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1 | =head1 NAME |
2 | |
3 | perlmodlib - constructing new Perl modules and finding existing ones |
4 | |
5 | =head1 DESCRIPTION |
6 | |
7 | =head1 THE PERL MODULE LIBRARY |
8 | |
9 | A number of modules are included the Perl distribution. These are |
10 | described below, and all end in F<.pm>. You may also discover files in |
11 | the library directory that end in either F<.pl> or F<.ph>. These are old |
12 | libraries supplied so that old programs that use them still run. The |
13 | F<.pl> files will all eventually be converted into standard modules, and |
14 | the F<.ph> files made by B<h2ph> will probably end up as extension modules |
15 | made by B<h2xs>. (Some F<.ph> values may already be available through the |
16 | POSIX module.) The B<pl2pm> file in the distribution may help in your |
17 | conversion, but it's just a mechanical process and therefore far from |
18 | bulletproof. |
19 | |
20 | =head2 Pragmatic Modules |
21 | |
22 | They work somewhat like pragmas in that they tend to affect the compilation of |
23 | your program, and thus will usually work well only when used within a |
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24 | C<use>, or C<no>. Most of these are lexically scoped, so an inner BLOCK |
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25 | may countermand any of these by saying: |
26 | |
27 | no integer; |
28 | no strict 'refs'; |
29 | |
30 | which lasts until the end of that BLOCK. |
31 | |
32 | Unlike the pragmas that effect the C<$^H> hints variable, the C<use |
33 | vars> and C<use subs> declarations are not BLOCK-scoped. They allow |
34 | you to predeclare a variables or subroutines within a particular |
35 | I<file> rather than just a block. Such declarations are effective |
36 | for the entire file for which they were declared. You cannot rescind |
37 | them with C<no vars> or C<no subs>. |
38 | |
39 | The following pragmas are defined (and have their own documentation). |
40 | |
41 | =over 12 |
42 | |
43 | =item use autouse MODULE => qw(sub1 sub2 sub3) |
44 | |
45 | Defers C<require MODULE> until someone calls one of the specified |
46 | subroutines (which must be exported by MODULE). This pragma should be |
47 | used with caution, and only when necessary. |
48 | |
49 | =item blib |
50 | |
51 | manipulate @INC at compile time to use MakeMaker's uninstalled version |
52 | of a package |
53 | |
54 | =item diagnostics |
55 | |
56 | force verbose warning diagnostics |
57 | |
58 | =item integer |
59 | |
60 | compute arithmetic in integer instead of double |
61 | |
62 | =item less |
63 | |
64 | request less of something from the compiler |
65 | |
66 | =item lib |
67 | |
68 | manipulate @INC at compile time |
69 | |
70 | =item locale |
71 | |
72 | use or ignore current locale for builtin operations (see L<perllocale>) |
73 | |
74 | =item ops |
75 | |
76 | restrict named opcodes when compiling or running Perl code |
77 | |
78 | =item overload |
79 | |
80 | overload basic Perl operations |
81 | |
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82 | =item re |
83 | |
84 | alter behaviour of regular expressions |
85 | |
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86 | =item sigtrap |
87 | |
88 | enable simple signal handling |
89 | |
90 | =item strict |
91 | |
92 | restrict unsafe constructs |
93 | |
94 | =item subs |
95 | |
96 | predeclare sub names |
97 | |
98 | =item vmsish |
99 | |
100 | adopt certain VMS-specific behaviors |
101 | |
102 | =item vars |
103 | |
104 | predeclare global variable names |
105 | |
106 | =back |
107 | |
108 | =head2 Standard Modules |
109 | |
110 | Standard, bundled modules are all expected to behave in a well-defined |
111 | manner with respect to namespace pollution because they use the |
112 | Exporter module. See their own documentation for details. |
113 | |
114 | =over 12 |
115 | |
116 | =item AnyDBM_File |
117 | |
118 | provide framework for multiple DBMs |
119 | |
120 | =item AutoLoader |
121 | |
122 | load functions only on demand |
123 | |
124 | =item AutoSplit |
125 | |
126 | split a package for autoloading |
127 | |
128 | =item Benchmark |
129 | |
130 | benchmark running times of code |
131 | |
132 | =item CPAN |
133 | |
134 | interface to Comprehensive Perl Archive Network |
135 | |
136 | =item CPAN::FirstTime |
137 | |
138 | create a CPAN configuration file |
139 | |
140 | =item CPAN::Nox |
141 | |
142 | run CPAN while avoiding compiled extensions |
143 | |
144 | =item Carp |
145 | |
146 | warn of errors (from perspective of caller) |
147 | |
148 | =item Class::Struct |
149 | |
150 | declare struct-like datatypes |
151 | |
152 | =item Config |
153 | |
154 | access Perl configuration information |
155 | |
156 | =item Cwd |
157 | |
158 | get pathname of current working directory |
159 | |
160 | =item DB_File |
161 | |
162 | access to Berkeley DB |
163 | |
164 | =item Devel::SelfStubber |
165 | |
166 | generate stubs for a SelfLoading module |
167 | |
168 | =item DirHandle |
169 | |
170 | supply object methods for directory handles |
171 | |
172 | =item DynaLoader |
173 | |
174 | dynamically load C libraries into Perl code |
175 | |
176 | =item English |
177 | |
178 | use nice English (or awk) names for ugly punctuation variables |
179 | |
180 | =item Env |
181 | |
182 | import environment variables |
183 | |
184 | =item Exporter |
185 | |
186 | implements default import method for modules |
187 | |
188 | =item ExtUtils::Embed |
189 | |
190 | utilities for embedding Perl in C/C++ applications |
191 | |
192 | =item ExtUtils::Install |
193 | |
194 | install files from here to there |
195 | |
196 | =item ExtUtils::Liblist |
197 | |
198 | determine libraries to use and how to use them |
199 | |
200 | =item ExtUtils::MM_OS2 |
201 | |
202 | methods to override Unix behaviour in ExtUtils::MakeMaker |
203 | |
204 | =item ExtUtils::MM_Unix |
205 | |
206 | methods used by ExtUtils::MakeMaker |
207 | |
208 | =item ExtUtils::MM_VMS |
209 | |
210 | methods to override Unix behaviour in ExtUtils::MakeMaker |
211 | |
212 | =item ExtUtils::MakeMaker |
213 | |
214 | create an extension Makefile |
215 | |
216 | =item ExtUtils::Manifest |
217 | |
218 | utilities to write and check a MANIFEST file |
219 | |
220 | =item ExtUtils::Mkbootstrap |
221 | |
222 | make a bootstrap file for use by DynaLoader |
223 | |
224 | =item ExtUtils::Mksymlists |
225 | |
226 | write linker options files for dynamic extension |
227 | |
228 | =item ExtUtils::testlib |
229 | |
230 | add blib/* directories to @INC |
231 | |
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232 | =item Fatal |
233 | |
234 | make errors in builtins or Perl functions fatal |
235 | |
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236 | =item Fcntl |
237 | |
238 | load the C Fcntl.h defines |
239 | |
240 | =item File::Basename |
241 | |
242 | split a pathname into pieces |
243 | |
244 | =item File::CheckTree |
245 | |
246 | run many filetest checks on a tree |
247 | |
248 | =item File::Compare |
249 | |
250 | compare files or filehandles |
251 | |
252 | =item File::Copy |
253 | |
254 | copy files or filehandles |
255 | |
256 | =item File::Find |
257 | |
258 | traverse a file tree |
259 | |
260 | =item File::Path |
261 | |
262 | create or remove a series of directories |
263 | |
264 | =item File::stat |
265 | |
266 | by-name interface to Perl's builtin stat() functions |
267 | |
268 | =item FileCache |
269 | |
270 | keep more files open than the system permits |
271 | |
272 | =item FileHandle |
273 | |
274 | supply object methods for filehandles |
275 | |
276 | =item FindBin |
277 | |
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278 | locate directory of original Perl script |
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279 | |
280 | =item GDBM_File |
281 | |
282 | access to the gdbm library |
283 | |
284 | =item Getopt::Long |
285 | |
286 | extended processing of command line options |
287 | |
288 | =item Getopt::Std |
289 | |
290 | process single-character switches with switch clustering |
291 | |
292 | =item I18N::Collate |
293 | |
294 | compare 8-bit scalar data according to the current locale |
295 | |
296 | =item IO |
297 | |
298 | load various IO modules |
299 | |
300 | =item IO::File |
301 | |
302 | supply object methods for filehandles |
303 | |
304 | =item IO::Handle |
305 | |
306 | supply object methods for I/O handles |
307 | |
308 | =item IO::Pipe |
309 | |
310 | supply object methods for pipes |
311 | |
312 | =item IO::Seekable |
313 | |
314 | supply seek based methods for I/O objects |
315 | |
316 | =item IO::Select |
317 | |
318 | OO interface to the select system call |
319 | |
320 | =item IO::Socket |
321 | |
322 | object interface to socket communications |
323 | |
324 | =item IPC::Open2 |
325 | |
326 | open a process for both reading and writing |
327 | |
328 | =item IPC::Open3 |
329 | |
330 | open a process for reading, writing, and error handling |
331 | |
332 | =item Math::BigFloat |
333 | |
334 | arbitrary length float math package |
335 | |
336 | =item Math::BigInt |
337 | |
338 | arbitrary size integer math package |
339 | |
340 | =item Math::Complex |
341 | |
342 | complex numbers and associated mathematical functions |
343 | |
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344 | =item Math::Trig |
345 | |
346 | simple interface to parts of Math::Complex for those who |
347 | need trigonometric functions only for real numbers |
348 | |
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349 | =item NDBM_File |
350 | |
351 | tied access to ndbm files |
352 | |
353 | =item Net::Ping |
354 | |
355 | Hello, anybody home? |
356 | |
357 | =item Net::hostent |
358 | |
359 | by-name interface to Perl's builtin gethost*() functions |
360 | |
361 | =item Net::netent |
362 | |
363 | by-name interface to Perl's builtin getnet*() functions |
364 | |
365 | =item Net::protoent |
366 | |
367 | by-name interface to Perl's builtin getproto*() functions |
368 | |
369 | =item Net::servent |
370 | |
371 | by-name interface to Perl's builtin getserv*() functions |
372 | |
373 | =item Opcode |
374 | |
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375 | disable named opcodes when compiling or running Perl code |
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376 | |
377 | =item Pod::Text |
378 | |
379 | convert POD data to formatted ASCII text |
380 | |
381 | =item POSIX |
382 | |
383 | interface to IEEE Standard 1003.1 |
384 | |
385 | =item SDBM_File |
386 | |
387 | tied access to sdbm files |
388 | |
389 | =item Safe |
390 | |
391 | compile and execute code in restricted compartments |
392 | |
393 | =item Search::Dict |
394 | |
395 | search for key in dictionary file |
396 | |
397 | =item SelectSaver |
398 | |
399 | save and restore selected file handle |
400 | |
401 | =item SelfLoader |
402 | |
403 | load functions only on demand |
404 | |
405 | =item Shell |
406 | |
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407 | run shell commands transparently within Perl |
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408 | |
409 | =item Socket |
410 | |
411 | load the C socket.h defines and structure manipulators |
412 | |
413 | =item Symbol |
414 | |
415 | manipulate Perl symbols and their names |
416 | |
417 | =item Sys::Hostname |
418 | |
419 | try every conceivable way to get hostname |
420 | |
421 | =item Sys::Syslog |
422 | |
423 | interface to the Unix syslog(3) calls |
424 | |
425 | =item Term::Cap |
426 | |
427 | termcap interface |
428 | |
429 | =item Term::Complete |
430 | |
431 | word completion module |
432 | |
433 | =item Term::ReadLine |
434 | |
435 | interface to various C<readline> packages |
436 | |
437 | =item Test::Harness |
438 | |
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439 | run Perl standard test scripts with statistics |
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440 | |
441 | =item Text::Abbrev |
442 | |
443 | create an abbreviation table from a list |
444 | |
445 | =item Text::ParseWords |
446 | |
447 | parse text into an array of tokens |
448 | |
449 | =item Text::Soundex |
450 | |
451 | implementation of the Soundex Algorithm as described by Knuth |
452 | |
453 | =item Text::Tabs |
454 | |
455 | expand and unexpand tabs per the Unix expand(1) and unexpand(1) |
456 | |
457 | =item Text::Wrap |
458 | |
459 | line wrapping to form simple paragraphs |
460 | |
461 | =item Tie::Hash |
462 | |
463 | base class definitions for tied hashes |
464 | |
465 | =item Tie::RefHash |
466 | |
467 | base class definitions for tied hashes with references as keys |
468 | |
469 | =item Tie::Scalar |
470 | |
471 | base class definitions for tied scalars |
472 | |
473 | =item Tie::SubstrHash |
474 | |
475 | fixed-table-size, fixed-key-length hashing |
476 | |
477 | =item Time::Local |
478 | |
479 | efficiently compute time from local and GMT time |
480 | |
481 | =item Time::gmtime |
482 | |
483 | by-name interface to Perl's builtin gmtime() function |
484 | |
485 | =item Time::localtime |
486 | |
487 | by-name interface to Perl's builtin localtime() function |
488 | |
489 | =item Time::tm |
490 | |
491 | internal object used by Time::gmtime and Time::localtime |
492 | |
493 | =item UNIVERSAL |
494 | |
495 | base class for ALL classes (blessed references) |
496 | |
497 | =item User::grent |
498 | |
499 | by-name interface to Perl's builtin getgr*() functions |
500 | |
501 | =item User::pwent |
502 | |
503 | by-name interface to Perl's builtin getpw*() functions |
504 | |
505 | =back |
506 | |
507 | To find out I<all> the modules installed on your system, including |
508 | those without documentation or outside the standard release, do this: |
509 | |
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510 | % find `perl -e 'print "@INC"'` -name '*.pm' -print |
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511 | |
512 | They should all have their own documentation installed and accessible via |
513 | your system man(1) command. If that fails, try the I<perldoc> program. |
514 | |
515 | =head2 Extension Modules |
516 | |
517 | Extension modules are written in C (or a mix of Perl and C) and may be |
518 | statically linked or in general are |
519 | dynamically loaded into Perl if and when you need them. Supported |
520 | extension modules include the Socket, Fcntl, and POSIX modules. |
521 | |
522 | Many popular C extension modules do not come bundled (at least, not |
523 | completely) due to their sizes, volatility, or simply lack of time for |
524 | adequate testing and configuration across the multitude of platforms on |
525 | which Perl was beta-tested. You are encouraged to look for them in |
526 | archie(1L), the Perl FAQ or Meta-FAQ, the WWW page, and even with their |
527 | authors before randomly posting asking for their present condition and |
528 | disposition. |
529 | |
530 | =head1 CPAN |
531 | |
532 | CPAN stands for the Comprehensive Perl Archive Network. This is a globally |
533 | replicated collection of all known Perl materials, including hundreds |
534 | of unbundled modules. Here are the major categories of modules: |
535 | |
536 | =over |
537 | |
538 | =item * |
539 | Language Extensions and Documentation Tools |
540 | |
541 | =item * |
542 | Development Support |
543 | |
544 | =item * |
545 | Operating System Interfaces |
546 | |
547 | =item * |
548 | Networking, Device Control (modems) and InterProcess Communication |
549 | |
550 | =item * |
551 | Data Types and Data Type Utilities |
552 | |
553 | =item * |
554 | Database Interfaces |
555 | |
556 | =item * |
557 | User Interfaces |
558 | |
559 | =item * |
560 | Interfaces to / Emulations of Other Programming Languages |
561 | |
562 | =item * |
563 | File Names, File Systems and File Locking (see also File Handles) |
564 | |
565 | =item * |
566 | String Processing, Language Text Processing, Parsing, and Searching |
567 | |
568 | =item * |
569 | Option, Argument, Parameter, and Configuration File Processing |
570 | |
571 | =item * |
572 | Internationalization and Locale |
573 | |
574 | =item * |
575 | Authentication, Security, and Encryption |
576 | |
577 | =item * |
578 | World Wide Web, HTML, HTTP, CGI, MIME |
579 | |
580 | =item * |
581 | Server and Daemon Utilities |
582 | |
583 | =item * |
584 | Archiving and Compression |
585 | |
586 | =item * |
587 | Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing |
588 | |
589 | =item * |
590 | Mail and Usenet News |
591 | |
592 | =item * |
593 | Control Flow Utilities (callbacks and exceptions etc) |
594 | |
595 | =item * |
596 | File Handle and Input/Output Stream Utilities |
597 | |
598 | =item * |
599 | Miscellaneous Modules |
600 | |
601 | =back |
602 | |
603 | The registered CPAN sites as of this writing include the following. |
604 | You should try to choose one close to you: |
605 | |
606 | =over |
607 | |
608 | =item * |
609 | Africa |
610 | |
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611 | South Africa ftp://ftp.is.co.za/programming/perl/CPAN/ |
612 | ftp://ftpza.co.za/pub/mirrors/cpan/ |
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613 | |
614 | =item * |
615 | Asia |
616 | |
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617 | Armenia ftp://sunsite.aua.am/pub/CPAN/ |
618 | China ftp://freesoft.cei.gov.cn/pub/languages/perl/CPAN/ |
619 | Hong Kong ftp://ftp.hkstar.com/pub/CPAN/ |
620 | Israel ftp://bioinfo.weizmann.ac.il/pub/software/perl/CPAN/ |
621 | Japan ftp://ftp.dti.ad.jp/pub/lang/CPAN/ |
622 | ftp://ftp.jaist.ac.jp/pub/lang/perl/CPAN/ |
623 | ftp://ftp.lab.kdd.co.jp/lang/perl/CPAN/ |
624 | ftp://ftp.meisei-u.ac.jp/pub/CPAN/ |
625 | ftp://mirror.nucba.ac.jp/mirror/Perl/ |
626 | Singapore ftp://ftp.nus.edu.sg/pub/unix/perl/CPAN/ |
627 | South Korea ftp://ftp.bora.net/pub/CPAN/ |
628 | ftp://ftp.nuri.net/pub/CPAN/ |
629 | Taiwan ftp://ftp.wownet.net/pub2/PERL/ |
630 | ftp://ftp1.sinica.edu.tw/pub1/perl/CPAN/ |
631 | Thailand ftp://ftp.cs.riubon.ac.th/pub/mirrors/CPAN/ |
632 | ftp://ftp.nectec.or.th/pub/mirrors/CPAN/ |
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633 | |
634 | =item * |
635 | Australasia |
636 | |
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637 | Australia ftp://cpan.topend.com.au/pub/CPAN/ |
638 | ftp://ftp.labyrinth.net.au/pub/perl/CPAN/ |
639 | ftp://ftp.sage-au.org.au/pub/compilers/perl/CPAN/ |
640 | ftp://mirror.aarnet.edu.au/pub/perl/CPAN/ |
641 | New Zealand ftp://ftp.auckland.ac.nz/pub/perl/CPAN/ |
642 | ftp://sunsite.net.nz/pub/languages/perl/CPAN/ |
643 | |
644 | =item * |
645 | Central America |
646 | |
647 | Costa Rica ftp://ftp.ucr.ac.cr/pub/Unix/CPAN/ |
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648 | |
649 | =item * |
650 | Europe |
651 | |
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652 | Austria ftp://ftp.tuwien.ac.at/pub/languages/perl/CPAN/ |
653 | Belgium ftp://ftp.kulnet.kuleuven.ac.be/pub/mirror/CPAN/ |
654 | Bulgaria ftp://ftp.ntrl.net/pub/mirrors/CPAN/ |
655 | Croatia ftp://ftp.linux.hr/pub/CPAN/ |
656 | Czech Republic ftp://ftp.fi.muni.cz/pub/perl/ |
657 | ftp://sunsite.mff.cuni.cz/Languages/Perl/CPAN/ |
658 | Denmark ftp://sunsite.auc.dk/pub/languages/perl/CPAN/ |
659 | Estonia ftp://ftp.ut.ee/pub/languages/perl/CPAN/ |
660 | Finland ftp://ftp.funet.fi/pub/languages/perl/CPAN/ |
661 | France ftp://ftp.lip6.fr/pub/perl/CPAN/ |
662 | ftp://ftp.oleane.net/pub/mirrors/CPAN/ |
663 | ftp://ftp.pasteur.fr/pub/computing/CPAN/ |
664 | Germany ftp://ftp.archive.de.uu.net/pub/CPAN/ |
665 | ftp://ftp.gmd.de/packages/CPAN/ |
666 | ftp://ftp.gwdg.de/pub/languages/perl/CPAN/ |
667 | ftp://ftp.leo.org/pub/comp/programming/languages/script/perl/CPAN/ |
668 | ftp://ftp.mpi-sb.mpg.de/pub/perl/CPAN/ |
669 | ftp://ftp.rz.ruhr-uni-bochum.de/pub/CPAN/ |
670 | ftp://ftp.uni-erlangen.de/pub/source/CPAN/ |
671 | ftp://ftp.uni-hamburg.de/pub/soft/lang/perl/CPAN/ |
672 | Greece ftp://ftp.ntua.gr/pub/lang/perl/ |
673 | Hungary ftp://ftp.kfki.hu/pub/packages/perl/CPAN/ |
674 | Ireland ftp://sunsite.compapp.dcu.ie/pub/perl/ |
675 | Italy ftp://cis.uniRoma2.it/CPAN/ |
676 | ftp://ftp.flashnet.it/pub/CPAN/ |
677 | ftp://ftp.unipi.it/pub/mirror/perl/CPAN/ |
678 | Netherlands ftp://ftp.cs.uu.nl/mirror/CPAN/ |
679 | ftp://ftp.nluug.nl/pub/languages/perl/CPAN/ |
680 | Norway ftp://ftp.uit.no/pub/languages/perl/cpan/ |
681 | ftp://sunsite.uio.no/pub/languages/perl/CPAN/ |
682 | Poland ftp://ftp.man.szczecin.pl/pub/perl/CPAN/ |
683 | ftp://ftp.man.torun.pl/pub/doc/CPAN/ |
684 | ftp://ftp.pk.edu.pl/pub/lang/perl/CPAN/ |
685 | ftp://sunsite.icm.edu.pl/pub/CPAN/ |
686 | Portugal ftp://ftp.ci.uminho.pt/pub/mirrors/cpan/ |
687 | ftp://ftp.ua.pt/pub/CPAN/ |
688 | Romania ftp://ftp.dntis.ro/pub/mirrors/perl-cpan/ |
689 | ftp://ftp.dnttm.ro/pub/CPAN/ |
690 | Russia ftp://cpan.npi.msu.su/CPAN/ |
691 | ftp://ftp.sai.msu.su/pub/lang/perl/CPAN/ |
692 | Slovakia ftp://ftp.entry.sk/pub/languages/perl/CPAN/ |
693 | Slovenia ftp://ftp.arnes.si/software/perl/CPAN/ |
694 | Spain ftp://ftp.etse.urv.es/pub/perl/ |
695 | ftp://ftp.rediris.es/mirror/CPAN/ |
696 | Sweden ftp://ftp.sunet.se/pub/lang/perl/CPAN/ |
697 | Switzerland ftp://sunsite.cnlab-switch.ch/mirror/CPAN/ |
698 | Turkey ftp://sunsite.bilkent.edu.tr/pub/languages/CPAN/ |
699 | United Kingdom ftp://ftp.demon.co.uk/pub/mirrors/perl/CPAN/ |
700 | ftp://ftp.flirble.org/pub/languages/perl/CPAN/ |
701 | ftp://ftp.plig.org/pub/CPAN/ |
702 | ftp://sunsite.doc.ic.ac.uk/packages/CPAN/ |
703 | ftp://unix.hensa.ac.uk/mirrors/perl-CPAN/ |
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704 | |
705 | =item * |
706 | North America |
707 | |
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708 | Alberta ftp://sunsite.ualberta.ca/pub/Mirror/CPAN/ |
709 | California ftp://ftp.cdrom.com/pub/perl/CPAN/ |
710 | ftp://ftp.digital.com/pub/plan/perl/CPAN/ |
711 | Colorado ftp://ftp.cs.colorado.edu/pub/perl/CPAN/ |
712 | Florida ftp://ftp.cise.ufl.edu/pub/perl/CPAN/ |
713 | Illinois ftp://uiarchive.uiuc.edu/pub/lang/perl/CPAN/ |
714 | Indiana ftp://csociety-ftp.ecn.purdue.edu/pub/CPAN/ |
715 | ftp://ftp.uwsg.indiana.edu/pub/perl/CPAN/ |
716 | Manitoba ftp://theory.uwinnipeg.ca/pub/CPAN/ |
717 | Massachusetts ftp://ftp.ccs.neu.edu/net/mirrors/ftp.funet.fi/pub/languages/perl/CPAN/ |
718 | ftp://ftp.iguide.com/pub/mirrors/packages/perl/CPAN/ |
719 | Mexico D.F. ftp://ftp.msg.com.mx/pub/CPAN/ |
720 | New York ftp://ftp.rge.com/pub/languages/perl/ |
721 | North Carolina ftp://ftp.duke.edu/pub/perl/ |
722 | Oklahoma ftp://ftp.ou.edu/mirrors/CPAN/ |
723 | Ontario ftp://ftp.crc.ca/pub/packages/perl/CPAN/ |
724 | Oregon ftp://ftp.orst.edu/pub/packages/CPAN/ |
725 | Pennsylvania ftp://ftp.epix.net/pub/languages/perl/ |
726 | Texas ftp://ftp.sedl.org/pub/mirrors/CPAN/ |
727 | Utah ftp://mirror.xmission.com/CPAN/ |
728 | Virginia ftp://ftp.perl.org/pub/perl/CPAN/ |
729 | ftp://ruff.cs.jmu.edu/pub/CPAN/ |
730 | Washington ftp://ftp.spu.edu/pub/CPAN/ |
f102b883 |
731 | |
732 | =item * |
733 | South America |
734 | |
be94a901 |
735 | Brazil ftp://cpan.if.usp.br/pub/mirror/CPAN/ |
736 | Chile ftp://ftp.ing.puc.cl/pub/unix/perl/CPAN/ |
737 | ftp://sunsite.dcc.uchile.cl/pub/Lang/perl/CPAN/ |
f102b883 |
738 | |
739 | =back |
740 | |
741 | For an up-to-date listing of CPAN sites, |
742 | see F<http://www.perl.com/perl/CPAN> or F<ftp://ftp.perl.com/perl/>. |
743 | |
744 | =head1 Modules: Creation, Use, and Abuse |
745 | |
746 | (The following section is borrowed directly from Tim Bunce's modules |
747 | file, available at your nearest CPAN site.) |
748 | |
749 | Perl implements a class using a package, but the presence of a |
750 | package doesn't imply the presence of a class. A package is just a |
751 | namespace. A class is a package that provides subroutines that can be |
752 | used as methods. A method is just a subroutine that expects, as its |
753 | first argument, either the name of a package (for "static" methods), |
754 | or a reference to something (for "virtual" methods). |
755 | |
756 | A module is a file that (by convention) provides a class of the same |
757 | name (sans the .pm), plus an import method in that class that can be |
758 | called to fetch exported symbols. This module may implement some of |
759 | its methods by loading dynamic C or C++ objects, but that should be |
760 | totally transparent to the user of the module. Likewise, the module |
761 | might set up an AUTOLOAD function to slurp in subroutine definitions on |
762 | demand, but this is also transparent. Only the F<.pm> file is required to |
763 | exist. See L<perlsub>, L<perltoot>, and L<AutoLoader> for details about |
764 | the AUTOLOAD mechanism. |
765 | |
766 | =head2 Guidelines for Module Creation |
767 | |
768 | =over 4 |
769 | |
770 | =item Do similar modules already exist in some form? |
771 | |
772 | If so, please try to reuse the existing modules either in whole or |
773 | by inheriting useful features into a new class. If this is not |
774 | practical try to get together with the module authors to work on |
775 | extending or enhancing the functionality of the existing modules. |
776 | A perfect example is the plethora of packages in perl4 for dealing |
777 | with command line options. |
778 | |
779 | If you are writing a module to expand an already existing set of |
780 | modules, please coordinate with the author of the package. It |
781 | helps if you follow the same naming scheme and module interaction |
782 | scheme as the original author. |
783 | |
784 | =item Try to design the new module to be easy to extend and reuse. |
785 | |
786 | Use blessed references. Use the two argument form of bless to bless |
787 | into the class name given as the first parameter of the constructor, |
788 | e.g.,: |
789 | |
790 | sub new { |
791 | my $class = shift; |
792 | return bless {}, $class; |
793 | } |
794 | |
795 | or even this if you'd like it to be used as either a static |
796 | or a virtual method. |
797 | |
798 | sub new { |
799 | my $self = shift; |
800 | my $class = ref($self) || $self; |
801 | return bless {}, $class; |
802 | } |
803 | |
804 | Pass arrays as references so more parameters can be added later |
805 | (it's also faster). Convert functions into methods where |
806 | appropriate. Split large methods into smaller more flexible ones. |
807 | Inherit methods from other modules if appropriate. |
808 | |
809 | Avoid class name tests like: C<die "Invalid" unless ref $ref eq 'FOO'>. |
810 | Generally you can delete the "C<eq 'FOO'>" part with no harm at all. |
811 | Let the objects look after themselves! Generally, avoid hard-wired |
812 | class names as far as possible. |
813 | |
814 | Avoid C<$r-E<gt>Class::func()> where using C<@ISA=qw(... Class ...)> and |
815 | C<$r-E<gt>func()> would work (see L<perlbot> for more details). |
816 | |
817 | Use autosplit so little used or newly added functions won't be a |
5a964f20 |
818 | burden to programs that don't use them. Add test functions to |
f102b883 |
819 | the module after __END__ either using AutoSplit or by saying: |
820 | |
821 | eval join('',<main::DATA>) || die $@ unless caller(); |
822 | |
823 | Does your module pass the 'empty subclass' test? If you say |
824 | "C<@SUBCLASS::ISA = qw(YOURCLASS);>" your applications should be able |
825 | to use SUBCLASS in exactly the same way as YOURCLASS. For example, |
826 | does your application still work if you change: C<$obj = new YOURCLASS;> |
827 | into: C<$obj = new SUBCLASS;> ? |
828 | |
829 | Avoid keeping any state information in your packages. It makes it |
830 | difficult for multiple other packages to use yours. Keep state |
831 | information in objects. |
832 | |
833 | Always use B<-w>. Try to C<use strict;> (or C<use strict qw(...);>). |
834 | Remember that you can add C<no strict qw(...);> to individual blocks |
5a964f20 |
835 | of code that need less strictness. Always use B<-w>. Always use B<-w>! |
f102b883 |
836 | Follow the guidelines in the perlstyle(1) manual. |
837 | |
838 | =item Some simple style guidelines |
839 | |
5a964f20 |
840 | The perlstyle manual supplied with Perl has many helpful points. |
f102b883 |
841 | |
842 | Coding style is a matter of personal taste. Many people evolve their |
843 | style over several years as they learn what helps them write and |
844 | maintain good code. Here's one set of assorted suggestions that |
845 | seem to be widely used by experienced developers: |
846 | |
847 | Use underscores to separate words. It is generally easier to read |
848 | $var_names_like_this than $VarNamesLikeThis, especially for |
849 | non-native speakers of English. It's also a simple rule that works |
850 | consistently with VAR_NAMES_LIKE_THIS. |
851 | |
852 | Package/Module names are an exception to this rule. Perl informally |
853 | reserves lowercase module names for 'pragma' modules like integer |
854 | and strict. Other modules normally begin with a capital letter and |
855 | use mixed case with no underscores (need to be short and portable). |
856 | |
857 | You may find it helpful to use letter case to indicate the scope |
858 | or nature of a variable. For example: |
859 | |
5a964f20 |
860 | $ALL_CAPS_HERE constants only (beware clashes with Perl vars) |
f102b883 |
861 | $Some_Caps_Here package-wide global/static |
862 | $no_caps_here function scope my() or local() variables |
863 | |
864 | Function and method names seem to work best as all lowercase. |
865 | e.g., C<$obj-E<gt>as_string()>. |
866 | |
867 | You can use a leading underscore to indicate that a variable or |
868 | function should not be used outside the package that defined it. |
869 | |
870 | =item Select what to export. |
871 | |
872 | Do NOT export method names! |
873 | |
874 | Do NOT export anything else by default without a good reason! |
875 | |
876 | Exports pollute the namespace of the module user. If you must |
877 | export try to use @EXPORT_OK in preference to @EXPORT and avoid |
878 | short or common names to reduce the risk of name clashes. |
879 | |
880 | Generally anything not exported is still accessible from outside the |
881 | module using the ModuleName::item_name (or C<$blessed_ref-E<gt>method>) |
882 | syntax. By convention you can use a leading underscore on names to |
883 | indicate informally that they are 'internal' and not for public use. |
884 | |
885 | (It is actually possible to get private functions by saying: |
886 | C<my $subref = sub { ... }; &$subref;>. But there's no way to call that |
887 | directly as a method, because a method must have a name in the symbol |
888 | table.) |
889 | |
890 | As a general rule, if the module is trying to be object oriented |
891 | then export nothing. If it's just a collection of functions then |
892 | @EXPORT_OK anything but use @EXPORT with caution. |
893 | |
894 | =item Select a name for the module. |
895 | |
896 | This name should be as descriptive, accurate, and complete as |
897 | possible. Avoid any risk of ambiguity. Always try to use two or |
898 | more whole words. Generally the name should reflect what is special |
899 | about what the module does rather than how it does it. Please use |
900 | nested module names to group informally or categorize a module. |
901 | There should be a very good reason for a module not to have a nested name. |
902 | Module names should begin with a capital letter. |
903 | |
904 | Having 57 modules all called Sort will not make life easy for anyone |
905 | (though having 23 called Sort::Quick is only marginally better :-). |
906 | Imagine someone trying to install your module alongside many others. |
907 | If in any doubt ask for suggestions in comp.lang.perl.misc. |
908 | |
909 | If you are developing a suite of related modules/classes it's good |
910 | practice to use nested classes with a common prefix as this will |
911 | avoid namespace clashes. For example: Xyz::Control, Xyz::View, |
912 | Xyz::Model etc. Use the modules in this list as a naming guide. |
913 | |
914 | If adding a new module to a set, follow the original author's |
915 | standards for naming modules and the interface to methods in |
916 | those modules. |
917 | |
918 | To be portable each component of a module name should be limited to |
919 | 11 characters. If it might be used on MS-DOS then try to ensure each is |
920 | unique in the first 8 characters. Nested modules make this easier. |
921 | |
922 | =item Have you got it right? |
923 | |
924 | How do you know that you've made the right decisions? Have you |
925 | picked an interface design that will cause problems later? Have |
926 | you picked the most appropriate name? Do you have any questions? |
927 | |
928 | The best way to know for sure, and pick up many helpful suggestions, |
929 | is to ask someone who knows. Comp.lang.perl.misc is read by just about |
930 | all the people who develop modules and it's the best place to ask. |
931 | |
932 | All you need to do is post a short summary of the module, its |
933 | purpose and interfaces. A few lines on each of the main methods is |
934 | probably enough. (If you post the whole module it might be ignored |
935 | by busy people - generally the very people you want to read it!) |
936 | |
937 | Don't worry about posting if you can't say when the module will be |
938 | ready - just say so in the message. It might be worth inviting |
939 | others to help you, they may be able to complete it for you! |
940 | |
941 | =item README and other Additional Files. |
942 | |
943 | It's well known that software developers usually fully document the |
944 | software they write. If, however, the world is in urgent need of |
945 | your software and there is not enough time to write the full |
946 | documentation please at least provide a README file containing: |
947 | |
948 | =over 10 |
949 | |
950 | =item * |
951 | A description of the module/package/extension etc. |
952 | |
953 | =item * |
954 | A copyright notice - see below. |
955 | |
956 | =item * |
957 | Prerequisites - what else you may need to have. |
958 | |
959 | =item * |
960 | How to build it - possible changes to Makefile.PL etc. |
961 | |
962 | =item * |
963 | How to install it. |
964 | |
965 | =item * |
966 | Recent changes in this release, especially incompatibilities |
967 | |
968 | =item * |
969 | Changes / enhancements you plan to make in the future. |
970 | |
971 | =back |
972 | |
973 | If the README file seems to be getting too large you may wish to |
974 | split out some of the sections into separate files: INSTALL, |
975 | Copying, ToDo etc. |
976 | |
977 | =over 4 |
978 | |
979 | =item Adding a Copyright Notice. |
980 | |
981 | How you choose to license your work is a personal decision. |
982 | The general mechanism is to assert your Copyright and then make |
983 | a declaration of how others may copy/use/modify your work. |
984 | |
985 | Perl, for example, is supplied with two types of licence: The GNU |
986 | GPL and The Artistic Licence (see the files README, Copying, and |
987 | Artistic). Larry has good reasons for NOT just using the GNU GPL. |
988 | |
989 | My personal recommendation, out of respect for Larry, Perl, and the |
5a964f20 |
990 | Perl community at large is to state something simply like: |
f102b883 |
991 | |
992 | Copyright (c) 1995 Your Name. All rights reserved. |
993 | This program is free software; you can redistribute it and/or |
994 | modify it under the same terms as Perl itself. |
995 | |
996 | This statement should at least appear in the README file. You may |
997 | also wish to include it in a Copying file and your source files. |
998 | Remember to include the other words in addition to the Copyright. |
999 | |
1000 | =item Give the module a version/issue/release number. |
1001 | |
1002 | To be fully compatible with the Exporter and MakeMaker modules you |
1003 | should store your module's version number in a non-my package |
1004 | variable called $VERSION. This should be a floating point |
1005 | number with at least two digits after the decimal (i.e., hundredths, |
1006 | e.g, C<$VERSION = "0.01">). Don't use a "1.3.2" style version. |
1007 | See Exporter.pm in Perl5.001m or later for details. |
1008 | |
1009 | It may be handy to add a function or method to retrieve the number. |
1010 | Use the number in announcements and archive file names when |
1011 | releasing the module (ModuleName-1.02.tar.Z). |
1012 | See perldoc ExtUtils::MakeMaker.pm for details. |
1013 | |
1014 | =item How to release and distribute a module. |
1015 | |
1016 | It's good idea to post an announcement of the availability of your |
1017 | module (or the module itself if small) to the comp.lang.perl.announce |
1018 | Usenet newsgroup. This will at least ensure very wide once-off |
1019 | distribution. |
1020 | |
1021 | If possible you should place the module into a major ftp archive and |
1022 | include details of its location in your announcement. |
1023 | |
1024 | Some notes about ftp archives: Please use a long descriptive file |
5a964f20 |
1025 | name that includes the version number. Most incoming directories |
f102b883 |
1026 | will not be readable/listable, i.e., you won't be able to see your |
1027 | file after uploading it. Remember to send your email notification |
1028 | message as soon as possible after uploading else your file may get |
1029 | deleted automatically. Allow time for the file to be processed |
1030 | and/or check the file has been processed before announcing its |
1031 | location. |
1032 | |
1033 | FTP Archives for Perl Modules: |
1034 | |
1035 | Follow the instructions and links on |
1036 | |
1037 | http://franz.ww.tu-berlin.de/modulelist |
1038 | |
1039 | or upload to one of these sites: |
1040 | |
1041 | ftp://franz.ww.tu-berlin.de/incoming |
1042 | ftp://ftp.cis.ufl.edu/incoming |
1043 | |
1044 | and notify <F<upload@franz.ww.tu-berlin.de>>. |
1045 | |
1046 | By using the WWW interface you can ask the Upload Server to mirror |
1047 | your modules from your ftp or WWW site into your own directory on |
1048 | CPAN! |
1049 | |
1050 | Please remember to send me an updated entry for the Module list! |
1051 | |
1052 | =item Take care when changing a released module. |
1053 | |
7b8d334a |
1054 | Always strive to remain compatible with previous released versions. |
1055 | Otherwise try to add a mechanism to revert to the |
f102b883 |
1056 | old behaviour if people rely on it. Document incompatible changes. |
1057 | |
1058 | =back |
1059 | |
1060 | =back |
1061 | |
1062 | =head2 Guidelines for Converting Perl 4 Library Scripts into Modules |
1063 | |
1064 | =over 4 |
1065 | |
1066 | =item There is no requirement to convert anything. |
1067 | |
1068 | If it ain't broke, don't fix it! Perl 4 library scripts should |
1069 | continue to work with no problems. You may need to make some minor |
1070 | changes (like escaping non-array @'s in double quoted strings) but |
1071 | there is no need to convert a .pl file into a Module for just that. |
1072 | |
1073 | =item Consider the implications. |
1074 | |
5a964f20 |
1075 | All Perl applications that make use of the script will need to |
f102b883 |
1076 | be changed (slightly) if the script is converted into a module. Is |
1077 | it worth it unless you plan to make other changes at the same time? |
1078 | |
1079 | =item Make the most of the opportunity. |
1080 | |
1081 | If you are going to convert the script to a module you can use the |
1082 | opportunity to redesign the interface. The 'Guidelines for Module |
1083 | Creation' above include many of the issues you should consider. |
1084 | |
1085 | =item The pl2pm utility will get you started. |
1086 | |
1087 | This utility will read *.pl files (given as parameters) and write |
1088 | corresponding *.pm files. The pl2pm utilities does the following: |
1089 | |
1090 | =over 10 |
1091 | |
1092 | =item * |
1093 | Adds the standard Module prologue lines |
1094 | |
1095 | =item * |
1096 | Converts package specifiers from ' to :: |
1097 | |
1098 | =item * |
1099 | Converts die(...) to croak(...) |
1100 | |
1101 | =item * |
1102 | Several other minor changes |
1103 | |
1104 | =back |
1105 | |
1106 | Being a mechanical process pl2pm is not bullet proof. The converted |
1107 | code will need careful checking, especially any package statements. |
1108 | Don't delete the original .pl file till the new .pm one works! |
1109 | |
1110 | =back |
1111 | |
1112 | =head2 Guidelines for Reusing Application Code |
1113 | |
1114 | =over 4 |
1115 | |
1116 | =item Complete applications rarely belong in the Perl Module Library. |
1117 | |
5a964f20 |
1118 | =item Many applications contain some Perl code that could be reused. |
f102b883 |
1119 | |
1120 | Help save the world! Share your code in a form that makes it easy |
1121 | to reuse. |
1122 | |
1123 | =item Break-out the reusable code into one or more separate module files. |
1124 | |
1125 | =item Take the opportunity to reconsider and redesign the interfaces. |
1126 | |
1127 | =item In some cases the 'application' can then be reduced to a small |
1128 | |
1129 | fragment of code built on top of the reusable modules. In these cases |
1130 | the application could invoked as: |
1131 | |
5a964f20 |
1132 | % perl -e 'use Module::Name; method(@ARGV)' ... |
f102b883 |
1133 | or |
5a964f20 |
1134 | % perl -mModule::Name ... (in perl5.002 or higher) |
f102b883 |
1135 | |
1136 | =back |
1137 | |
1138 | =head1 NOTE |
1139 | |
1140 | Perl does not enforce private and public parts of its modules as you may |
1141 | have been used to in other languages like C++, Ada, or Modula-17. Perl |
1142 | doesn't have an infatuation with enforced privacy. It would prefer |
1143 | that you stayed out of its living room because you weren't invited, not |
1144 | because it has a shotgun. |
1145 | |
1146 | The module and its user have a contract, part of which is common law, |
1147 | and part of which is "written". Part of the common law contract is |
1148 | that a module doesn't pollute any namespace it wasn't asked to. The |
1149 | written contract for the module (A.K.A. documentation) may make other |
1150 | provisions. But then you know when you C<use RedefineTheWorld> that |
1151 | you're redefining the world and willing to take the consequences. |