builder class for OS/2 platform

Module::Build::YAML Provides just enough YAML support so that Module::Build works even if YAML.pm is not installed

Module::CoreList What modules 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::Pluggable Automatically give your module the ability to have plugins

Module::Pluggable::Object Automatically give your module the ability to have plugins

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::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

Package::Constants List all constants declared in a package

Params::Check A generic input parsing/checking mechanism.

PerlIO On demand loader for PerlIO layers and root of PerlIO::* name space

PerlIO::encoding Encoding layer

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::Find Find POD documents in directory trees

Pod::Functions Group Perl’s functions a la perlfunc.pod

Pod::Html Module to convert pod files to HTML

Pod::InputObjects Objects representing POD input paragraphs, commands, etc.

Pod::LaTeX Convert Pod data to formatted Latex

Pod::Man Convert POD data to formatted *roff input

Pod::ParseLink Parse an L<> formatting code in POD text

Pod::ParseUtils Helpers for POD parsing and conversion

Pod::Parser Base class for creating POD filters and translators

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::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::PlainText Convert POD data to formatted ASCII text

Pod::Plainer Perl extension for converting Pod to old style Pod.

Pod::Select Extract selected sections of POD from input

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::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::XMLOutStream Turn Pod into XML

Pod::Text Convert POD data to formatted ASCII 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 Print a usage message from embedded pod documentation

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 Search for key in dictionary file

SelectSaver Save and restore selected file handle

SelfLoader Load functions only on demand

Shell Run shell commands transparently within perl

Socket Load the C socket.h defines and structure manipulators

Storable Persistence for Perl data structures

Switch A switch statement for Perl

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 Win32 support for Sys::Syslog

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::UI Term::ReadLine UI made easy

Test Provides a simple framework for writing test scripts

Test::Builder Backend for building test libraries

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::Harness Run Perl standard test scripts with statistics

Test::Harness::Assert Simple assert

Test::Harness::Iterator Internal Test::Harness Iterator

Test::Harness::Point Object for tracking a single test point

Test::Harness::Results Object for tracking results from a single test file

Test::Harness::Straps Detailed analysis of test results

Test::Harness::TAP Documentation for the TAP format

Test::Harness::Util Utility functions for Test::Harness::*

Test::More Yet another framework for writing test scripts

Test::Simple Basic utilities for writing tests.

Test::Tutorial A tutorial about writing really basic tests

Text::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::Soundex Implementation of the soundex algorithm.

Text::Tabs Expand and unexpand tabs per the 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::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::Piece::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::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

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

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 ’.’ from being listed in

@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 Alta Vista or Google.

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 http://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:

o Language Extensions and Documentation Tools

o Development Support

o Operating System Interfaces

o Networking, Device Control (modems) and InterProcess Communication

o Data Types and Data Type Utilities

o Database Interfaces

o User Interfaces

o Interfaces to / Emulations of Other Programming Languages

o File Names, File Systems and File Locking (see also File Handles)

o String Processing, Language Text Processing, Parsing, and Searching

o Option, Argument, Parameter, and Configuration File Processing

o Internationalization and Locale

o Authentication, Security, and Encryption

o World Wide Web, HTML, HTTP, CGI, MIME

o Server and Daemon Utilities

o Archiving and Compression

o Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing

o Mail and Usenet News

o Control Flow Utilities (callbacks and exceptions etc)

o File Handle and Input/Output Stream Utilities

o Miscellaneous Modules

The list of the registered CPAN sites as of this writing follows. Please note that the sorting order is alphabetical on fields:

and thus the North American servers happen to be listed between the European and the South American sites.

You should try to choose one close to you.

Europe

North America

Canada

Alberta
http://cpan.sunsite.ualberta.ca/ ftp://cpan.sunsite.ualberta.ca/pub/CPAN/

Manitoba
http://theoryx5.uwinnipeg.ca/pub/CPAN/ ftp://theoryx5.uwinnipeg.ca/pub/CPAN/

Nova Scotia
ftp://cpan.chebucto.ns.ca/pub/CPAN/

Ontario
ftp://ftp.nrc.ca/pub/CPAN/

Mexico
http://cpan.azc.uam.mx ftp://cpan.azc.uam.mx/mirrors/CPAN http://www.cpan.unam.mx/ ftp://ftp.unam.mx/pub/CPAN http://www.msg.com.mx/CPAN/ ftp://ftp.msg.com.mx/pub/CPAN/

United States

Alabama
http://mirror.hiwaay.net/CPAN/ ftp://mirror.hiwaay.net/CPAN/

California
http://cpan.develooper.com/ http://www.cpan.org/ ftp://cpan.valueclick.com/pub/CPAN/ http://www.mednor.net/ftp/pub/mirrors/CPAN/ ftp://ftp.mednor.net/pub/mirrors/CPAN/ http://mirrors.gossamer-threads.com/CPAN ftp://cpan.nas.nasa.gov/pub/perl/CPAN/ http://mirrors.kernel.org/cpan/ ftp://mirrors.kernel.org/pub/CPAN http://cpan-sj.viaverio.com/ ftp://cpan-sj.viaverio.com/pub/CPAN/ http://cpan.digisle.net/ ftp://cpan.digisle.net/pub/CPAN http://www.perl.com/CPAN/ http://www.uberlan.net/CPAN

Colorado
ftp://ftp.cs.colorado.edu/pub/perl/CPAN/ http://cpan.four10.com

Delaware
http://ftp.lug.udel.edu/pub/CPAN ftp://ftp.lug.udel.edu/pub/CPAN

District of Columbia
ftp://ftp.dc.aleron.net/pub/CPAN/

Florida
ftp://ftp.cise.ufl.edu/pub/mirrors/CPAN/ http://mirror.csit.fsu.edu/pub/CPAN/ ftp://mirror.csit.fsu.edu/pub/CPAN/ http://cpan.mirrors.nks.net/

Indiana
ftp://ftp.uwsg.iu.edu/pub/perl/CPAN/ http://cpan.netnitco.net/ ftp://cpan.netnitco.net/pub/mirrors/CPAN/ http://archive.progeny.com/CPAN/ ftp://archive.progeny.com/CPAN/ http://fx.saintjoe.edu/pub/CPAN ftp://ftp.saintjoe.edu/pub/CPAN http://csociety-ftp.ecn.purdue.edu/pub/CPAN ftp://csociety-ftp.ecn.purdue.edu/pub/CPAN

Kentucky
http://cpan.uky.edu/ ftp://cpan.uky.edu/pub/CPAN/ http://slugsite.louisville.edu/cpan ftp://slugsite.louisville.edu/CPAN

Massachusetts
http://mirrors.towardex.com/CPAN ftp://mirrors.towardex.com/pub/CPAN ftp://ftp.ccs.neu.edu/net/mirrors/ftp.funet.fi/pub/languages/perl/CPAN/

Michigan
ftp://cpan.cse.msu.edu/ http://cpan.calvin.edu/pub/CPAN ftp://cpan.calvin.edu/pub/CPAN

Nevada
http://www.oss.redundant.com/pub/CPAN ftp://www.oss.redundant.com/pub/CPAN

New Jersey
http://ftp.cpanel.net/pub/CPAN/ ftp://ftp.cpanel.net/pub/CPAN/ http://cpan.teleglobe.net/ ftp://cpan.teleglobe.net/pub/CPAN

New York
http://cpan.belfry.net/ http://cpan.erlbaum.net/ ftp://cpan.erlbaum.net/ http://cpan.thepirtgroup.com/ ftp://cpan.thepirtgroup.com/ ftp://ftp.stealth.net/pub/CPAN/ http://www.rge.com/pub/languages/perl/ ftp://ftp.rge.com/pub/languages/perl/

North Carolina
http://www.ibiblio.org/pub/languages/perl/CPAN ftp://ftp.ibiblio.org/pub/languages/perl/CPAN ftp://ftp.duke.edu/pub/perl/ ftp://ftp.ncsu.edu/pub/mirror/CPAN/

Oklahoma
ftp://ftp.ou.edu/mirrors/CPAN/

Oregon
ftp://ftp.orst.edu/pub/CPAN

Pennsylvania
http://ftp.epix.net/CPAN/ ftp://ftp.epix.net/pub/languages/perl/ http://mirrors.phenominet.com/pub/CPAN/ ftp://mirrors.phenominet.com/pub/CPAN/ http://cpan.pair.com/ ftp://cpan.pair.com/pub/CPAN/ ftp://carroll.cac.psu.edu/pub/CPAN/

Tennessee
ftp://ftp.sunsite.utk.edu/pub/CPAN/

Texas
http://ftp.sedl.org/pub/mirrors/CPAN/ http://www.binarycode.org/cpan ftp://mirror.telentente.com/pub/CPAN http://mirrors.theonlinerecordstore.com/CPAN

Utah
ftp://mirror.xmission.com/CPAN/

Virginia
http://cpan-du.viaverio.com/ ftp://cpan-du.viaverio.com/pub/CPAN/ http://mirrors.rcn.net/pub/lang/CPAN/ ftp://mirrors.rcn.net/pub/lang/CPAN/ http://perl.secsup.org/ ftp://perl.secsup.org/pub/perl/ http://noc.cvaix.com/mirrors/CPAN/

Washington
http://cpan.llarian.net/ ftp://cpan.llarian.net/pub/CPAN/ http://cpan.mirrorcentral.com/ ftp://ftp.mirrorcentral.com/pub/CPAN/ ftp://ftp-mirror.internap.com/pub/CPAN/

Wisconsin
http://mirror.sit.wisc.edu/pub/CPAN/ ftp://mirror.sit.wisc.edu/pub/CPAN/ http://mirror.aphix.com/CPAN ftp://mirror.aphix.com/pub/CPAN

Oceania

Australia
http://ftp.planetmirror.com/pub/CPAN/ ftp://ftp.planetmirror.com/pub/CPAN/ ftp://mirror.aarnet.edu.au/pub/perl/CPAN/ ftp://cpan.topend.com.au/pub/CPAN/ http://cpan.mirrors.ilisys.com.au

New Zealand
ftp://ftp.auckland.ac.nz/pub/perl/CPAN/

United States
http://aniani.ifa.hawaii.edu/CPAN/ ftp://aniani.ifa.hawaii.edu/CPAN/

South America

Argentina
ftp://mirrors.bannerlandia.com.ar/mirrors/CPAN/ http://www.linux.org.ar/mirrors/cpan ftp://ftp.linux.org.ar/mirrors/cpan

Brazil
ftp://cpan.pop-mg.com.br/pub/CPAN/ ftp://ftp.matrix.com.br/pub/perl/CPAN/ http://cpan.hostsul.com.br/ ftp://cpan.hostsul.com.br/

Chile
http://cpan.netglobalis.net/ ftp://cpan.netglobalis.net/pub/CPAN/

\s-1RSYNC\s0 Mirrors


                      www.linux.org.ar::cpan
                      theoryx5.uwinnipeg.ca::CPAN
                      ftp.shellhung.org::CPAN
                      rsync.nic.funet.fi::CPAN
                      ftp.u-paris10.fr::CPAN
                      mir1.ovh.net::CPAN
                      rsync://ftp.crihan.fr::CPAN
                      ftp.gwdg.de::FTP/languages/perl/CPAN/
                      ftp.leo.org::CPAN
                      ftp.cbn.net.id::CPAN
                      rsync://ftp.heanet.ie/mirrors/ftp.perl.org/pub/CPAN
                      ftp.iglu.org.il::CPAN
                      gusp.dyndns.org::cpan
                      ftp.kddlabs.co.jp::cpan
                      ftp.ayamura.org::pub/CPAN/
                      mirror.leafbug.org::CPAN
                      rsync.en.com.sg::CPAN
                      mirror.averse.net::cpan
                      rsync.oss.eznetsols.org
                      ftp.kr.FreeBSD.org::CPAN
                      ftp.solnet.ch::CPAN
                      cpan.cdpa.nsysu.edu.tw::CPAN
                      cpan.teleglobe.net::CPAN
                      rsync://rsync.mirror.anlx.net::CPAN
                      ftp.sedl.org::cpan
                      ibiblio.org::CPAN
                      cpan-du.viaverio.com::CPAN
                      aniani.ifa.hawaii.edu::CPAN
                      archive.progeny.com::CPAN
                      rsync://slugsite.louisville.edu::CPAN
                      mirror.aphix.com::CPAN
                      cpan.teleglobe.net::CPAN
                      ftp.lug.udel.edu::cpan
                      mirrors.kernel.org::mirrors/CPAN
                      mirrors.phenominet.com::CPAN
                      cpan.pair.com::CPAN
                      cpan-sj.viaverio.com::CPAN
                      mirror.csit.fsu.edu::CPAN
                      csociety-ftp.ecn.purdue.edu::CPAN

For an up-to-date listing of CPAN sites, see http://www.cpan.org/SITES or ftp://www.cpan.org/SITES .

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, perltoot, and AutoLoader for details about the AUTOLOAD mechanism.

Guidelines for Module Creation

o 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.

o 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 (see perlbot for more details).
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 the perlstyle(1) manual.
Always use -w.

o 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.

o 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.

o 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 in any doubt ask for suggestions in comp.lang.perl.misc.
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.

o 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. Comp.lang.perl.misc is read by just about all the people who develop modules and it’s the best place to ask.
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!

o 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:

o A description of the module/package/extension etc.

o A copyright notice - see below.

o Prerequisites - what else you may need to have.

o How to build it - possible changes to Makefile.PL etc.

o How to install it.

o Recent changes in this release, especially incompatibilities

o 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.

o 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.

o 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 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.

o How to release and distribute a module.
It’s good idea to post an announcement of the availability of your module (or the module itself if small) to the comp.lang.perl.announce Usenet newsgroup. This will at least ensure very wide once-off distribution.
If possible, register the module with CPAN. You should include details of its location in your announcement.
Some notes about ftp archives: Please use a long descriptive file name that includes the version number. Most incoming directories will not be readable/listable, i.e., you won’t be able to see your file after uploading it. Remember to send your email notification message as soon as possible after uploading else your file may get deleted automatically. Allow time for the file to be processed and/or check the file has been processed before announcing its location.
FTP Archives for Perl Modules:
Follow the instructions and links on:

http://www.cpan.org/modules/00modlist.long.html http://www.cpan.org/modules/04pause.html

or upload to one of these sites:

https://pause.kbx.de/pause/ http://pause.perl.org/pause/

and notify <modules@perl.org>.
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!
Please remember to send me an updated entry for the Module list!

o 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

o 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.

o 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?

o 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.

o 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:

o Adds the standard Module prologue lines

o Converts package specifiers from ’ to ::

o Converts die(...) to croak(...)

o 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

o Complete applications rarely belong in the Perl Module Library.

o 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.

o Break-out the reusable code into one or more separate module files.

o Take the opportunity to reconsider and redesign the interfaces.

o 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.