=head2 Packages
Perl provides a mechanism for alternative namespaces to protect packages
-from stomping on each others variables. In fact, apart from certain
+from stomping on each other's variables. In fact, apart from certain
magical variables, there's really no such thing as a global variable in
Perl. The package statement declares the compilation unit as being in the
given namespace. The scope of the package declaration is from the
declaration itself through the end of the enclosing block (the same scope
as the local() operator). All further unqualified dynamic identifiers
-will be in this namespace. A package statement only affects dynamic
+will be in this namespace. A package statement affects only dynamic
variables--including those you've used local() on--but I<not> lexical
variables created with my(). Typically it would be the first declaration
in a file to be included by the C<require> or C<use> operator. You can
-switch into a package in more than one place; it merely influences which
+switch into a package in more than one place; it influences merely which
symbol table is used by the compiler for the rest of that block. You can
refer to variables and filehandles in other packages by prefixing the
identifier with the package name and a double colon:
C<$Package::Variable>. If the package name is null, the C<main> package
-as assumed. That is, C<$::sail> is equivalent to C<$main::sail>.
+is assumed. That is, C<$::sail> is equivalent to C<$main::sail>.
(The old package delimiter was a single quote, but double colon
is now the preferred delimiter, in part because it's more readable
Only identifiers starting with letters (or underscore) are stored in a
package's symbol table. All other symbols are kept in package C<main>,
including all of the punctuation variables like $_. In addition, the
-identifiers STDIN, STDOUT, STDERR, ARGV, ARGVOUT, ENV, INC and SIG are
+identifiers STDIN, STDOUT, STDERR, ARGV, ARGVOUT, ENV, INC, and SIG are
forced to be in package C<main>, even when used for other purposes than
-their built-in one. Note also that, if you have a package called C<m>,
-C<s> or C<y>, then you can't use the qualified form of an identifier
+their builtin one. Note also that, if you have a package called C<m>,
+C<s>, or C<y>, then you can't use the qualified form of an identifier
because it will be interpreted instead as a pattern match, a substitution,
or a translation.
expressions in the context of the C<main> package (or wherever you came
from). See L<perldebug>.
-See L<perlsub> for other scoping issues related to my() and local(),
+See L<perlsub> for other scoping issues related to my() and local(),
or L<perlref> regarding closures.
=head2 Symbol Tables
-The symbol table for a package happens to be stored in the associative
-array of that name appended with two colons. The main symbol table's
-name is thus C<%main::>, or C<%::> for short. Likewise the nested package
-mentioned earlier is named C<%OUTER::INNER::>.
+The symbol table for a package happens to be stored in the hash of that
+name with two colons appended. The main symbol table's name is thus
+C<%main::>, or C<%::> for short. Likewise symbol table for the nested
+package mentioned earlier is named C<%OUTER::INNER::>.
-The value in each entry of the associative array is what you are referring
-to when you use the C<*name> typeglob notation. In fact, the following
-have the same effect, though the first is more efficient because it does
-the symbol table lookups at compile time:
+The value in each entry of the hash is what you are referring to when you
+use the C<*name> typeglob notation. In fact, the following have the same
+effect, though the first is more efficient because it does the symbol
+table lookups at compile time:
- local(*main::foo) = *main::bar; local($main::{'foo'}) =
- $main::{'bar'};
+ local(*main::foo) = *main::bar;
+ local($main::{'foo'}) = $main::{'bar'};
You can use this to print out all the variables in a package, for
instance. Here is F<dumpvar.pl> from the Perl library:
*dick = *richard;
-causes variables, subroutines and file handles accessible via the
-identifier C<richard> to also be accessible via the symbol C<dick>. If
-you only want to alias a particular variable or subroutine, you can
+causes variables, subroutines, and file handles accessible via the
+identifier C<richard> to also be accessible via the identifier C<dick>. If
+you want to alias only a particular variable or subroutine, you can
assign a reference instead:
*dick = \$richard;
# now use %hashsym normally, and you
# will affect the caller's %another_hash
my %nhash = (); # do what you want
- return \%nhash;
+ return \%nhash;
}
-On return, the reference wil overwrite the hash slot in the
+On return, the reference will overwrite the hash slot in the
symbol table specified by the *some_hash typeglob. This
-is a somewhat tricky way of passing around refernces cheaply
+is a somewhat tricky way of passing around references cheaply
when you won't want to have to remember to dereference variables
explicitly.
Now you cannot alter $PI, which is probably a good thing all in all.
+You can say C<*foo{PACKAGE}> and C<*foo{NAME}> to find out what name and
+package the *foo symbol table entry comes from. This may be useful
+in a subroutine which is passed typeglobs as arguments
+
+ sub identify_typeglob {
+ my $glob = shift;
+ print 'You gave me ', *{$glob}{PACKAGE}, '::', *{$glob}{NAME}, "\n";
+ }
+ identify_typeglob *foo;
+ identify_typeglob *bar::baz;
+
+This prints
+
+ You gave me main::foo
+ You gave me bar::baz
+
+The *foo{THING} notation can also be used to obtain references to the
+individual elements of *foo, see L<perlref>.
+
=head2 Package Constructors and Destructors
There are two special subroutine definitions that function as package
multiple C<END> blocks within a file--they will execute in reverse
order of definition; that is: last in, first out (LIFO).
+Inside an C<END> subroutine C<$?> contains the value that the script is
+going to pass to C<exit()>. You can modify C<$?> to change the exit
+value of the script. Beware of changing C<$?> by accident (e.g.,, by
+running something via C<system>).
+
Note that when you use the B<-n> and B<-p> switches to Perl, C<BEGIN>
and C<END> work just as they do in B<awk>, as a degenerate case.
There is no special class syntax in Perl, but a package may function
as a class if it provides subroutines that function as methods. Such a
package may also derive some of its methods from another class package
-by listing the other package name in its @ISA array.
+by listing the other package name in its @ISA array.
For more on this, see L<perlobj>.
calls on the class and its objects, without explicit exportation of any
symbols. Or it can do a little of both.
-For example, to start a normal module called Fred, create
-a file called Fred.pm and put this at the start of it:
+For example, to start a normal module called Some::Module, create
+a file called Some/Module.pm and start with this template:
- package Fred;
- require Exporter;
- @ISA = qw(Exporter);
- @EXPORT = qw(func1 func2);
- @EXPORT_OK = qw($sally @listabob %harry func3);
+ package Some::Module; # assumes Some/Module.pm
+
+ use strict;
+
+ BEGIN {
+ use Exporter ();
+ use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
+
+ # set the version for version checking
+ $VERSION = 1.00;
+ # if using RCS/CVS, this may be preferred
+ $VERSION = do { my @r = (q$Revision: 2.21 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r }; # must be all one line, for MakeMaker
+
+ @ISA = qw(Exporter);
+ @EXPORT = qw(&func1 &func2 &func4);
+ %EXPORT_TAGS = ( ); # eg: TAG => [ qw!name1 name2! ],
+
+ # your exported package globals go here,
+ # as well as any optionally exported functions
+ @EXPORT_OK = qw($Var1 %Hashit &func3);
+ }
+ use vars @EXPORT_OK;
+
+ # non-exported package globals go here
+ use vars qw(@more $stuff);
+
+ # initalize package globals, first exported ones
+ $Var1 = '';
+ %Hashit = ();
+
+ # then the others (which are still accessible as $Some::Module::stuff)
+ $stuff = '';
+ @more = ();
+
+ # all file-scoped lexicals must be created before
+ # the functions below that use them.
+
+ # file-private lexicals go here
+ my $priv_var = '';
+ my %secret_hash = ();
+
+ # here's a file-private function as a closure,
+ # callable as &$priv_func; it cannot be prototyped.
+ my $priv_func = sub {
+ # stuff goes here.
+ };
+
+ # make all your functions, whether exported or not;
+ # remember to put something interesting in the {} stubs
+ sub func1 {} # no prototype
+ sub func2() {} # proto'd void
+ sub func3($$) {} # proto'd to 2 scalars
+
+ # this one isn't exported, but could be called!
+ sub func4(\%) {} # proto'd to 1 hash ref
+
+ END { } # module clean-up code here (global destructor)
Then go on to declare and use your variables in functions
without any qualifications.
-See L<Exporter> and the I<Perl Modules File> for details on
+See L<Exporter> and the I<Perl Modules File> for details on
mechanics and style issues in module creation.
Perl modules are included into your program by saying
instead of C<use>. With require you can get into this problem:
require Cwd; # make Cwd:: accessible
- $here = Cwd::getcwd();
+ $here = Cwd::getcwd();
- use Cwd; # import names from Cwd::
+ use Cwd; # import names from Cwd::
$here = getcwd();
require Cwd; # make Cwd:: accessible
the module. It is the responsibility of the F<.pm> file to load (or
arrange to autoload) any additional functionality. The POSIX module
happens to do both dynamic loading and autoloading, but the user can
-just say C<use POSIX> to get it all.
+say just C<use POSIX> to get it all.
For more information on writing extension modules, see L<perlxs>
and L<perlguts>.
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 (AKA documentation) may make other
+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.
=head1 THE PERL MODULE LIBRARY
-A number of modules are included the the Perl distribution. These are
-described below, and all end in F<.pm>. You may also discover files in
+A number of modules are included the Perl distribution. These are
+described below, and all end in F<.pm>. 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 module.) The B<pl2pm> file in the distribution may help in your
-conversion, but it's just a mechanical process, so is far from bullet proof.
+conversion, but it's just a mechanical process and therefore far from
+bulletproof.
=head2 Pragmatic Modules
They work somewhat like pragmas in that they tend to affect the compilation of
-your program, and thus will usually only work well when used within a
-C<use>, or C<no>. These are locally scoped, so an inner BLOCK
-may countermand any of these by saying
+your program, and thus will usually work well only when used within a
+C<use>, or C<no>. Most of these are locally scoped, so an inner BLOCK
+may countermand any of these by saying:
no integer;
no strict 'refs';
which lasts until the end of that BLOCK.
-The following programs are defined (and have their own documentation).
+Unlike the pragmas that effect the C<$^H> hints variable, the C<use
+vars> and C<use subs> declarations are not BLOCK-scoped. They 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 blib
+
+manipulate @INC at compile time to use MakeMaker's uninstalled version
+of a package
+
=item diagnostics
-Pragma to produce enhanced diagnostics
+force verbose warning diagnostics
=item integer
-Pragma to compute arithmetic in integer instead of double
+compute arithmetic in integer instead of double
=item less
-Pragma to request less of something from the compiler
+request less of something from the compiler
+
+=item lib
+
+manipulate @INC at compile time
+
+=item locale
+
+use or ignore current locale for builtin operations (see L<perllocale>)
+
+=item ops
+
+restrict named opcodes when compiling or running Perl code
=item overload
-Pragma for overloading operators
+overload basic Perl operations
=item sigtrap
-Pragma to enable stack backtrace on unexpected signals
+enable simple signal handling
=item strict
-Pragma to restrict unsafe constructs
+restrict unsafe constructs
=item subs
-Pragma to predeclare sub names
+predeclare sub names
+
+=item vmsish
+
+adopt certain VMS-specific behaviors
+
+=item vars
+
+predeclare global variable names
=back
benchmark running times of code
+=item CPAN
+
+interface to Comprehensive Perl Archive Network
+
+=item CPAN::FirstTime
+
+create a CPAN configuration file
+
+=item CPAN::Nox
+
+run CPAN while avoiding compiled extensions
+
=item Carp
warn of errors (from perspective of caller)
+=item Class::Struct
+
+declare struct-like datatypes
+
=item Config
-access Perl configuration option
+access Perl configuration information
=item Cwd
=item DB_File
-Perl access to Berkeley DB
+access to Berkeley DB
=item Devel::SelfStubber
generate stubs for a SelfLoading module
+=item DirHandle
+
+supply object methods for directory handles
+
=item DynaLoader
-Dynamically load C libraries into Perl code
+dynamically load C libraries into Perl code
=item English
=item Env
-perl module that imports environment variables
+import environment variables
=item Exporter
-provide inport/export controls for Perl modules
+implements default import method for modules
+
+=item ExtUtils::Embed
+
+utilities for embedding Perl in C/C++ applications
+
+=item ExtUtils::Install
+
+install files from here to there
=item ExtUtils::Liblist
determine libraries to use and how to use them
+=item ExtUtils::MM_OS2
+
+methods to override Unix behaviour in ExtUtils::MakeMaker
+
+=item ExtUtils::MM_Unix
+
+methods used by ExtUtils::MakeMaker
+
+=item ExtUtils::MM_VMS
+
+methods to override Unix behaviour in ExtUtils::MakeMaker
+
=item ExtUtils::MakeMaker
create an extension Makefile
make a bootstrap file for use by DynaLoader
-=item ExtUtils::Miniperl
+=item ExtUtils::Mksymlists
-!!!GOOD QUESTION!!!
+write linker options files for dynamic extension
+
+=item ExtUtils::testlib
+
+add blib/* directories to @INC
=item Fcntl
=item File::Basename
-parse file specifications
+split a pathname into pieces
=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::Find
traverse a file tree
+=item File::Path
+
+create or remove a series of directories
+
+=item File::stat
+
+by-name interface to Perl's builtin stat() functions
+
+=item FileCache
+
+keep more files open than the system permits
+
=item FileHandle
supply object methods for filehandles
-=item File::Path
+=item FindBin
-create or remove a series of directories
+locate directory of original perl script
+
+=item GDBM_File
+
+access to the gdbm library
=item Getopt::Long
-extended getopt processing
+extended processing of command line options
=item Getopt::Std
-Process single-character switches with switch clustering
+process single-character switches with switch clustering
=item I18N::Collate
compare 8-bit scalar data according to the current locale
+=item IO
+
+load various IO modules
+
+=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::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 IPC::Open2
-a process for both reading and writing
+open a process for both reading and writing
=item IPC::Open3
open a process for reading, writing, and error handling
+=item Math::BigFloat
+
+arbitrary length float math package
+
+=item Math::BigInt
+
+arbitrary size integer math package
+
+=item Math::Complex
+
+complex numbers and associated mathematical functions
+
+=item NDBM_File
+
+tied access to ndbm files
+
=item Net::Ping
-check a host for upness
+Hello, anybody home?
+
+=item Net::hostent
+
+by-name interface to Perl's builtin gethost*() functions
+
+=item Net::netent
+
+by-name interface to Perl's builtin getnet*() functions
+
+=item Net::protoent
+
+by-name interface to Perl's builtin getproto*() functions
+
+=item Net::servent
+
+by-name interface to Perl's builtin getserv*() functions
+
+=item Opcode
+
+disable named opcodes when compiling or running perl code
+
+=item Pod::Text
+
+convert POD data to formatted ASCII text
=item POSIX
-Perl interface to IEEE Std 1003.1
+interface to IEEE Standard 1003.1
+
+=item SDBM_File
+
+tied access to sdbm files
+
+=item Safe
+
+compile and execute code in restricted compartments
+
+=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 Safe
+=item Shell
-Creation controlled compartments in which perl code can be evaluated.
+run shell commands transparently within perl
=item Socket
load the C socket.h defines and structure manipulators
+=item Symbol
+
+manipulate Perl symbols and their names
+
+=item Sys::Hostname
+
+try every conceivable way to get hostname
+
+=item Sys::Syslog
+
+interface to the Unix syslog(3) calls
+
+=item Term::Cap
+
+termcap interface
+
+=item Term::Complete
+
+word completion module
+
+=item Term::ReadLine
+
+interface to various C<readline> packages
+
=item Test::Harness
run perl standard test scripts with statistics
=item Text::Abbrev
-rceate an abbreviation table from a list
+create an abbreviation table from a list
+
+=item Text::ParseWords
+
+parse text into an array of tokens
+
+=item Text::Soundex
+
+implementation of the Soundex Algorithm as described by Knuth
+
+=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 Tie::Hash
+
+base class definitions for tied hashes
+
+=item Tie::RefHash
+
+base class definitions for tied hashes with references as keys
+
+=item Tie::Scalar
+
+base class definitions for tied scalars
+
+=item Tie::SubstrHash
+
+fixed-table-size, fixed-key-length hashing
+
+=item Time::Local
+
+efficiently compute time from local and GMT time
+
+=item Time::gmtime
+
+by-name interface to Perl's builtin gmtime() function
+
+=item Time::localtime
+
+by-name interface to Perl's builtin localtime() function
+
+=item Time::tm
+
+internal object used by Time::gmtime and Time::localtime
+
+=item UNIVERSAL
+
+base class for ALL classes (blessed references)
+
+=item User::grent
+
+by-name interface to Perl's builtin getgr*() functions
+
+=item User::pwent
+
+by-name interface to Perl's builtin getpw*() functions
=back
=head2 Extension Modules
-Extension modules are written in C (or a mix of Perl and C) and get
+Extension modules are written in C (or a mix of Perl and C) and may be
+statically linked or in general are
dynamically loaded into Perl if and when you need them. Supported
extension modules include the Socket, Fcntl, and POSIX modules.
Many popular C extension modules do not come bundled (at least, not
-completely) due to their size, volatility, or simply lack of time for
+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 in
archie(1L), the Perl FAQ or Meta-FAQ, the WWW page, and even with their
=head1 CPAN
CPAN stands for the Comprehensive Perl Archive Network. This is a globally
-replicated collection of all known Perl materials, including hundreds
-of unbunded modules. Here are the major categories of modules:
+replicated collection of all known Perl materials, including hundreds
+of unbundled modules. Here are the major categories of modules:
=over
=item *
-Language Extensions and Documentation Tools
+Language Extensions and Documentation Tools
=item *
Development Support
File Names, File Systems and File Locking (see also File Handles)
=item *
-String Processing, Language Text Processing, Parsing and Searching
+String Processing, Language Text Processing, Parsing, and Searching
=item *
-Option, Argument, Parameter and Configuration File Processing
+Option, Argument, Parameter, and Configuration File Processing
=item *
Internationalization and Locale
=item *
-Authentication, Security and Encryption
+Authentication, Security, and Encryption
=item *
World Wide Web, HTML, HTTP, CGI, MIME
Archiving and Compression
=item *
-Images, Pixmap and Bitmap Manipulation, Drawing and Graphing
+Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing
=item *
Mail and Usenet News
=back
-Some of the reguster CPAN sites as of this writing include the following.
+The registered CPAN sites as of this writing include the following.
You should try to choose one close to you:
=over
=item *
-ftp://ftp.sterling.com/programming/languages/perl/
-
-=item *
-ftp://ftp.sedl.org/pub/mirrors/CPAN/
-
-=item *
-ftp://ftp.uoknor.edu/mirrors/CPAN/
-
-=item *
-ftp://ftp.delphi.com/pub/mirrors/packages/perl/CPAN/
-
-=item *
-ftp://uiarchive.cso.uiuc.edu/pub/lang/perl/CPAN/
-
-=item *
-ftp://ftp.cis.ufl.edu/pub/perl/CPAN/
+Africa
-=item *
-ftp://ftp.switch.ch/mirror/CPAN/
-
-=item *
-ftp://ftp.sunet.se/pub/lang/perl/CPAN/
-
-=item *
-ftp://ftp.ci.uminho.pt/pub/lang/perl/
-
-=item *
-ftp://ftp.cs.ruu.nl/pub/PERL/CPAN/
-
-=item *
-ftp://ftp.demon.co.uk/pub/mirrors/perl/CPAN/
-
-=item *
-ftp://ftp.rz.ruhr-uni-bochum.de/pub/programming/languages/perl/CPAN/
-
-=item *
-ftp://ftp.leo.org/pub/comp/programming/languages/perl/CPAN/
-
-=item *
-ftp://ftp.pasteur.fr/pub/computing/unix/perl/CPAN/
+ South Africa ftp://ftp.is.co.za/programming/perl/CPAN/
=item *
-ftp://ftp.ibp.fr/pub/perl/CPAN/
+Asia
-=item *
-ftp://ftp.funet.fi/pub/languages/perl/CPAN/
+ Hong Kong ftp://ftp.hkstar.com/pub/CPAN/
+ Japan ftp://ftp.jaist.ac.jp/pub/lang/perl/CPAN/
+ ftp://ftp.lab.kdd.co.jp/lang/perl/CPAN/
+ South Korea ftp://ftp.nuri.net/pub/CPAN/
+ Taiwan ftp://dongpo.math.ncu.edu.tw/perl/CPAN/
+ ftp://ftp.wownet.net/pub2/PERL/
=item *
-ftp://ftp.tekotago.ac.nz/pub/perl/CPAN/
+Australasia
-=item *
-ftp://ftp.mame.mu.oz.au/pub/perl/CPAN/
+ Australia ftp://ftp.netinfo.com.au/pub/perl/CPAN/
+ New Zealand ftp://ftp.tekotago.ac.nz/pub/perl/CPAN/
=item *
-ftp://coombs.anu.edu.au/pub/perl/
+Europe
+
+ Austria ftp://ftp.tuwien.ac.at/pub/languages/perl/CPAN/
+ Belgium ftp://ftp.kulnet.kuleuven.ac.be/pub/mirror/CPAN/
+ Czech Republic ftp://sunsite.mff.cuni.cz/Languages/Perl/CPAN/
+ Denmark ftp://sunsite.auc.dk/pub/languages/perl/CPAN/
+ Finland ftp://ftp.funet.fi/pub/languages/perl/CPAN/
+ France ftp://ftp.ibp.fr/pub/perl/CPAN/
+ ftp://ftp.pasteur.fr/pub/computing/unix/perl/CPAN/
+ Germany ftp://ftp.gmd.de/packages/CPAN/
+ ftp://ftp.leo.org/pub/comp/programming/languages/perl/CPAN/
+ ftp://ftp.mpi-sb.mpg.de/pub/perl/CPAN/
+ ftp://ftp.rz.ruhr-uni-bochum.de/pub/CPAN/
+ ftp://ftp.uni-erlangen.de/pub/source/Perl/CPAN/
+ ftp://ftp.uni-hamburg.de/pub/soft/lang/perl/CPAN/
+ Greece ftp://ftp.ntua.gr/pub/lang/perl/
+ Hungary ftp://ftp.kfki.hu/pub/packages/perl/CPAN/
+ Italy ftp://cis.utovrm.it/CPAN/
+ the Netherlands ftp://ftp.cs.ruu.nl/pub/PERL/CPAN/
+ ftp://ftp.EU.net/packages/cpan/
+ Norway ftp://ftp.uit.no/pub/languages/perl/cpan/
+ Poland ftp://ftp.pk.edu.pl/pub/lang/perl/CPAN/
+ ftp://sunsite.icm.edu.pl/pub/CPAN/
+ Portugal ftp://ftp.ci.uminho.pt/pub/lang/perl/
+ ftp://ftp.telepac.pt/pub/CPAN/
+ Russia ftp://ftp.sai.msu.su/pub/lang/perl/CPAN/
+ Slovenia ftp://ftp.arnes.si/software/perl/CPAN/
+ Spain ftp://ftp.etse.urv.es/pub/mirror/perl/
+ ftp://ftp.rediris.es/mirror/CPAN/
+ Sweden ftp://ftp.sunet.se/pub/lang/perl/CPAN/
+ UK ftp://ftp.demon.co.uk/pub/mirrors/perl/CPAN/
+ ftp://sunsite.doc.ic.ac.uk/packages/CPAN/
+ ftp://unix.hensa.ac.uk/mirrors/perl-CPAN/
=item *
-ftp://dongpo.math.ncu.edu.tw/perl/CPAN/
+North America
+
+ Ontario ftp://ftp.utilis.com/public/CPAN/
+ ftp://enterprise.ic.gc.ca/pub/perl/CPAN/
+ Manitoba ftp://theory.uwinnipeg.ca/pub/CPAN/
+ California ftp://ftp.digital.com/pub/plan/perl/CPAN/
+ ftp://ftp.cdrom.com/pub/perl/CPAN/
+ Colorado ftp://ftp.cs.colorado.edu/pub/perl/CPAN/
+ Florida ftp://ftp.cis.ufl.edu/pub/perl/CPAN/
+ Illinois ftp://uiarchive.uiuc.edu/pub/lang/perl/CPAN/
+ Massachusetts ftp://ftp.iguide.com/pub/mirrors/packages/perl/CPAN/
+ New York ftp://ftp.rge.com/pub/languages/perl/
+ North Carolina ftp://ftp.duke.edu/pub/perl/
+ Oklahoma ftp://ftp.ou.edu/mirrors/CPAN/
+ Oregon http://www.perl.org/CPAN/
+ ftp://ftp.orst.edu/pub/packages/CPAN/
+ Pennsylvania ftp://ftp.epix.net/pub/languages/perl/
+ Texas ftp://ftp.sedl.org/pub/mirrors/CPAN/
+ ftp://ftp.metronet.com/pub/perl/
=item *
-ftp://ftp.lab.kdd.co.jp/lang/perl/CPAN/
+South America
-=item *
-ftp://ftp.is.co.za/programming/perl/CPAN/
+ Chile ftp://sunsite.dcc.uchile.cl/pub/Lang/perl/CPAN/
=back
-For an up-to-date listing of CPAN sites,
-see http://www.perl.com/perl/ or ftp://ftp.perl.com/perl/ .
+For an up-to-date listing of CPAN sites,
+see F<http://www.perl.com/perl/CPAN> or F<ftp://ftp.perl.com/perl/>.
-=head1 Modules: Creation, Use and Abuse
+=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 5 implements a class using a package, but the presence of a
+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
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.:
+e.g.,:
- sub new {
+ 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 {
+ sub new {
my $self = shift;
my $class = ref($self) || $self;
return bless {}, $class;
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 hardwired
+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 $r-E<gt>Class::func() where using @ISA=qw(... Class ...) and
-$r-E<gt>func() would work (see perlbot man page for more details).
+Avoid C<$r-E<gt>Class::func()> where using C<@ISA=qw(... Class ...)> and
+C<$r-E<gt>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 which don't use them. Add test functions to
eval join('',<main::DATA>) || die $@ unless caller();
-Does your module pass the 'empty sub-class' test? If you say
-"@SUBCLASS::ISA = qw(YOURCLASS);" your applications should be able
+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: $obj = new YOURCLASS;
-into: $obj = new SUBCLASS; ?
+does your application still work if you change: C<$obj = new YOURCLASS;>
+into: C<$obj = new SUBCLASS;> ?
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 C<-w>. Try to C<use strict;> (or C<use strict qw(...);>).
+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 which need less strictness. Always use C<-w>. Always use C<-w>!
+of code which need less strictness. Always use B<-w>. Always use B<-w>!
Follow the guidelines in the perlstyle(1) manual.
=item Some simple style guidelines
$no_caps_here function scope my() or local() variables
Function and method names seem to work best as all lowercase.
-E.g., $obj-E<gt>as_string().
+e.g.,, C<$obj-E<gt>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.
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 $blessed_ref-E<gt>method)
+module using the ModuleName::item_name (or C<$blessed_ref-E<gt>method>)
syntax. By convention you can use a leading underscore on names to
-informally indicate that they are 'internal' and not for public use.
+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, since a method must have a name in the symbol
+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
=item Select a name for the module.
-This name should be as descriptive, accurate and complete as
+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 informally group or categorise a module.
-A module should have a very good reason not to have a nested name.
+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
those modules.
To be portable each component of a module name should be limited to
-11 characters. If it might be used on DOS then try to ensure each is
+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?
split out some of the sections into separate files: INSTALL,
Copying, ToDo etc.
+=over 4
+
=item Adding a Copyright Notice.
-How you choose to licence your work is a personal decision.
+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 License (see the files README, Copying and
+GPL and The Artistic Licence (see the files README, Copying, and
Artistic). 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 simply state something like:
+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
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 valid floating point
-number with at least two digits after the decimal (ie hundredths,
-e.g, $VERSION = "0.01"). Don't use a "1.3.2" style version.
+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 Exporter.pm in Perl5.001m or later for details.
It may be handy to add a function or method to retrieve the number.
distribution.
If possible you should place the module into a major ftp archive and
-include details of it's location in your announcement.
+include details of its location in your announcement.
Some notes about ftp archives: Please use a long descriptive file
name which includes the version number. Most incoming directories
http://franz.ww.tu-berlin.de/modulelist
-or upload to one of these sites:
+or upload to one of these sites:
ftp://franz.ww.tu-berlin.de/incoming
- ftp://ftp.cis.ufl.edu/incoming
+ ftp://ftp.cis.ufl.edu/incoming
-and notify upload@franz.ww.tu-berlin.de.
+and notify <F<upload@franz.ww.tu-berlin.de>>.
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
=back
+=back
+
=head2 Guidelines for Converting Perl 4 Library Scripts into Modules
=over 4
the application could invoked as:
perl -e 'use Module::Name; method(@ARGV)' ...
-or
- perl -mModule::Name ... (in perl5.002?)
+or
+ perl -mModule::Name ... (in perl5.002 or higher)
=back
-
projects / p5sagit/p5-mst-13.2.git / blobdiff