Current Path : /usr/local/lib/perl5/5.8.9/pod/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //usr/local/lib/perl5/5.8.9/pod/perlmodlib.pod |
=for maintainers Generated by perlmodlib.PL -- DO NOT EDIT! =head1 NAME perlmodlib - constructing new Perl modules and finding existing ones =head1 THE PERL MODULE LIBRARY Many modules are included in the Perl distribution. These are described below, and all end in F<.pm>. You may discover compiled library files (usually ending in F<.so>) or small pieces of modules to be autoloaded (ending in F<.al>); these were automatically generated by the installation process. You may also discover files in the library directory that end in either F<.pl> or F<.ph>. These are old libraries supplied so that old programs that use them still run. The F<.pl> files will all eventually be converted into standard modules, and the F<.ph> files made by B<h2ph> will probably end up as extension modules made by B<h2xs>. (Some F<.ph> values may already be available through the POSIX, Errno, or Fcntl modules.) The B<pl2pm> file in the distribution may help in your conversion, but it's just a mechanical process and therefore far from bulletproof. =head2 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 C<use>, or C<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 C<$^H> hints variable. Others affect the current package instead, like C<use vars> and C<use subs>, which allow you to predeclare a variables or subroutines within a particular I<file> rather than just a block. Such declarations are effective for the entire file for which they were declared. You cannot rescind them with C<no vars> or C<no subs>. The following pragmas are defined (and have their own documentation). =over 12 =item attributes Get/set subroutine or variable attributes =item attrs Set/get attributes of a subroutine (deprecated) =item autouse Postpone load of modules until a function is used =item base Establish an ISA relationship with base classes at compile time =item bigint Transparent BigInteger support for Perl =item bignum Transparent BigNumber support for Perl =item bigrat Transparent BigNumber/BigRational support for Perl =item blib Use MakeMaker's uninstalled version of a package =item bytes Force byte semantics rather than character semantics =item charnames Define character names for C<\N{named}> string literal escapes =item constant Declare constants =item diagnostics Produce verbose warning diagnostics =item encoding Allows you to write your script in non-ascii or non-utf8 =item fields Compile-time class fields =item filetest Control the filetest permission operators =item if C<use> a Perl module if a condition holds =item integer Use integer arithmetic instead of floating point =item less Request less of something from the compiler =item lib Manipulate @INC at compile time =item locale Use and avoid POSIX locales for built-in operations =item open Set default PerlIO layers for input and output =item ops Restrict unsafe operations when compiling =item overload Package for overloading Perl operations =item re Alter regular expression behaviour =item sigtrap Enable simple signal handling =item sort Control sort() behaviour =item strict Restrict unsafe constructs =item subs Predeclare sub names =item threads Perl interpreter-based threads =item threads::shared Perl extension for sharing data structures between threads =item utf8 Enable/disable UTF-8 (or UTF-EBCDIC) in source code =item vars Predeclare global variable names (obsolete) =item vmsish Control VMS-specific language features =item warnings Control optional warnings =item warnings::register Warnings import function =back =head2 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. =over 12 =item AnyDBM_File Provide framework for multiple DBMs =item Attribute::Handlers Simpler definition of attribute handlers =item AutoLoader Load subroutines only on demand =item AutoSplit Split a package for autoloading =item B The Perl Compiler =item B::Asmdata Autogenerated data about Perl ops, used to generate bytecode =item B::Assembler Assemble Perl bytecode =item B::Bblock Walk basic blocks =item B::Bytecode Perl compiler's bytecode backend =item B::C Perl compiler's C backend =item B::CC Perl compiler's optimized C translation backend =item B::Concise Walk Perl syntax tree, printing concise info about ops =item B::Debug Walk Perl syntax tree, printing debug info about ops =item B::Deparse Perl compiler backend to produce perl code =item B::Disassembler Disassemble Perl bytecode =item B::Lint Perl lint =item B::Lint::Debug Adds debugging stringification to B:: =item B::Showlex Show lexical variables used in functions or files =item B::Stackobj Helper module for CC backend =item B::Stash Show what stashes are loaded =item B::Terse Walk Perl syntax tree, printing terse info about ops =item B::Xref Generates cross reference reports for Perl programs =item Benchmark Benchmark running times of Perl code =item ByteLoader Load byte compiled perl code =item CGI Simple Common Gateway Interface Class =item CGI::Apache Backward compatibility module for CGI.pm =item CGI::Carp CGI routines for writing to the HTTPD (or other) error log =item CGI::Cookie Interface to Netscape Cookies =item CGI::Fast CGI Interface for Fast CGI =item CGI::Pretty Module to produce nicely formatted HTML code =item CGI::Push Simple Interface to Server Push =item CGI::Switch Backward compatibility module for defunct CGI::Switch =item CGI::Util Internal utilities used by CGI module =item CORE Pseudo-namespace for Perl's core routines =item CPAN Query, download and build perl modules from CPAN sites =item CPAN::API::HOWTO A recipe book for programming with CPAN.pm =item CPAN::FirstTime Utility for CPAN::Config file Initialization =item CPAN::Kwalify Interface between CPAN.pm and Kwalify.pm =item CPAN::Nox Wrapper around CPAN.pm without using any XS module =item CPAN::Version Utility functions to compare CPAN versions =item Carp Warn of errors (from perspective of caller) =item Carp::Heavy Heavy machinery, no user serviceable parts inside =item Class::ISA Report the search path for a class's ISA tree =item Class::Struct Declare struct-like datatypes as Perl classes =item Config Access Perl configuration information =item Cwd Get pathname of current working directory =item DB Programmatic interface to the Perl debugging API (draft, subject to =item DBM_Filter Filter DBM keys/values =item DBM_Filter::compress Filter for DBM_Filter =item DBM_Filter::encode Filter for DBM_Filter =item DBM_Filter::int32 Filter for DBM_Filter =item DBM_Filter::null Filter for DBM_Filter =item DBM_Filter::utf8 Filter for DBM_Filter =item DB_File Perl5 access to Berkeley DB version 1.x =item Data::Dumper Stringified perl data structures, suitable for both printing and C<eval> =item Devel::DProf A Perl code profiler =item Devel::InnerPackage Find all the inner packages of a package =item Devel::Peek A data debugging tool for the XS programmer =item Devel::SelfStubber Generate stubs for a SelfLoading module =item Digest Modules that calculate message digests =item Digest::MD5 Perl interface to the MD5 Algorithm =item Digest::base Digest base class =item Digest::file Calculate digests of files =item DirHandle Supply object methods for directory handles =item Dumpvalue Provides screen dump of Perl data. =item DynaLoader Dynamically load C libraries into Perl code =item Encode Character encodings =item Encode::Alias Alias definitions to encodings =item Encode::Byte Single Byte Encodings =item Encode::CJKConstants Internally used by Encode::??::ISO_2022_* =item Encode::CN China-based Chinese Encodings =item Encode::CN::HZ Internally used by Encode::CN =item Encode::Config Internally used by Encode =item Encode::EBCDIC EBCDIC Encodings =item Encode::Encoder Object Oriented Encoder =item Encode::Encoding Encode Implementation Base Class =item Encode::GSM0338 ESTI GSM 03.38 Encoding =item Encode::Guess Guesses encoding from data =item Encode::JP Japanese Encodings =item Encode::JP::H2Z Internally used by Encode::JP::2022_JP* =item Encode::JP::JIS7 Internally used by Encode::JP =item Encode::KR Korean Encodings =item Encode::KR::2022_KR Internally used by Encode::KR =item Encode::MIME::Header MIME 'B' and 'Q' header encoding =item Encode::MIME::Name Internally used by Encode =item Encode::PerlIO A detailed document on Encode and PerlIO =item Encode::Supported Encodings supported by Encode =item Encode::Symbol Symbol Encodings =item Encode::TW Taiwan-based Chinese Encodings =item Encode::Unicode Various Unicode Transformation Formats =item Encode::Unicode::UTF7 UTF-7 encoding =item English Use nice English (or awk) names for ugly punctuation variables =item Env Perl module that imports environment variables as scalars or arrays =item Errno System errno constants =item Exporter Implements default import method for modules =item Exporter::Heavy Exporter guts =item ExtUtils::Command Utilities to replace common UNIX commands in Makefiles etc. =item ExtUtils::Command::MM Commands for the MM's to use in Makefiles =item ExtUtils::Constant Generate XS code to import C header constants =item ExtUtils::Constant::Base Base class for ExtUtils::Constant objects =item ExtUtils::Constant::Utils Helper functions for ExtUtils::Constant =item ExtUtils::Constant::XS Base class for ExtUtils::Constant objects =item ExtUtils::Embed Utilities for embedding Perl in C/C++ applications =item ExtUtils::Install Install files from here to there =item ExtUtils::Installed Inventory management of installed modules =item ExtUtils::Liblist Determine libraries to use and how to use them =item ExtUtils::MM OS adjusted ExtUtils::MakeMaker subclass =item ExtUtils::MM_AIX AIX specific subclass of ExtUtils::MM_Unix =item ExtUtils::MM_Any Platform-agnostic MM methods =item ExtUtils::MM_BeOS Methods to override UN*X behaviour in ExtUtils::MakeMaker =item ExtUtils::MM_Cygwin Methods to override UN*X behaviour in ExtUtils::MakeMaker =item ExtUtils::MM_DOS DOS specific subclass of ExtUtils::MM_Unix =item ExtUtils::MM_Darwin Special behaviors for OS X =item ExtUtils::MM_MacOS Once produced Makefiles for MacOS Classic =item ExtUtils::MM_NW5 Methods to override UN*X behaviour in ExtUtils::MakeMaker =item ExtUtils::MM_OS2 Methods to override UN*X behaviour in ExtUtils::MakeMaker =item ExtUtils::MM_QNX QNX specific subclass of ExtUtils::MM_Unix =item ExtUtils::MM_UWIN U/WIN specific subclass of ExtUtils::MM_Unix =item ExtUtils::MM_Unix Methods used by ExtUtils::MakeMaker =item ExtUtils::MM_VMS Methods to override UN*X behaviour in ExtUtils::MakeMaker =item ExtUtils::MM_VOS VOS specific subclass of ExtUtils::MM_Unix =item ExtUtils::MM_Win32 Methods to override UN*X behaviour in ExtUtils::MakeMaker =item ExtUtils::MM_Win95 Method to customize MakeMaker for Win9X =item ExtUtils::MY ExtUtils::MakeMaker subclass for customization =item ExtUtils::MakeMaker Create a module Makefile =item ExtUtils::MakeMaker::Config Wrapper around Config.pm =item ExtUtils::MakeMaker::FAQ Frequently Asked Questions About MakeMaker =item ExtUtils::MakeMaker::Tutorial Writing a module with MakeMaker =item ExtUtils::MakeMaker::bytes Version-agnostic bytes.pm =item ExtUtils::MakeMaker::vmsish Platform-agnostic vmsish.pm =item ExtUtils::Manifest Utilities to write and check a MANIFEST file =item ExtUtils::Mkbootstrap Make a bootstrap file for use by DynaLoader =item ExtUtils::Mksymlists Write linker options files for dynamic extension =item ExtUtils::Packlist Manage .packlist files =item ExtUtils::ParseXS Converts Perl XS code into C code =item ExtUtils::testlib Add blib/* directories to @INC =item Fatal Replace functions with equivalents which succeed or die =item Fcntl Load the C Fcntl.h defines =item File::Basename Parse file paths into directory, filename and suffix. =item File::CheckTree Run many filetest checks on a tree =item File::Compare Compare files or filehandles =item File::Copy Copy files or filehandles =item File::DosGlob DOS like globbing and then some =item File::Find Traverse a directory tree. =item File::Glob Perl extension for BSD glob routine =item File::Path Create or remove directory trees =item File::Spec Portably perform operations on file names =item File::Spec::Cygwin Methods for Cygwin file specs =item File::Spec::Epoc Methods for Epoc file specs =item File::Spec::Functions Portably perform operations on file names =item File::Spec::Mac File::Spec for Mac OS (Classic) =item File::Spec::OS2 Methods for OS/2 file specs =item File::Spec::Unix File::Spec for Unix, base for other File::Spec modules =item File::Spec::VMS Methods for VMS file specs =item File::Spec::Win32 Methods for Win32 file specs =item File::Temp Return name and handle of a temporary file safely =item File::stat By-name interface to Perl's built-in stat() functions =item FileCache Keep more files open than the system permits =item FileHandle Supply object methods for filehandles =item Filter::Simple Simplified source filtering =item Filter::Util::Call Perl Source Filter Utility Module =item FindBin Locate directory of original perl script =item GDBM_File Perl5 access to the gdbm library. =item Getopt::Long Extended processing of command line options =item Getopt::Std Process single-character switches with switch clustering =item Hash::Util A selection of general-utility hash subroutines =item I18N::Collate Compare 8-bit scalar data according to the current locale =item I18N::LangTags Functions for dealing with RFC3066-style language tags =item I18N::LangTags::Detect Detect the user's language preferences =item I18N::LangTags::List Tags and names for human languages =item I18N::Langinfo Query locale information =item IO Load various IO modules =item IO::Dir Supply object methods for directory handles =item IO::File Supply object methods for filehandles =item IO::Handle Supply object methods for I/O handles =item IO::Pipe Supply object methods for pipes =item IO::Poll Object interface to system poll call =item IO::Seekable Supply seek based methods for I/O objects =item IO::Select OO interface to the select system call =item IO::Socket Object interface to socket communications =item IO::Socket::INET Object interface for AF_INET domain sockets =item IO::Socket::UNIX Object interface for AF_UNIX domain sockets =item IPC::Open2 Open a process for both reading and writing =item IPC::Open3 Open a process for reading, writing, and error handling =item IPC::SysV SysV IPC constants =item IPC::SysV::Msg SysV Msg IPC object class =item IPC::SysV::Semaphore SysV Semaphore IPC object class =item List::Util A selection of general-utility list subroutines =item Locale::Constants Constants for Locale codes =item Locale::Country ISO codes for country identification (ISO 3166) =item Locale::Currency ISO three letter codes for currency identification (ISO 4217) =item Locale::Language ISO two letter codes for language identification (ISO 639) =item Locale::Maketext Framework for localization =item Locale::Maketext::TPJ13 Article about software localization =item Locale::Script ISO codes for script identification (ISO 15924) =item MIME::Base64 Encoding and decoding of base64 strings =item MIME::QuotedPrint Encoding and decoding of quoted-printable strings =item Math::BigFloat Arbitrary size floating point math package =item Math::BigInt Arbitrary size integer/float math package =item Math::BigInt::Calc Pure Perl module to support Math::BigInt =item Math::BigInt::CalcEmu Emulate low-level math with BigInt code =item Math::BigRat Arbitrary big rational numbers =item Math::Complex Complex numbers and associated mathematical functions =item Math::Trig Trigonometric functions =item Memoize Make functions faster by trading space for time =item Memoize::AnyDBM_File Glue to provide EXISTS for AnyDBM_File for Storable use =item Memoize::Expire Plug-in module for automatic expiration of memoized values =item Memoize::ExpireFile Test for Memoize expiration semantics =item Memoize::ExpireTest Test for Memoize expiration semantics =item Memoize::NDBM_File Glue to provide EXISTS for NDBM_File for Storable use =item Memoize::SDBM_File Glue to provide EXISTS for SDBM_File for Storable use =item Memoize::Storable Store Memoized data in Storable database =item Module::CoreList What modules shipped with versions of perl =item Module::Pluggable Automatically give your module the ability to have plugins =item Module::Pluggable::Object Automatically give your module the ability to have plugins =item NDBM_File Tied access to ndbm files =item NEXT Provide a pseudo-class NEXT (et al) that allows method redispatch =item Net::Cmd Network Command class (as used by FTP, SMTP etc) =item Net::Config Local configuration data for libnet =item Net::Domain Attempt to evaluate the current host's internet name and domain =item Net::FTP FTP Client class =item Net::NNTP NNTP Client class =item Net::Netrc OO interface to users netrc file =item Net::POP3 Post Office Protocol 3 Client class (RFC1939) =item Net::Ping Check a remote host for reachability =item Net::SMTP Simple Mail Transfer Protocol Client =item Net::Time Time and daytime network client interface =item Net::hostent By-name interface to Perl's built-in gethost*() functions =item Net::libnetFAQ Libnet Frequently Asked Questions =item Net::netent By-name interface to Perl's built-in getnet*() functions =item Net::protoent By-name interface to Perl's built-in getproto*() functions =item Net::servent By-name interface to Perl's built-in getserv*() functions =item O Generic interface to Perl Compiler backends =item ODBM_File Tied access to odbm files =item Opcode Disable named opcodes when compiling perl code =item POSIX Perl interface to IEEE Std 1003.1 =item PerlIO On demand loader for PerlIO layers and root of PerlIO::* name space =item PerlIO::encoding Encoding layer =item PerlIO::scalar In-memory IO, scalar IO =item PerlIO::via Helper class for PerlIO layers implemented in perl =item PerlIO::via::QuotedPrint PerlIO layer for quoted-printable strings =item Pod::Checker Check pod documents for syntax errors =item Pod::Find Find POD documents in directory trees =item Pod::Functions Group Perl's functions a la perlfunc.pod =item Pod::Html Module to convert pod files to HTML =item Pod::InputObjects Objects representing POD input paragraphs, commands, etc. =item Pod::LaTeX Convert Pod data to formatted Latex =item Pod::Man Convert POD data to formatted *roff input =item Pod::ParseLink Parse an LE<lt>E<gt> formatting code in POD text =item Pod::ParseUtils Helpers for POD parsing and conversion =item Pod::Parser Base class for creating POD filters and translators =item Pod::Perldoc::ToChecker Let Perldoc check Pod for errors =item Pod::Perldoc::ToMan Let Perldoc render Pod as man pages =item Pod::Perldoc::ToNroff Let Perldoc convert Pod to nroff =item Pod::Perldoc::ToPod Let Perldoc render Pod as ... Pod! =item Pod::Perldoc::ToRtf Let Perldoc render Pod as RTF =item Pod::Perldoc::ToText Let Perldoc render Pod as plaintext =item Pod::Perldoc::ToTk Let Perldoc use Tk::Pod to render Pod =item Pod::Perldoc::ToXml Let Perldoc render Pod as XML =item Pod::PlainText Convert POD data to formatted ASCII text =item Pod::Plainer Perl extension for converting Pod to old style Pod. =item Pod::Select Extract selected sections of POD from input =item Pod::Text Convert POD data to formatted ASCII text =item Pod::Text::Color Convert POD data to formatted color ASCII text =item Pod::Text::Overstrike Convert POD data to formatted overstrike text =item Pod::Text::Termcap Convert POD data to ASCII text with format escapes =item Pod::Usage Print a usage message from embedded pod documentation =item SDBM_File Tied access to sdbm files =item Safe Compile and execute code in restricted compartments =item Scalar::Util A selection of general-utility scalar subroutines =item Search::Dict Search for key in dictionary file =item SelectSaver Save and restore selected file handle =item SelfLoader Load functions only on demand =item Shell Run shell commands transparently within perl =item Socket Load the C socket.h defines and structure manipulators =item Storable Persistence for Perl data structures =item Switch A switch statement for Perl =item Symbol Manipulate Perl symbols and their names =item Sys::Hostname Try every conceivable way to get hostname =item Sys::Syslog Perl interface to the UNIX syslog(3) calls =item Sys::Syslog::win32::Win32 Win32 support for Sys::Syslog =item Term::ANSIColor Color screen output using ANSI escape sequences =item Term::Cap Perl termcap interface =item Term::Complete Perl word completion module =item Term::ReadLine Perl interface to various C<readline> packages. =item Test Provides a simple framework for writing test scripts =item Test::Builder Backend for building test libraries =item Test::Builder::Module Base class for test modules =item Test::Builder::Tester Test testsuites that have been built with =item Test::Builder::Tester::Color Turn on colour in Test::Builder::Tester =item Test::Harness Run Perl standard test scripts with statistics =item Test::Harness::Assert Simple assert =item Test::Harness::Iterator Internal Test::Harness Iterator =item Test::Harness::Point Object for tracking a single test point =item Test::Harness::Results Object for tracking results from a single test file =item Test::Harness::Straps Detailed analysis of test results =item Test::Harness::TAP Documentation for the TAP format =item Test::Harness::Util Utility functions for Test::Harness::* =item Test::More Yet another framework for writing test scripts =item Test::Simple Basic utilities for writing tests. =item Test::Tutorial A tutorial about writing really basic tests =item Text::Abbrev Create an abbreviation table from a list =item Text::Balanced Extract delimited text sequences from strings. =item Text::ParseWords Parse text into an array of tokens or array of arrays =item Text::Soundex Implementation of the soundex algorithm. =item Text::Tabs Expand and unexpand tabs per the unix expand(1) and unexpand(1) =item Text::Wrap Line wrapping to form simple paragraphs =item Thread Manipulate threads in Perl (for old code only) =item Thread::Queue Thread-safe queues =item Thread::Semaphore Thread-safe semaphores =item Thread::Signal Start a thread which runs signal handlers reliably (for old code) =item Thread::Specific Thread-specific keys =item Tie::Array Base class for tied arrays =item Tie::File Access the lines of a disk file via a Perl array =item Tie::Handle Base class definitions for tied handles =item Tie::Hash Base class definitions for tied hashes =item Tie::Memoize Add data to hash when needed =item Tie::RefHash Use references as hash keys =item Tie::Scalar Base class definitions for tied scalars =item Tie::SubstrHash Fixed-table-size, fixed-key-length hashing =item Time::HiRes High resolution alarm, sleep, gettimeofday, interval timers =item Time::Local Efficiently compute time from local and GMT time =item Time::gmtime By-name interface to Perl's built-in gmtime() function =item Time::localtime By-name interface to Perl's built-in localtime() function =item Time::tm Internal object used by Time::gmtime and Time::localtime =item UNIVERSAL Base class for ALL classes (blessed references) =item Unicode::Collate Unicode Collation Algorithm =item Unicode::Normalize Unicode Normalization Forms =item Unicode::UCD Unicode character database =item User::grent By-name interface to Perl's built-in getgr*() functions =item User::pwent By-name interface to Perl's built-in getpw*() functions =item Win32 Interfaces to some Win32 API Functions =item Win32API::File Low-level access to Win32 system API calls for files/dirs. =item Win32CORE Win32 CORE function stubs =item XS::APItest Test the perl C API =item XS::Typemap Module to test the XS typemaps distributed with perl =item XSLoader Dynamically load C libraries into Perl code =back To find out I<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 B<find> program, you can use the Perl B<find2perl> program instead, which generates Perl code as output you can run through perl. If you have a B<man> program but it doesn't find your modules, you'll have to fix your manpath. See L<perl> for details. If you have no system B<man> command, you might try the B<perldoc> program. Note also that the command C<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.) =head2 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. =head1 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: =over =item * Language Extensions and Documentation Tools =item * Development Support =item * Operating System Interfaces =item * Networking, Device Control (modems) and InterProcess Communication =item * Data Types and Data Type Utilities =item * Database Interfaces =item * User Interfaces =item * Interfaces to / Emulations of Other Programming Languages =item * File Names, File Systems and File Locking (see also File Handles) =item * String Processing, Language Text Processing, Parsing, and Searching =item * Option, Argument, Parameter, and Configuration File Processing =item * Internationalization and Locale =item * Authentication, Security, and Encryption =item * World Wide Web, HTML, HTTP, CGI, MIME =item * Server and Daemon Utilities =item * Archiving and Compression =item * Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing =item * Mail and Usenet News =item * Control Flow Utilities (callbacks and exceptions etc) =item * File Handle and Input/Output Stream Utilities =item * Miscellaneous Modules =back The list of the registered CPAN sites as of this writing follows. Please note that the sorting order is alphabetical on fields: Continent | |-->Country | |-->[state/province] | |-->ftp | |-->[http] 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. =head2 Africa =over 4 =item South Africa http://ftp.rucus.ru.ac.za/pub/perl/CPAN/ ftp://ftp.rucus.ru.ac.za/pub/perl/CPAN/ ftp://ftp.is.co.za/programming/perl/CPAN/ ftp://ftp.saix.net/pub/CPAN/ ftp://ftp.sun.ac.za/CPAN/CPAN/ =back =head2 Asia =over 4 =item China http://cpan.linuxforum.net/ http://cpan.shellhung.org/ ftp://ftp.shellhung.org/pub/CPAN ftp://mirrors.hknet.com/CPAN =item Indonesia http://mirrors.tf.itb.ac.id/cpan/ http://cpan.cbn.net.id/ ftp://ftp.cbn.net.id/mirror/CPAN =item Israel ftp://ftp.iglu.org.il/pub/CPAN/ http://cpan.lerner.co.il/ http://bioinfo.weizmann.ac.il/pub/software/perl/CPAN/ ftp://bioinfo.weizmann.ac.il/pub/software/perl/CPAN/ =item Japan ftp://ftp.u-aizu.ac.jp/pub/CPAN ftp://ftp.kddlabs.co.jp/CPAN/ ftp://ftp.ayamura.org/pub/CPAN/ ftp://ftp.jaist.ac.jp/pub/lang/perl/CPAN/ http://ftp.cpan.jp/ ftp://ftp.cpan.jp/CPAN/ ftp://ftp.dti.ad.jp/pub/lang/CPAN/ ftp://ftp.ring.gr.jp/pub/lang/perl/CPAN/ =item Malaysia http://cpan.MyBSD.org.my http://mirror.leafbug.org/pub/CPAN http://ossig.mncc.com.my/mirror/pub/CPAN =item Russian Federation http://cpan.tomsk.ru ftp://cpan.tomsk.ru/ =item Saudi Arabia ftp://ftp.isu.net.sa/pub/CPAN/ =item Singapore http://CPAN.en.com.sg/ ftp://cpan.en.com.sg/ http://mirror.averse.net/pub/CPAN ftp://mirror.averse.net/pub/CPAN http://cpan.oss.eznetsols.org ftp://ftp.oss.eznetsols.org/cpan =item South Korea http://CPAN.bora.net/ ftp://ftp.bora.net/pub/CPAN/ http://mirror.kr.FreeBSD.org/CPAN ftp://ftp.kr.FreeBSD.org/pub/CPAN =item Taiwan ftp://ftp.nctu.edu.tw/UNIX/perl/CPAN http://cpan.cdpa.nsysu.edu.tw/ ftp://cpan.cdpa.nsysu.edu.tw/pub/CPAN http://ftp.isu.edu.tw/pub/CPAN ftp://ftp.isu.edu.tw/pub/CPAN ftp://ftp1.sinica.edu.tw/pub1/perl/CPAN/ http://ftp.tku.edu.tw/pub/CPAN/ ftp://ftp.tku.edu.tw/pub/CPAN/ =item Thailand ftp://ftp.loxinfo.co.th/pub/cpan/ ftp://ftp.cs.riubon.ac.th/pub/mirrors/CPAN/ =back =head2 Central America =over 4 =item Costa Rica http://ftp.ucr.ac.cr/Unix/CPAN/ ftp://ftp.ucr.ac.cr/pub/Unix/CPAN/ =back =head2 Europe =over 4 =item Austria http://cpan.inode.at/ ftp://cpan.inode.at ftp://ftp.tuwien.ac.at/pub/CPAN/ =item Belgium http://ftp.easynet.be/pub/CPAN/ ftp://ftp.easynet.be/pub/CPAN/ http://cpan.skynet.be ftp://ftp.cpan.skynet.be/pub/CPAN ftp://ftp.kulnet.kuleuven.ac.be/pub/mirror/CPAN/ =item Bosnia and Herzegovina http://cpan.blic.net/ =item Bulgaria http://cpan.online.bg ftp://cpan.online.bg/cpan http://cpan.zadnik.org ftp://ftp.zadnik.org/mirrors/CPAN/ http://cpan.lirex.net/ ftp://ftp.lirex.net/pub/mirrors/CPAN =item Croatia http://ftp.linux.hr/pub/CPAN/ ftp://ftp.linux.hr/pub/CPAN/ =item Czech Republic ftp://ftp.fi.muni.cz/pub/CPAN/ ftp://sunsite.mff.cuni.cz/MIRRORS/ftp.funet.fi/pub/languages/perl/CPAN/ =item Denmark http://mirrors.sunsite.dk/cpan/ ftp://sunsite.dk/mirrors/cpan/ http://cpan.cybercity.dk http://www.cpan.dk/CPAN/ ftp://www.cpan.dk/ftp.cpan.org/CPAN/ =item Estonia ftp://ftp.ut.ee/pub/languages/perl/CPAN/ =item Finland ftp://ftp.funet.fi/pub/languages/perl/CPAN/ http://mirror.eunet.fi/CPAN =item France http://www.enstimac.fr/Perl/CPAN http://ftp.u-paris10.fr/perl/CPAN ftp://ftp.u-paris10.fr/perl/CPAN http://cpan.mirrors.easynet.fr/ ftp://cpan.mirrors.easynet.fr/pub/ftp.cpan.org/ ftp://ftp.club-internet.fr/pub/perl/CPAN/ http://fr.cpan.org/ ftp://ftp.lip6.fr/pub/perl/CPAN/ ftp://ftp.oleane.net/pub/mirrors/CPAN/ ftp://ftp.pasteur.fr/pub/computing/CPAN/ http://mir2.ovh.net/ftp.cpan.org ftp://mir1.ovh.net/ftp.cpan.org http://ftp.crihan.fr/mirrors/ftp.cpan.org/ ftp://ftp.crihan.fr/mirrors/ftp.cpan.org/ http://ftp.u-strasbg.fr/CPAN ftp://ftp.u-strasbg.fr/CPAN ftp://cpan.cict.fr/pub/CPAN/ ftp://ftp.uvsq.fr/pub/perl/CPAN/ =item Germany ftp://ftp.rub.de/pub/CPAN/ ftp://ftp.freenet.de/pub/ftp.cpan.org/pub/CPAN/ ftp://ftp.uni-erlangen.de/pub/source/CPAN/ ftp://ftp-stud.fht-esslingen.de/pub/Mirrors/CPAN http://pandemonium.tiscali.de/pub/CPAN/ ftp://pandemonium.tiscali.de/pub/CPAN/ http://ftp.gwdg.de/pub/languages/perl/CPAN/ ftp://ftp.gwdg.de/pub/languages/perl/CPAN/ ftp://ftp.uni-hamburg.de/pub/soft/lang/perl/CPAN/ ftp://ftp.leo.org/pub/CPAN/ http://cpan.noris.de/ ftp://cpan.noris.de/pub/CPAN/ ftp://ftp.mpi-sb.mpg.de/pub/perl/CPAN/ ftp://ftp.gmd.de/mirrors/CPAN/ =item Greece ftp://ftp.acn.gr/pub/lang/perl ftp://ftp.forthnet.gr/pub/languages/perl/CPAN ftp://ftp.ntua.gr/pub/lang/perl/ =item Hungary http://ftp.kfki.hu/packages/perl/CPAN/ ftp://ftp.kfki.hu/pub/packages/perl/CPAN/ =item Iceland http://ftp.rhnet.is/pub/CPAN/ ftp://ftp.rhnet.is/pub/CPAN/ =item Ireland http://cpan.indigo.ie/ ftp://cpan.indigo.ie/pub/CPAN/ http://ftp.heanet.ie/mirrors/ftp.perl.org/pub/CPAN ftp://ftp.heanet.ie/mirrors/ftp.perl.org/pub/CPAN http://sunsite.compapp.dcu.ie/pub/perl/ ftp://sunsite.compapp.dcu.ie/pub/perl/ =item Italy http://cpan.nettuno.it/ http://gusp.dyndns.org/CPAN/ ftp://gusp.dyndns.org/pub/CPAN http://softcity.iol.it/cpan ftp://softcity.iol.it/pub/cpan ftp://ftp.unina.it/pub/Other/CPAN/CPAN/ ftp://ftp.unipi.it/pub/mirror/perl/CPAN/ ftp://cis.uniRoma2.it/CPAN/ ftp://ftp.edisontel.it/pub/CPAN_Mirror/ http://cpan.flashnet.it/ ftp://ftp.flashnet.it/pub/CPAN/ =item Latvia http://kvin.lv/pub/CPAN/ =item Lithuania ftp://ftp.unix.lt/pub/CPAN/ =item Netherlands ftp://download.xs4all.nl/pub/mirror/CPAN/ ftp://ftp.nl.uu.net/pub/CPAN/ ftp://ftp.nluug.nl/pub/languages/perl/CPAN/ http://cpan.cybercomm.nl/ ftp://mirror.cybercomm.nl/pub/CPAN ftp://mirror.vuurwerk.nl/pub/CPAN/ ftp://ftp.cpan.nl/pub/CPAN/ http://ftp.easynet.nl/mirror/CPAN ftp://ftp.easynet.nl/mirror/CPAN http://archive.cs.uu.nl/mirror/CPAN/ ftp://ftp.cs.uu.nl/mirror/CPAN/ =item Norway ftp://ftp.uninett.no/pub/languages/perl/CPAN ftp://ftp.uit.no/pub/languages/perl/cpan/ =item Poland ftp://ftp.mega.net.pl/CPAN ftp://ftp.man.torun.pl/pub/doc/CPAN/ ftp://sunsite.icm.edu.pl/pub/CPAN/ =item Portugal ftp://ftp.ua.pt/pub/CPAN/ ftp://perl.di.uminho.pt/pub/CPAN/ http://cpan.dei.uc.pt/ ftp://ftp.dei.uc.pt/pub/CPAN ftp://ftp.nfsi.pt/pub/CPAN http://ftp.linux.pt/pub/mirrors/CPAN ftp://ftp.linux.pt/pub/mirrors/CPAN http://cpan.ip.pt/ ftp://cpan.ip.pt/pub/cpan/ http://cpan.telepac.pt/ ftp://ftp.telepac.pt/pub/cpan/ =item Romania ftp://ftp.bio-net.ro/pub/CPAN ftp://ftp.kappa.ro/pub/mirrors/ftp.perl.org/pub/CPAN/ ftp://ftp.lug.ro/CPAN ftp://ftp.roedu.net/pub/CPAN/ ftp://ftp.dntis.ro/pub/cpan/ ftp://ftp.iasi.roedu.net/pub/mirrors/ftp.cpan.org/ http://cpan.ambra.ro/ ftp://ftp.ambra.ro/pub/CPAN ftp://ftp.dnttm.ro/pub/CPAN/ ftp://ftp.lasting.ro/pub/CPAN ftp://ftp.timisoara.roedu.net/mirrors/CPAN/ =item Russia ftp://ftp.chg.ru/pub/lang/perl/CPAN/ http://cpan.rinet.ru/ ftp://cpan.rinet.ru/pub/mirror/CPAN/ ftp://ftp.aha.ru/pub/CPAN/ ftp://ftp.corbina.ru/pub/CPAN/ http://cpan.sai.msu.ru/ ftp://ftp.sai.msu.su/pub/lang/perl/CPAN/ =item Slovakia ftp://ftp.cvt.stuba.sk/pub/CPAN/ =item Slovenia ftp://ftp.arnes.si/software/perl/CPAN/ =item Spain http://cpan.imasd.elmundo.es/ ftp://ftp.rediris.es/mirror/CPAN/ ftp://ftp.ri.telefonica-data.net/CPAN ftp://ftp.etse.urv.es/pub/perl/ =item Sweden http://ftp.du.se/CPAN/ ftp://ftp.du.se/pub/CPAN/ http://mirror.dataphone.se/CPAN ftp://mirror.dataphone.se/pub/CPAN ftp://ftp.sunet.se/pub/lang/perl/CPAN/ =item Switzerland http://cpan.mirror.solnet.ch/ ftp://ftp.solnet.ch/mirror/CPAN/ ftp://ftp.danyk.ch/CPAN/ ftp://sunsite.cnlab-switch.ch/mirror/CPAN/ =item Turkey http://ftp.ulak.net.tr/perl/CPAN/ ftp://ftp.ulak.net.tr/perl/CPAN ftp://sunsite.bilkent.edu.tr/pub/languages/CPAN/ =item Ukraine http://cpan.org.ua/ ftp://cpan.org.ua/ ftp://ftp.perl.org.ua/pub/CPAN/ http://no-more.kiev.ua/CPAN/ ftp://no-more.kiev.ua/pub/CPAN/ =item United Kingdom http://www.mirror.ac.uk/sites/ftp.funet.fi/pub/languages/perl/CPAN ftp://ftp.mirror.ac.uk/sites/ftp.funet.fi/pub/languages/perl/CPAN/ http://cpan.teleglobe.net/ ftp://cpan.teleglobe.net/pub/CPAN http://cpan.mirror.anlx.net/ ftp://ftp.mirror.anlx.net/CPAN/ http://cpan.etla.org/ ftp://cpan.etla.org/pub/CPAN ftp://ftp.demon.co.uk/pub/CPAN/ http://cpan.m.flirble.org/ ftp://ftp.flirble.org/pub/languages/perl/CPAN/ ftp://ftp.plig.org/pub/CPAN/ http://cpan.hambule.co.uk/ http://cpan.mirrors.clockerz.net/ ftp://ftp.clockerz.net/pub/CPAN/ ftp://usit.shef.ac.uk/pub/packages/CPAN/ =back =head2 North America =over 4 =item Canada =over 8 =item Alberta http://cpan.sunsite.ualberta.ca/ ftp://cpan.sunsite.ualberta.ca/pub/CPAN/ =item Manitoba http://theoryx5.uwinnipeg.ca/pub/CPAN/ ftp://theoryx5.uwinnipeg.ca/pub/CPAN/ =item Nova Scotia ftp://cpan.chebucto.ns.ca/pub/CPAN/ =item Ontario ftp://ftp.nrc.ca/pub/CPAN/ =back =item 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/ =item United States =over 8 =item Alabama http://mirror.hiwaay.net/CPAN/ ftp://mirror.hiwaay.net/CPAN/ =item 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 =item Colorado ftp://ftp.cs.colorado.edu/pub/perl/CPAN/ http://cpan.four10.com =item Delaware http://ftp.lug.udel.edu/pub/CPAN ftp://ftp.lug.udel.edu/pub/CPAN =item District of Columbia ftp://ftp.dc.aleron.net/pub/CPAN/ =item 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/ =item 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 =item Kentucky http://cpan.uky.edu/ ftp://cpan.uky.edu/pub/CPAN/ http://slugsite.louisville.edu/cpan ftp://slugsite.louisville.edu/CPAN =item 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/ =item Michigan ftp://cpan.cse.msu.edu/ http://cpan.calvin.edu/pub/CPAN ftp://cpan.calvin.edu/pub/CPAN =item Nevada http://www.oss.redundant.com/pub/CPAN ftp://www.oss.redundant.com/pub/CPAN =item New Jersey http://ftp.cpanel.net/pub/CPAN/ ftp://ftp.cpanel.net/pub/CPAN/ http://cpan.teleglobe.net/ ftp://cpan.teleglobe.net/pub/CPAN =item 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/ =item 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/ =item Oklahoma ftp://ftp.ou.edu/mirrors/CPAN/ =item Oregon ftp://ftp.orst.edu/pub/CPAN =item 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/ =item Tennessee ftp://ftp.sunsite.utk.edu/pub/CPAN/ =item Texas http://ftp.sedl.org/pub/mirrors/CPAN/ http://www.binarycode.org/cpan ftp://mirror.telentente.com/pub/CPAN http://mirrors.theonlinerecordstore.com/CPAN =item Utah ftp://mirror.xmission.com/CPAN/ =item 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/ =item 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/ =item 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 =back =back =head2 Oceania =over 4 =item 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 =item New Zealand ftp://ftp.auckland.ac.nz/pub/perl/CPAN/ =item United States http://aniani.ifa.hawaii.edu/CPAN/ ftp://aniani.ifa.hawaii.edu/CPAN/ =back =head2 South America =over 4 =item Argentina ftp://mirrors.bannerlandia.com.ar/mirrors/CPAN/ http://www.linux.org.ar/mirrors/cpan ftp://ftp.linux.org.ar/mirrors/cpan =item 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/ =item Chile http://cpan.netglobalis.net/ ftp://cpan.netglobalis.net/pub/CPAN/ =back =head2 RSYNC 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 . =head1 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 F<.pm> file is required to exist. See L<perlsub>, L<perltoot>, and L<AutoLoader> for details about the AUTOLOAD mechanism. =head2 Guidelines for Module Creation =over 4 =item * 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. =item * Try to design the new module to be easy to extend and reuse. Try to C<use warnings;> (or C<use warnings qw(...);>). Remember that you can add C<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: C<die "Invalid" unless ref $ref eq 'FOO'>. Generally you can delete the C<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 C<< $r->Class::func() >> where using C<@ISA=qw(... Class ...)> and C<< $r->func() >> would work (see L<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 C<@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: C<< $obj = YOURCLASS->new(); >> into: C<< $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 B<-w>. Try to C<use strict;> (or C<use strict qw(...);>). Remember that you can add C<no strict qw(...);> to individual blocks of code that need less strictness. Always use B<-w>. Follow the guidelines in the perlstyle(1) manual. Always use B<-w>. =item * 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., C<< $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. =item * 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 C<< $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: C<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. =item * 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. =item * 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! =item * 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: =over 10 =item * A description of the module/package/extension etc. =item * A copyright notice - see below. =item * Prerequisites - what else you may need to have. =item * How to build it - possible changes to Makefile.PL etc. =item * How to install it. =item * Recent changes in this release, especially incompatibilities =item * Changes / enhancements you plan to make in the future. =back 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. =over 4 =item * 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 L<perlgpl> and L<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. =item * 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 $VERSION. This should be a floating point number with at least two digits after the decimal (i.e., hundredths, e.g, C<$VERSION = "0.01">). Don't use a "1.3.2" style version. See L<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. =item * 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! =item * 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. =back =back =head2 Guidelines for Converting Perl 4 Library Scripts into Modules =over 4 =item * 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. =item * 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? =item * 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. =item * 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: =over 10 =item * Adds the standard Module prologue lines =item * Converts package specifiers from ' to :: =item * Converts die(...) to croak(...) =item * Several other minor changes =back 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! =back =head2 Guidelines for Reusing Application Code =over 4 =item * Complete applications rarely belong in the Perl Module Library. =item * 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. =item * Break-out the reusable code into one or more separate module files. =item * Take the opportunity to reconsider and redesign the interfaces. =item * 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) =back =head1 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 C<use RedefineTheWorld> that you're redefining the world and willing to take the consequences.