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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 | |
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9 | Many modules are included the Perl distribution. These are described |
10 | below, and all end in F<.pm>. You may discover compiled library |
11 | file (usually ending in F<.so>) or small pieces of modules to be |
12 | autoloaded (ending in F<.al>); these were automatically generated |
13 | by the installation process. You may also discover files in the |
14 | library directory that end in either F<.pl> or F<.ph>. These are |
15 | old libraries supplied so that old programs that use them still |
16 | run. The F<.pl> files will all eventually be converted into standard |
17 | modules, and the F<.ph> files made by B<h2ph> will probably end up |
18 | as extension modules made by B<h2xs>. (Some F<.ph> values may |
19 | already be available through the POSIX, Errno, or Fcntl modules.) |
20 | The B<pl2pm> file in the distribution may help in your conversion, |
21 | but it's just a mechanical process and therefore far from bulletproof. |
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22 | |
23 | =head2 Pragmatic Modules |
24 | |
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25 | They work somewhat like compiler directives (pragmata) in that they |
26 | tend to affect the compilation of your program, and thus will usually |
27 | work well only when used within a C<use>, or C<no>. Most of these |
28 | are lexically scoped, so an inner BLOCK may countermand them |
29 | by saying: |
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30 | |
31 | no integer; |
32 | no strict 'refs'; |
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33 | no warnings; |
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34 | |
35 | which lasts until the end of that BLOCK. |
36 | |
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37 | Some pragmas are lexically scoped--typically those that affect the |
38 | C<$^H> hints variable. Others affect the current package instead, |
39 | like C<use vars> and C<use subs>, whic allow you to predeclare a |
40 | variables or subroutines within a particular I<file> rather than |
41 | just a block. Such declarations are effective for the entire file |
42 | for which they were declared. You cannot rescind them with C<no |
43 | vars> or C<no subs>. |
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44 | |
45 | The following pragmas are defined (and have their own documentation). |
46 | |
47 | =over 12 |
48 | |
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49 | =item attrs |
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50 | |
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51 | set/get attributes of a subroutine |
52 | |
53 | =item autouse |
54 | |
55 | postpone load of modules until a function is used |
56 | |
57 | =item base |
58 | |
59 | Establish IS-A relationship with base class at compile time |
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60 | |
61 | =item blib |
62 | |
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63 | Use MakeMaker's uninstalled version of a package |
64 | |
65 | =item constant |
66 | |
67 | declare constants |
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68 | |
69 | =item diagnostics |
70 | |
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71 | Perl compiler pragma to force verbose warning diagnostics |
72 | |
73 | =item fields |
74 | |
75 | compile-time class fields |
76 | |
77 | =item filetest |
78 | |
79 | control the filetest permission operators |
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80 | |
81 | =item integer |
82 | |
83 | compute arithmetic in integer instead of double |
84 | |
85 | =item less |
86 | |
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87 | perl pragma to request less of something from the compiler |
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88 | |
89 | =item lib |
90 | |
91 | manipulate @INC at compile time |
92 | |
93 | =item locale |
94 | |
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95 | use and avoid POSIX locales for built-in operations |
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96 | |
97 | =item ops |
98 | |
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99 | restrict unsafe operations when compiling |
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100 | |
101 | =item overload |
102 | |
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103 | Package for overloading perl operations |
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104 | |
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105 | =item re |
106 | |
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107 | alter regular expression behavior |
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108 | |
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109 | =item sigtrap |
110 | |
111 | enable simple signal handling |
112 | |
113 | =item strict |
114 | |
115 | restrict unsafe constructs |
116 | |
117 | =item subs |
118 | |
119 | predeclare sub names |
120 | |
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121 | =item utf8 |
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122 | |
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123 | turn on UTF-8 and Unicode support |
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124 | |
125 | =item vars |
126 | |
127 | predeclare global variable names |
128 | |
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129 | =item warnings |
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130 | |
131 | control optional warnings |
132 | |
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133 | =item vmsish |
134 | |
135 | control VMS-specific language features |
136 | |
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137 | =back |
138 | |
139 | =head2 Standard Modules |
140 | |
141 | Standard, bundled modules are all expected to behave in a well-defined |
142 | manner with respect to namespace pollution because they use the |
143 | Exporter module. See their own documentation for details. |
144 | |
145 | =over 12 |
146 | |
147 | =item AnyDBM_File |
148 | |
149 | provide framework for multiple DBMs |
150 | |
151 | =item AutoLoader |
152 | |
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153 | load subroutines only on demand |
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154 | |
155 | =item AutoSplit |
156 | |
157 | split a package for autoloading |
158 | |
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159 | =item B |
160 | |
161 | The Perl Compiler; See also L<perlcc>. |
162 | |
163 | =item B::Asmdata |
164 | |
165 | Autogenerated data about Perl ops, used to generate bytecode |
166 | |
167 | =item B::Assembler |
168 | |
169 | Assemble Perl bytecode |
170 | |
171 | =item B::Bblock |
172 | |
173 | Walk basic blocks |
174 | |
175 | =item B::Bytecode |
176 | |
177 | Perl compiler's bytecode backend |
178 | |
179 | =item B::C |
180 | |
181 | Perl compiler's C backend |
182 | |
183 | =item B::CC |
184 | |
185 | Perl compiler's optimized C translation backend |
186 | |
187 | =item B::Debug |
188 | |
189 | Walk Perl syntax tree, printing debug info about ops |
190 | |
191 | =item B::Deparse |
192 | |
193 | Perl compiler backend to produce perl code |
194 | |
195 | =item B::Disassembler |
196 | |
197 | Disassemble Perl bytecode |
198 | |
199 | =item B::Lint |
200 | |
201 | Perl lint |
202 | |
203 | =item B::Showlex |
204 | |
205 | Show lexical variables used in functions or files |
206 | |
207 | =item B::Stackobj |
208 | |
209 | Helper module for CC backend |
210 | |
211 | =item B::Terse |
212 | |
213 | Walk Perl syntax tree, printing terse info about ops |
214 | |
215 | =item B::Xref |
216 | |
217 | Generates cross reference reports for Perl programs |
218 | |
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219 | =item Benchmark |
220 | |
221 | benchmark running times of code |
222 | |
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223 | =item CGI |
224 | |
225 | Simple Common Gateway Interface Class |
226 | |
227 | =item CGI::Apache |
228 | |
229 | Make things work with CGI.pm against Perl-Apache API |
230 | |
231 | =item CGI::Carp |
232 | |
233 | CGI routines for writing to the HTTPD (or other) error log |
234 | |
235 | =item CGI::Cookie |
236 | |
237 | Interface to Netscape Cookies |
238 | |
239 | =item CGI::Fast |
240 | |
241 | CGI Interface for Fast CGI |
242 | |
243 | =item CGI::Push |
244 | |
245 | Simple Interface to Server Push |
246 | |
247 | =item CGI::Switch |
248 | |
249 | Try more than one constructors and return the first object available |
250 | |
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251 | =item CPAN |
252 | |
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253 | query, download and build perl modules from CPAN sites |
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254 | |
255 | =item CPAN::FirstTime |
256 | |
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257 | Utility for CPAN::Config file Initialization |
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258 | |
259 | =item CPAN::Nox |
260 | |
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261 | Wrapper around CPAN.pm without using any XS module |
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262 | |
263 | =item Carp |
264 | |
265 | warn of errors (from perspective of caller) |
266 | |
267 | =item Class::Struct |
268 | |
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269 | declare struct-like datatypes as Perl classes |
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270 | |
271 | =item Config |
272 | |
273 | access Perl configuration information |
274 | |
275 | =item Cwd |
276 | |
277 | get pathname of current working directory |
278 | |
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279 | =item DB |
280 | |
281 | programmatic interface to the Perl debugging API |
282 | |
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283 | =item DB_File |
284 | |
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285 | Perl5 access to Berkeley DB version 1.x |
286 | |
287 | =item Data::Dumper |
288 | |
289 | stringified perl data structures, suitable for both printing and C<eval> |
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290 | |
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291 | =item Devel::Peek |
292 | |
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293 | A data debugging tool for the XS programmer |
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294 | |
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295 | =item Devel::SelfStubber |
296 | |
297 | generate stubs for a SelfLoading module |
298 | |
299 | =item DirHandle |
300 | |
301 | supply object methods for directory handles |
302 | |
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303 | =item Dumpvalue |
304 | |
305 | provides screen dump of Perl data. |
306 | |
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307 | =item DynaLoader |
308 | |
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309 | Dynamically load C libraries into Perl code |
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310 | |
311 | =item English |
312 | |
313 | use nice English (or awk) names for ugly punctuation variables |
314 | |
315 | =item Env |
316 | |
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317 | perl module that imports environment variables |
318 | |
319 | =item Errno |
320 | |
321 | System errno constants |
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322 | |
323 | =item Exporter |
324 | |
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325 | Implements default import method for modules |
326 | |
327 | =item ExtUtils::Command |
328 | |
329 | utilities to replace common UNIX commands in Makefiles etc. |
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330 | |
331 | =item ExtUtils::Embed |
332 | |
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333 | Utilities for embedding Perl in C/C++ applications |
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334 | |
335 | =item ExtUtils::Install |
336 | |
337 | install files from here to there |
338 | |
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339 | =item ExtUtils::Installed |
340 | |
341 | Inventory management of installed modules |
342 | |
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343 | =item ExtUtils::Liblist |
344 | |
345 | determine libraries to use and how to use them |
346 | |
347 | =item ExtUtils::MM_OS2 |
348 | |
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349 | methods to override UN*X behavior in ExtUtils::MakeMaker |
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350 | |
351 | =item ExtUtils::MM_Unix |
352 | |
353 | methods used by ExtUtils::MakeMaker |
354 | |
355 | =item ExtUtils::MM_VMS |
356 | |
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357 | methods to override UN*X behavior in ExtUtils::MakeMaker |
358 | |
359 | =item ExtUtils::MM_Win32 |
360 | |
361 | methods to override UN*X behavior in ExtUtils::MakeMaker |
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362 | |
363 | =item ExtUtils::MakeMaker |
364 | |
365 | create an extension Makefile |
366 | |
367 | =item ExtUtils::Manifest |
368 | |
369 | utilities to write and check a MANIFEST file |
370 | |
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371 | =item ExtUtils::Miniperl |
372 | |
373 | write the C code for perlmain.c |
374 | |
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375 | =item ExtUtils::Mkbootstrap |
376 | |
377 | make a bootstrap file for use by DynaLoader |
378 | |
379 | =item ExtUtils::Mksymlists |
380 | |
381 | write linker options files for dynamic extension |
382 | |
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383 | =item ExtUtils::Packlist |
384 | |
385 | manage .packlist files |
386 | |
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387 | =item ExtUtils::testlib |
388 | |
389 | add blib/* directories to @INC |
390 | |
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391 | =item Fatal |
392 | |
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393 | replace functions with equivalents which succeed or die |
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394 | |
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395 | =item Fcntl |
396 | |
397 | load the C Fcntl.h defines |
398 | |
399 | =item File::Basename |
400 | |
401 | split a pathname into pieces |
402 | |
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403 | =item File::Compare |
404 | |
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405 | Compare files or filehandles |
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406 | |
407 | =item File::Copy |
408 | |
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409 | Copy files or filehandles |
410 | |
411 | =item File::DosGlob |
412 | |
413 | DOS like globbing and then some |
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414 | |
415 | =item File::Find |
416 | |
417 | traverse a file tree |
418 | |
419 | =item File::Path |
420 | |
421 | create or remove a series of directories |
422 | |
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423 | =item File::Spec |
424 | |
425 | portably perform operations on file names |
426 | |
427 | =item File::Spec::Functions |
428 | |
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429 | portably perform operations on file names |
430 | |
431 | =item File::Spec::Mac |
432 | |
433 | File::Spec for MacOS |
434 | |
435 | =item File::Spec::OS2 |
436 | |
437 | methods for OS/2 file specs |
438 | |
439 | =item File::Spec::Unix |
440 | |
441 | methods used by File::Spec |
442 | |
443 | =item File::Spec::VMS |
444 | |
445 | methods for VMS file specs |
446 | |
447 | =item File::Spec::Win32 |
448 | |
449 | methods for Win32 file specs |
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450 | |
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451 | =item File::stat |
452 | |
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453 | by-name interface to Perl's built-in stat() functions |
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454 | |
455 | =item FileCache |
456 | |
457 | keep more files open than the system permits |
458 | |
459 | =item FileHandle |
460 | |
461 | supply object methods for filehandles |
462 | |
463 | =item FindBin |
464 | |
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465 | Locate directory of original perl script |
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466 | |
467 | =item GDBM_File |
468 | |
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469 | Perl5 access to the gdbm library. |
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470 | |
471 | =item Getopt::Long |
472 | |
473 | extended processing of command line options |
474 | |
475 | =item Getopt::Std |
476 | |
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477 | Process single-character switches with switch clustering |
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478 | |
479 | =item I18N::Collate |
480 | |
481 | compare 8-bit scalar data according to the current locale |
482 | |
483 | =item IO |
484 | |
485 | load various IO modules |
486 | |
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487 | =item IO::Dir |
488 | |
489 | supply object methods for directory handles |
490 | |
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491 | =item IO::File |
492 | |
493 | supply object methods for filehandles |
494 | |
495 | =item IO::Handle |
496 | |
497 | supply object methods for I/O handles |
498 | |
499 | =item IO::Pipe |
500 | |
501 | supply object methods for pipes |
502 | |
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503 | =item IO::Poll |
504 | |
505 | Object interface to system poll call |
506 | |
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507 | =item IO::Seekable |
508 | |
509 | supply seek based methods for I/O objects |
510 | |
511 | =item IO::Select |
512 | |
513 | OO interface to the select system call |
514 | |
515 | =item IO::Socket |
516 | |
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517 | Object interface to socket communications |
518 | |
519 | =item IO::Socket::INET |
520 | |
521 | Object interface for AF_INET domain sockets |
522 | |
523 | =item IO::Socket::UNIX |
524 | |
525 | Object interface for AF_UNIX domain sockets |
526 | |
527 | =item IPC::Msg |
528 | |
529 | SysV Msg IPC object class |
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530 | |
531 | =item IPC::Open2 |
532 | |
533 | open a process for both reading and writing |
534 | |
535 | =item IPC::Open3 |
536 | |
537 | open a process for reading, writing, and error handling |
538 | |
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539 | =item IPC::Semaphore |
540 | |
541 | SysV Semaphore IPC object class |
542 | |
543 | =item IPC::SysV |
544 | |
545 | SysV IPC constants |
546 | |
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547 | =item Math::BigFloat |
548 | |
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549 | Arbitrary length float math package |
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550 | |
551 | =item Math::BigInt |
552 | |
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553 | Arbitrary size integer math package |
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554 | |
555 | =item Math::Complex |
556 | |
557 | complex numbers and associated mathematical functions |
558 | |
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559 | =item Math::Trig |
560 | |
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561 | trigonometric functions |
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562 | |
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563 | =item NDBM_File |
564 | |
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565 | Tied access to ndbm files |
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566 | |
567 | =item Net::Ping |
568 | |
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569 | check a remote host for reachability |
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570 | |
571 | =item Net::hostent |
572 | |
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573 | by-name interface to Perl's built-in gethost*() functions |
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574 | |
575 | =item Net::netent |
576 | |
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577 | by-name interface to Perl's built-in getnet*() functions |
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578 | |
579 | =item Net::protoent |
580 | |
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581 | by-name interface to Perl's built-in getproto*() functions |
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582 | |
583 | =item Net::servent |
584 | |
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585 | by-name interface to Perl's built-in getserv*() functions |
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586 | |
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587 | =item O |
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588 | |
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589 | Generic interface to Perl Compiler backends |
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590 | |
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591 | =item Opcode |
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592 | |
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593 | Disable named opcodes when compiling perl code |
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594 | |
595 | =item POSIX |
596 | |
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597 | Perl interface to IEEE Std 1003.1 |
598 | |
599 | =item Pod::Html |
600 | |
601 | module to convert pod files to HTML |
602 | |
603 | =item Pod::Text |
604 | |
605 | convert POD data to formatted ASCII text |
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606 | |
607 | =item SDBM_File |
608 | |
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609 | Tied access to sdbm files |
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610 | |
611 | =item Safe |
612 | |
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613 | Compile and execute code in restricted compartments |
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614 | |
615 | =item Search::Dict |
616 | |
617 | search for key in dictionary file |
618 | |
619 | =item SelectSaver |
620 | |
621 | save and restore selected file handle |
622 | |
623 | =item SelfLoader |
624 | |
625 | load functions only on demand |
626 | |
627 | =item Shell |
628 | |
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629 | run shell commands transparently within perl |
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630 | |
631 | =item Socket |
632 | |
633 | load the C socket.h defines and structure manipulators |
634 | |
635 | =item Symbol |
636 | |
637 | manipulate Perl symbols and their names |
638 | |
639 | =item Sys::Hostname |
640 | |
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641 | Try every conceivable way to get hostname |
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642 | |
643 | =item Sys::Syslog |
644 | |
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645 | Perl interface to the UNIX syslog(3) calls |
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646 | |
647 | =item Term::Cap |
648 | |
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649 | Perl termcap interface |
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650 | |
651 | =item Term::Complete |
652 | |
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653 | Perl word completion module |
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654 | |
655 | =item Term::ReadLine |
656 | |
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657 | Perl interface to various C<readline> packages. |
658 | |
659 | =item Test |
660 | |
661 | provides a simple framework for writing test scripts |
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662 | |
663 | =item Test::Harness |
664 | |
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665 | run perl standard test scripts with statistics |
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666 | |
667 | =item Text::Abbrev |
668 | |
669 | create an abbreviation table from a list |
670 | |
671 | =item Text::ParseWords |
672 | |
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673 | parse text into an array of tokens or array of arrays |
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674 | |
675 | =item Text::Soundex |
676 | |
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677 | Implementation of the Soundex Algorithm as Described by Knuth |
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678 | |
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679 | =item Text::Tabs -- expand and unexpand tabs per the unix expand(1) and unexpand(1) |
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680 | |
681 | =item Text::Wrap |
682 | |
683 | line wrapping to form simple paragraphs |
684 | |
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685 | =item Thread |
686 | |
687 | multithreading |
688 | |
689 | =item Thread::Queue |
690 | |
691 | thread-safe queues |
692 | |
693 | =item Thread::Semaphore |
694 | |
695 | thread-safe semaphores |
696 | |
697 | =item Thread::Signal |
698 | |
699 | Start a thread which runs signal handlers reliably |
700 | |
701 | =item Thread::Specific |
702 | |
703 | thread-specific keys |
704 | |
705 | =item Tie::Array |
706 | |
707 | base class for tied arrays |
708 | |
709 | =item Tie::Handle |
710 | |
711 | base class definitions for tied handles |
712 | |
713 | =item Tie::Hash, Tie::StdHash |
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714 | |
715 | base class definitions for tied hashes |
716 | |
717 | =item Tie::RefHash |
718 | |
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719 | use references as hash keys |
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720 | |
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721 | =item Tie::Scalar, Tie::StdScalar |
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722 | |
723 | base class definitions for tied scalars |
724 | |
725 | =item Tie::SubstrHash |
726 | |
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727 | Fixed-table-size, fixed-key-length hashing |
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728 | |
729 | =item Time::Local |
730 | |
731 | efficiently compute time from local and GMT time |
732 | |
733 | =item Time::gmtime |
734 | |
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735 | by-name interface to Perl's built-in gmtime() function |
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736 | |
737 | =item Time::localtime |
738 | |
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739 | by-name interface to Perl's built-in localtime() function |
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740 | |
741 | =item Time::tm |
742 | |
743 | internal object used by Time::gmtime and Time::localtime |
744 | |
745 | =item UNIVERSAL |
746 | |
747 | base class for ALL classes (blessed references) |
748 | |
749 | =item User::grent |
750 | |
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751 | by-name interface to Perl's built-in getgr*() functions |
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752 | |
753 | =item User::pwent |
754 | |
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755 | by-name interface to Perl's built-in getpw*() functions |
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756 | |
757 | =back |
758 | |
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759 | To find out I<all> modules installed on your system, including |
760 | those without documentation or outside the standard release, |
761 | jus tdo this: |
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762 | |
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763 | % find `perl -e 'print "@INC"'` -name '*.pm' -print |
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764 | |
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765 | They should all have their own documentation installed and accessible |
766 | via your system man(1) command. If you do not have a B<find> |
767 | program, you can use the Perl B<find2perl> program instead, which |
768 | generates Perl code as output you can run through perl. If you |
769 | have a B<man> program but it doesn't find your modules, you'll have |
770 | to fix your manpath. See L<perl> for details. If you have no |
771 | system B<man> command, you might try the B<perldoc> program. |
f102b883 |
772 | |
773 | =head2 Extension Modules |
774 | |
19799a22 |
775 | Extension modules are written in C (or a mix of Perl and C). They |
776 | are usually dynamically loaded into Perl if and when you need them, |
777 | but may also be be linked in statically. Supported extension modules |
778 | include Socket, Fcntl, and POSIX. |
f102b883 |
779 | |
780 | Many popular C extension modules do not come bundled (at least, not |
19799a22 |
781 | completely) due to their sizes, volatility, or simply lack of time |
782 | for adequate testing and configuration across the multitude of |
783 | platforms on which Perl was beta-tested. You are encouraged to |
784 | look for them on CPAN (described below), or using web search engines |
785 | like Alta Vista or Deja News. |
f102b883 |
786 | |
787 | =head1 CPAN |
788 | |
19799a22 |
789 | CPAN stands for Comprehensive Perl Archive Network; it's a globally |
790 | replicated trove of Perl materials, including documentation, style |
791 | guides, tricks and trap, alternate ports to non-Unix systems and |
792 | occasional binary distributions for these. Search engines for |
793 | CPAN can be found at http://cpan.perl.com/ and at |
794 | http://theory.uwinnipeg.ca/mod_perl/cpan-search.pl . |
795 | |
796 | Most importantly, CPAN includes around a thousand unbundled modules, |
797 | some of which require a C compiler to build. Major categories of |
798 | modules are: |
f102b883 |
799 | |
800 | =over |
801 | |
802 | =item * |
803 | Language Extensions and Documentation Tools |
804 | |
805 | =item * |
806 | Development Support |
807 | |
808 | =item * |
809 | Operating System Interfaces |
810 | |
811 | =item * |
812 | Networking, Device Control (modems) and InterProcess Communication |
813 | |
814 | =item * |
815 | Data Types and Data Type Utilities |
816 | |
817 | =item * |
818 | Database Interfaces |
819 | |
820 | =item * |
821 | User Interfaces |
822 | |
823 | =item * |
824 | Interfaces to / Emulations of Other Programming Languages |
825 | |
826 | =item * |
827 | File Names, File Systems and File Locking (see also File Handles) |
828 | |
829 | =item * |
830 | String Processing, Language Text Processing, Parsing, and Searching |
831 | |
832 | =item * |
833 | Option, Argument, Parameter, and Configuration File Processing |
834 | |
835 | =item * |
836 | Internationalization and Locale |
837 | |
838 | =item * |
839 | Authentication, Security, and Encryption |
840 | |
841 | =item * |
842 | World Wide Web, HTML, HTTP, CGI, MIME |
843 | |
844 | =item * |
845 | Server and Daemon Utilities |
846 | |
847 | =item * |
848 | Archiving and Compression |
849 | |
850 | =item * |
851 | Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing |
852 | |
853 | =item * |
854 | Mail and Usenet News |
855 | |
856 | =item * |
857 | Control Flow Utilities (callbacks and exceptions etc) |
858 | |
859 | =item * |
860 | File Handle and Input/Output Stream Utilities |
861 | |
862 | =item * |
863 | Miscellaneous Modules |
864 | |
865 | =back |
866 | |
19799a22 |
867 | Registered CPAN sites as of this writing include the following. |
f102b883 |
868 | You should try to choose one close to you: |
869 | |
870 | =over |
871 | |
19799a22 |
872 | =item Africa |
f102b883 |
873 | |
be94a901 |
874 | South Africa ftp://ftp.is.co.za/programming/perl/CPAN/ |
875 | ftp://ftpza.co.za/pub/mirrors/cpan/ |
f102b883 |
876 | |
19799a22 |
877 | =item Asia |
f102b883 |
878 | |
be94a901 |
879 | China ftp://freesoft.cei.gov.cn/pub/languages/perl/CPAN/ |
880 | Hong Kong ftp://ftp.hkstar.com/pub/CPAN/ |
881 | Israel ftp://bioinfo.weizmann.ac.il/pub/software/perl/CPAN/ |
882 | Japan ftp://ftp.dti.ad.jp/pub/lang/CPAN/ |
883 | ftp://ftp.jaist.ac.jp/pub/lang/perl/CPAN/ |
884 | ftp://ftp.lab.kdd.co.jp/lang/perl/CPAN/ |
885 | ftp://ftp.meisei-u.ac.jp/pub/CPAN/ |
19799a22 |
886 | ftp://ftp.ring.gr.jp/pub/lang/perl/CPAN/ |
be94a901 |
887 | ftp://mirror.nucba.ac.jp/mirror/Perl/ |
888 | Singapore ftp://ftp.nus.edu.sg/pub/unix/perl/CPAN/ |
889 | South Korea ftp://ftp.bora.net/pub/CPAN/ |
890 | ftp://ftp.nuri.net/pub/CPAN/ |
891 | Taiwan ftp://ftp.wownet.net/pub2/PERL/ |
892 | ftp://ftp1.sinica.edu.tw/pub1/perl/CPAN/ |
893 | Thailand ftp://ftp.cs.riubon.ac.th/pub/mirrors/CPAN/ |
894 | ftp://ftp.nectec.or.th/pub/mirrors/CPAN/ |
f102b883 |
895 | |
19799a22 |
896 | =item Australasia |
f102b883 |
897 | |
be94a901 |
898 | Australia ftp://cpan.topend.com.au/pub/CPAN/ |
899 | ftp://ftp.labyrinth.net.au/pub/perl/CPAN/ |
900 | ftp://ftp.sage-au.org.au/pub/compilers/perl/CPAN/ |
901 | ftp://mirror.aarnet.edu.au/pub/perl/CPAN/ |
902 | New Zealand ftp://ftp.auckland.ac.nz/pub/perl/CPAN/ |
903 | ftp://sunsite.net.nz/pub/languages/perl/CPAN/ |
904 | |
be94a901 |
905 | Central America |
906 | |
907 | Costa Rica ftp://ftp.ucr.ac.cr/pub/Unix/CPAN/ |
f102b883 |
908 | |
19799a22 |
909 | =item Europe |
f102b883 |
910 | |
be94a901 |
911 | Austria ftp://ftp.tuwien.ac.at/pub/languages/perl/CPAN/ |
912 | Belgium ftp://ftp.kulnet.kuleuven.ac.be/pub/mirror/CPAN/ |
913 | Bulgaria ftp://ftp.ntrl.net/pub/mirrors/CPAN/ |
914 | Croatia ftp://ftp.linux.hr/pub/CPAN/ |
915 | Czech Republic ftp://ftp.fi.muni.cz/pub/perl/ |
916 | ftp://sunsite.mff.cuni.cz/Languages/Perl/CPAN/ |
917 | Denmark ftp://sunsite.auc.dk/pub/languages/perl/CPAN/ |
918 | Estonia ftp://ftp.ut.ee/pub/languages/perl/CPAN/ |
919 | Finland ftp://ftp.funet.fi/pub/languages/perl/CPAN/ |
920 | France ftp://ftp.lip6.fr/pub/perl/CPAN/ |
921 | ftp://ftp.oleane.net/pub/mirrors/CPAN/ |
922 | ftp://ftp.pasteur.fr/pub/computing/CPAN/ |
923 | Germany ftp://ftp.archive.de.uu.net/pub/CPAN/ |
924 | ftp://ftp.gmd.de/packages/CPAN/ |
925 | ftp://ftp.gwdg.de/pub/languages/perl/CPAN/ |
926 | ftp://ftp.leo.org/pub/comp/programming/languages/script/perl/CPAN/ |
927 | ftp://ftp.mpi-sb.mpg.de/pub/perl/CPAN/ |
928 | ftp://ftp.rz.ruhr-uni-bochum.de/pub/CPAN/ |
929 | ftp://ftp.uni-erlangen.de/pub/source/CPAN/ |
930 | ftp://ftp.uni-hamburg.de/pub/soft/lang/perl/CPAN/ |
931 | Greece ftp://ftp.ntua.gr/pub/lang/perl/ |
932 | Hungary ftp://ftp.kfki.hu/pub/packages/perl/CPAN/ |
933 | Ireland ftp://sunsite.compapp.dcu.ie/pub/perl/ |
934 | Italy ftp://cis.uniRoma2.it/CPAN/ |
935 | ftp://ftp.flashnet.it/pub/CPAN/ |
19799a22 |
936 | ftp://ftp.unina.it/pub/Other/CPAN/ |
be94a901 |
937 | ftp://ftp.unipi.it/pub/mirror/perl/CPAN/ |
938 | Netherlands ftp://ftp.cs.uu.nl/mirror/CPAN/ |
19799a22 |
939 | ftp://ftp.EU.net/packages/cpan/ |
be94a901 |
940 | ftp://ftp.nluug.nl/pub/languages/perl/CPAN/ |
941 | Norway ftp://ftp.uit.no/pub/languages/perl/cpan/ |
942 | ftp://sunsite.uio.no/pub/languages/perl/CPAN/ |
943 | Poland ftp://ftp.man.szczecin.pl/pub/perl/CPAN/ |
944 | ftp://ftp.man.torun.pl/pub/doc/CPAN/ |
945 | ftp://ftp.pk.edu.pl/pub/lang/perl/CPAN/ |
946 | ftp://sunsite.icm.edu.pl/pub/CPAN/ |
947 | Portugal ftp://ftp.ci.uminho.pt/pub/mirrors/cpan/ |
19799a22 |
948 | ftp://ftp.ist.utl.pt/pub/CPAN/ |
be94a901 |
949 | ftp://ftp.ua.pt/pub/CPAN/ |
950 | Romania ftp://ftp.dntis.ro/pub/mirrors/perl-cpan/ |
951 | ftp://ftp.dnttm.ro/pub/CPAN/ |
19799a22 |
952 | Russia ftp://ftp.chg.ru/pub/lang/perl/CPAN/ |
be94a901 |
953 | ftp://ftp.sai.msu.su/pub/lang/perl/CPAN/ |
954 | Slovakia ftp://ftp.entry.sk/pub/languages/perl/CPAN/ |
955 | Slovenia ftp://ftp.arnes.si/software/perl/CPAN/ |
956 | Spain ftp://ftp.etse.urv.es/pub/perl/ |
957 | ftp://ftp.rediris.es/mirror/CPAN/ |
958 | Sweden ftp://ftp.sunet.se/pub/lang/perl/CPAN/ |
959 | Switzerland ftp://sunsite.cnlab-switch.ch/mirror/CPAN/ |
960 | Turkey ftp://sunsite.bilkent.edu.tr/pub/languages/CPAN/ |
961 | United Kingdom ftp://ftp.demon.co.uk/pub/mirrors/perl/CPAN/ |
962 | ftp://ftp.flirble.org/pub/languages/perl/CPAN/ |
963 | ftp://ftp.plig.org/pub/CPAN/ |
964 | ftp://sunsite.doc.ic.ac.uk/packages/CPAN/ |
965 | ftp://unix.hensa.ac.uk/mirrors/perl-CPAN/ |
f102b883 |
966 | |
19799a22 |
967 | =item North America |
f102b883 |
968 | |
be94a901 |
969 | Alberta ftp://sunsite.ualberta.ca/pub/Mirror/CPAN/ |
19799a22 |
970 | California ftp://cpan.nas.nasa.gov/pub/perl/CPAN/ |
971 | ftp://ftp.cdrom.com/pub/perl/CPAN/ |
be94a901 |
972 | ftp://ftp.digital.com/pub/plan/perl/CPAN/ |
973 | Colorado ftp://ftp.cs.colorado.edu/pub/perl/CPAN/ |
974 | Florida ftp://ftp.cise.ufl.edu/pub/perl/CPAN/ |
975 | Illinois ftp://uiarchive.uiuc.edu/pub/lang/perl/CPAN/ |
976 | Indiana ftp://csociety-ftp.ecn.purdue.edu/pub/CPAN/ |
977 | ftp://ftp.uwsg.indiana.edu/pub/perl/CPAN/ |
978 | Manitoba ftp://theory.uwinnipeg.ca/pub/CPAN/ |
979 | Massachusetts ftp://ftp.ccs.neu.edu/net/mirrors/ftp.funet.fi/pub/languages/perl/CPAN/ |
980 | ftp://ftp.iguide.com/pub/mirrors/packages/perl/CPAN/ |
19799a22 |
981 | Mexico ftp://ftp.msg.com.mx/pub/CPAN/ |
982 | Minnesota ftp://ftp.midearthbbs.com/CPAN/ |
be94a901 |
983 | New York ftp://ftp.rge.com/pub/languages/perl/ |
984 | North Carolina ftp://ftp.duke.edu/pub/perl/ |
985 | Oklahoma ftp://ftp.ou.edu/mirrors/CPAN/ |
19799a22 |
986 | Ontario ftp://ftp.crc.ca/pub/packages/lang/perl/CPAN/ |
be94a901 |
987 | Oregon ftp://ftp.orst.edu/pub/packages/CPAN/ |
988 | Pennsylvania ftp://ftp.epix.net/pub/languages/perl/ |
989 | Texas ftp://ftp.sedl.org/pub/mirrors/CPAN/ |
990 | Utah ftp://mirror.xmission.com/CPAN/ |
991 | Virginia ftp://ftp.perl.org/pub/perl/CPAN/ |
992 | ftp://ruff.cs.jmu.edu/pub/CPAN/ |
19799a22 |
993 | Washington ftp://ftp-mirror.internap.com/pub/CPAN/ |
994 | ftp://ftp.spu.edu/pub/CPAN/ |
f102b883 |
995 | |
19799a22 |
996 | =item South America |
f102b883 |
997 | |
be94a901 |
998 | Brazil ftp://cpan.if.usp.br/pub/mirror/CPAN/ |
19799a22 |
999 | Chile ftp://sunsite.dcc.uchile.cl/pub/Lang/perl/CPAN/ |
f102b883 |
1000 | |
1001 | =back |
1002 | |
1003 | For an up-to-date listing of CPAN sites, |
19799a22 |
1004 | see http://www.perl.com/perl/CPAN or ftp://www.perl.com/perl/ . |
f102b883 |
1005 | |
1006 | =head1 Modules: Creation, Use, and Abuse |
1007 | |
1008 | (The following section is borrowed directly from Tim Bunce's modules |
1009 | file, available at your nearest CPAN site.) |
1010 | |
1011 | Perl implements a class using a package, but the presence of a |
1012 | package doesn't imply the presence of a class. A package is just a |
1013 | namespace. A class is a package that provides subroutines that can be |
1014 | used as methods. A method is just a subroutine that expects, as its |
1015 | first argument, either the name of a package (for "static" methods), |
1016 | or a reference to something (for "virtual" methods). |
1017 | |
1018 | A module is a file that (by convention) provides a class of the same |
1019 | name (sans the .pm), plus an import method in that class that can be |
1020 | called to fetch exported symbols. This module may implement some of |
1021 | its methods by loading dynamic C or C++ objects, but that should be |
1022 | totally transparent to the user of the module. Likewise, the module |
1023 | might set up an AUTOLOAD function to slurp in subroutine definitions on |
1024 | demand, but this is also transparent. Only the F<.pm> file is required to |
1025 | exist. See L<perlsub>, L<perltoot>, and L<AutoLoader> for details about |
1026 | the AUTOLOAD mechanism. |
1027 | |
1028 | =head2 Guidelines for Module Creation |
1029 | |
1030 | =over 4 |
1031 | |
1032 | =item Do similar modules already exist in some form? |
1033 | |
1034 | If so, please try to reuse the existing modules either in whole or |
1035 | by inheriting useful features into a new class. If this is not |
1036 | practical try to get together with the module authors to work on |
1037 | extending or enhancing the functionality of the existing modules. |
1038 | A perfect example is the plethora of packages in perl4 for dealing |
1039 | with command line options. |
1040 | |
1041 | If you are writing a module to expand an already existing set of |
1042 | modules, please coordinate with the author of the package. It |
1043 | helps if you follow the same naming scheme and module interaction |
1044 | scheme as the original author. |
1045 | |
1046 | =item Try to design the new module to be easy to extend and reuse. |
1047 | |
19799a22 |
1048 | Always use B<-w>. |
1049 | |
f102b883 |
1050 | Use blessed references. Use the two argument form of bless to bless |
1051 | into the class name given as the first parameter of the constructor, |
1052 | e.g.,: |
1053 | |
1054 | sub new { |
1055 | my $class = shift; |
1056 | return bless {}, $class; |
1057 | } |
1058 | |
1059 | or even this if you'd like it to be used as either a static |
1060 | or a virtual method. |
1061 | |
1062 | sub new { |
1063 | my $self = shift; |
1064 | my $class = ref($self) || $self; |
1065 | return bless {}, $class; |
1066 | } |
1067 | |
1068 | Pass arrays as references so more parameters can be added later |
1069 | (it's also faster). Convert functions into methods where |
1070 | appropriate. Split large methods into smaller more flexible ones. |
1071 | Inherit methods from other modules if appropriate. |
1072 | |
1073 | Avoid class name tests like: C<die "Invalid" unless ref $ref eq 'FOO'>. |
19799a22 |
1074 | Generally you can delete the C<eq 'FOO'> part with no harm at all. |
f102b883 |
1075 | Let the objects look after themselves! Generally, avoid hard-wired |
1076 | class names as far as possible. |
1077 | |
1078 | Avoid C<$r-E<gt>Class::func()> where using C<@ISA=qw(... Class ...)> and |
1079 | C<$r-E<gt>func()> would work (see L<perlbot> for more details). |
1080 | |
1081 | Use autosplit so little used or newly added functions won't be a |
5a964f20 |
1082 | burden to programs that don't use them. Add test functions to |
f102b883 |
1083 | the module after __END__ either using AutoSplit or by saying: |
1084 | |
1085 | eval join('',<main::DATA>) || die $@ unless caller(); |
1086 | |
1087 | Does your module pass the 'empty subclass' test? If you say |
19799a22 |
1088 | C<@SUBCLASS::ISA = qw(YOURCLASS);> your applications should be able |
f102b883 |
1089 | to use SUBCLASS in exactly the same way as YOURCLASS. For example, |
1090 | does your application still work if you change: C<$obj = new YOURCLASS;> |
1091 | into: C<$obj = new SUBCLASS;> ? |
1092 | |
1093 | Avoid keeping any state information in your packages. It makes it |
1094 | difficult for multiple other packages to use yours. Keep state |
1095 | information in objects. |
1096 | |
19799a22 |
1097 | Always use B<-w>. |
1098 | |
1099 | Try to C<use strict;> (or C<use strict qw(...);>). |
f102b883 |
1100 | Remember that you can add C<no strict qw(...);> to individual blocks |
19799a22 |
1101 | of code that need less strictness. |
1102 | |
1103 | Always use B<-w>. |
1104 | |
f102b883 |
1105 | Follow the guidelines in the perlstyle(1) manual. |
1106 | |
19799a22 |
1107 | Always use B<-w>. |
1108 | |
f102b883 |
1109 | =item Some simple style guidelines |
1110 | |
5a964f20 |
1111 | The perlstyle manual supplied with Perl has many helpful points. |
f102b883 |
1112 | |
1113 | Coding style is a matter of personal taste. Many people evolve their |
1114 | style over several years as they learn what helps them write and |
1115 | maintain good code. Here's one set of assorted suggestions that |
1116 | seem to be widely used by experienced developers: |
1117 | |
1118 | Use underscores to separate words. It is generally easier to read |
1119 | $var_names_like_this than $VarNamesLikeThis, especially for |
1120 | non-native speakers of English. It's also a simple rule that works |
1121 | consistently with VAR_NAMES_LIKE_THIS. |
1122 | |
1123 | Package/Module names are an exception to this rule. Perl informally |
1124 | reserves lowercase module names for 'pragma' modules like integer |
1125 | and strict. Other modules normally begin with a capital letter and |
1126 | use mixed case with no underscores (need to be short and portable). |
1127 | |
1128 | You may find it helpful to use letter case to indicate the scope |
1129 | or nature of a variable. For example: |
1130 | |
5a964f20 |
1131 | $ALL_CAPS_HERE constants only (beware clashes with Perl vars) |
f102b883 |
1132 | $Some_Caps_Here package-wide global/static |
1133 | $no_caps_here function scope my() or local() variables |
1134 | |
1135 | Function and method names seem to work best as all lowercase. |
1136 | e.g., C<$obj-E<gt>as_string()>. |
1137 | |
1138 | You can use a leading underscore to indicate that a variable or |
1139 | function should not be used outside the package that defined it. |
1140 | |
1141 | =item Select what to export. |
1142 | |
1143 | Do NOT export method names! |
1144 | |
1145 | Do NOT export anything else by default without a good reason! |
1146 | |
1147 | Exports pollute the namespace of the module user. If you must |
1148 | export try to use @EXPORT_OK in preference to @EXPORT and avoid |
1149 | short or common names to reduce the risk of name clashes. |
1150 | |
1151 | Generally anything not exported is still accessible from outside the |
1152 | module using the ModuleName::item_name (or C<$blessed_ref-E<gt>method>) |
1153 | syntax. By convention you can use a leading underscore on names to |
1154 | indicate informally that they are 'internal' and not for public use. |
1155 | |
1156 | (It is actually possible to get private functions by saying: |
1157 | C<my $subref = sub { ... }; &$subref;>. But there's no way to call that |
1158 | directly as a method, because a method must have a name in the symbol |
1159 | table.) |
1160 | |
1161 | As a general rule, if the module is trying to be object oriented |
1162 | then export nothing. If it's just a collection of functions then |
1163 | @EXPORT_OK anything but use @EXPORT with caution. |
1164 | |
1165 | =item Select a name for the module. |
1166 | |
1167 | This name should be as descriptive, accurate, and complete as |
1168 | possible. Avoid any risk of ambiguity. Always try to use two or |
1169 | more whole words. Generally the name should reflect what is special |
1170 | about what the module does rather than how it does it. Please use |
1171 | nested module names to group informally or categorize a module. |
1172 | There should be a very good reason for a module not to have a nested name. |
1173 | Module names should begin with a capital letter. |
1174 | |
1175 | Having 57 modules all called Sort will not make life easy for anyone |
1176 | (though having 23 called Sort::Quick is only marginally better :-). |
1177 | Imagine someone trying to install your module alongside many others. |
1178 | If in any doubt ask for suggestions in comp.lang.perl.misc. |
1179 | |
1180 | If you are developing a suite of related modules/classes it's good |
1181 | practice to use nested classes with a common prefix as this will |
1182 | avoid namespace clashes. For example: Xyz::Control, Xyz::View, |
1183 | Xyz::Model etc. Use the modules in this list as a naming guide. |
1184 | |
1185 | If adding a new module to a set, follow the original author's |
1186 | standards for naming modules and the interface to methods in |
1187 | those modules. |
1188 | |
1189 | To be portable each component of a module name should be limited to |
1190 | 11 characters. If it might be used on MS-DOS then try to ensure each is |
1191 | unique in the first 8 characters. Nested modules make this easier. |
1192 | |
1193 | =item Have you got it right? |
1194 | |
1195 | How do you know that you've made the right decisions? Have you |
1196 | picked an interface design that will cause problems later? Have |
1197 | you picked the most appropriate name? Do you have any questions? |
1198 | |
1199 | The best way to know for sure, and pick up many helpful suggestions, |
1200 | is to ask someone who knows. Comp.lang.perl.misc is read by just about |
1201 | all the people who develop modules and it's the best place to ask. |
1202 | |
1203 | All you need to do is post a short summary of the module, its |
1204 | purpose and interfaces. A few lines on each of the main methods is |
1205 | probably enough. (If you post the whole module it might be ignored |
1206 | by busy people - generally the very people you want to read it!) |
1207 | |
1208 | Don't worry about posting if you can't say when the module will be |
1209 | ready - just say so in the message. It might be worth inviting |
1210 | others to help you, they may be able to complete it for you! |
1211 | |
1212 | =item README and other Additional Files. |
1213 | |
1214 | It's well known that software developers usually fully document the |
1215 | software they write. If, however, the world is in urgent need of |
1216 | your software and there is not enough time to write the full |
1217 | documentation please at least provide a README file containing: |
1218 | |
1219 | =over 10 |
1220 | |
1221 | =item * |
1222 | A description of the module/package/extension etc. |
1223 | |
1224 | =item * |
1225 | A copyright notice - see below. |
1226 | |
1227 | =item * |
1228 | Prerequisites - what else you may need to have. |
1229 | |
1230 | =item * |
1231 | How to build it - possible changes to Makefile.PL etc. |
1232 | |
1233 | =item * |
1234 | How to install it. |
1235 | |
1236 | =item * |
1237 | Recent changes in this release, especially incompatibilities |
1238 | |
1239 | =item * |
1240 | Changes / enhancements you plan to make in the future. |
1241 | |
1242 | =back |
1243 | |
1244 | If the README file seems to be getting too large you may wish to |
1245 | split out some of the sections into separate files: INSTALL, |
1246 | Copying, ToDo etc. |
1247 | |
1248 | =over 4 |
1249 | |
1250 | =item Adding a Copyright Notice. |
1251 | |
1252 | How you choose to license your work is a personal decision. |
1253 | The general mechanism is to assert your Copyright and then make |
1254 | a declaration of how others may copy/use/modify your work. |
1255 | |
1256 | Perl, for example, is supplied with two types of licence: The GNU |
1257 | GPL and The Artistic Licence (see the files README, Copying, and |
1258 | Artistic). Larry has good reasons for NOT just using the GNU GPL. |
1259 | |
1260 | My personal recommendation, out of respect for Larry, Perl, and the |
5a964f20 |
1261 | Perl community at large is to state something simply like: |
f102b883 |
1262 | |
1263 | Copyright (c) 1995 Your Name. All rights reserved. |
1264 | This program is free software; you can redistribute it and/or |
1265 | modify it under the same terms as Perl itself. |
1266 | |
1267 | This statement should at least appear in the README file. You may |
1268 | also wish to include it in a Copying file and your source files. |
1269 | Remember to include the other words in addition to the Copyright. |
1270 | |
1271 | =item Give the module a version/issue/release number. |
1272 | |
1273 | To be fully compatible with the Exporter and MakeMaker modules you |
1274 | should store your module's version number in a non-my package |
1275 | variable called $VERSION. This should be a floating point |
1276 | number with at least two digits after the decimal (i.e., hundredths, |
1277 | e.g, C<$VERSION = "0.01">). Don't use a "1.3.2" style version. |
19799a22 |
1278 | See L<Exporter> for details. |
f102b883 |
1279 | |
1280 | It may be handy to add a function or method to retrieve the number. |
1281 | Use the number in announcements and archive file names when |
1282 | releasing the module (ModuleName-1.02.tar.Z). |
1283 | See perldoc ExtUtils::MakeMaker.pm for details. |
1284 | |
1285 | =item How to release and distribute a module. |
1286 | |
1287 | It's good idea to post an announcement of the availability of your |
1288 | module (or the module itself if small) to the comp.lang.perl.announce |
1289 | Usenet newsgroup. This will at least ensure very wide once-off |
1290 | distribution. |
1291 | |
19799a22 |
1292 | If possible, register the module with CPAN. You should |
f102b883 |
1293 | include details of its location in your announcement. |
1294 | |
1295 | Some notes about ftp archives: Please use a long descriptive file |
5a964f20 |
1296 | name that includes the version number. Most incoming directories |
f102b883 |
1297 | will not be readable/listable, i.e., you won't be able to see your |
1298 | file after uploading it. Remember to send your email notification |
1299 | message as soon as possible after uploading else your file may get |
1300 | deleted automatically. Allow time for the file to be processed |
1301 | and/or check the file has been processed before announcing its |
1302 | location. |
1303 | |
1304 | FTP Archives for Perl Modules: |
1305 | |
1306 | Follow the instructions and links on |
1307 | |
1308 | http://franz.ww.tu-berlin.de/modulelist |
1309 | |
1310 | or upload to one of these sites: |
1311 | |
1312 | ftp://franz.ww.tu-berlin.de/incoming |
1313 | ftp://ftp.cis.ufl.edu/incoming |
1314 | |
1315 | and notify <F<upload@franz.ww.tu-berlin.de>>. |
1316 | |
1317 | By using the WWW interface you can ask the Upload Server to mirror |
1318 | your modules from your ftp or WWW site into your own directory on |
1319 | CPAN! |
1320 | |
1321 | Please remember to send me an updated entry for the Module list! |
1322 | |
1323 | =item Take care when changing a released module. |
1324 | |
7b8d334a |
1325 | Always strive to remain compatible with previous released versions. |
1326 | Otherwise try to add a mechanism to revert to the |
19799a22 |
1327 | old behavior if people rely on it. Document incompatible changes. |
f102b883 |
1328 | |
1329 | =back |
1330 | |
1331 | =back |
1332 | |
1333 | =head2 Guidelines for Converting Perl 4 Library Scripts into Modules |
1334 | |
1335 | =over 4 |
1336 | |
1337 | =item There is no requirement to convert anything. |
1338 | |
1339 | If it ain't broke, don't fix it! Perl 4 library scripts should |
1340 | continue to work with no problems. You may need to make some minor |
1341 | changes (like escaping non-array @'s in double quoted strings) but |
1342 | there is no need to convert a .pl file into a Module for just that. |
1343 | |
1344 | =item Consider the implications. |
1345 | |
5a964f20 |
1346 | All Perl applications that make use of the script will need to |
f102b883 |
1347 | be changed (slightly) if the script is converted into a module. Is |
1348 | it worth it unless you plan to make other changes at the same time? |
1349 | |
1350 | =item Make the most of the opportunity. |
1351 | |
1352 | If you are going to convert the script to a module you can use the |
19799a22 |
1353 | opportunity to redesign the interface. The guidelines for module |
1354 | creation above include many of the issues you should consider. |
f102b883 |
1355 | |
1356 | =item The pl2pm utility will get you started. |
1357 | |
1358 | This utility will read *.pl files (given as parameters) and write |
1359 | corresponding *.pm files. The pl2pm utilities does the following: |
1360 | |
1361 | =over 10 |
1362 | |
1363 | =item * |
1364 | Adds the standard Module prologue lines |
1365 | |
1366 | =item * |
1367 | Converts package specifiers from ' to :: |
1368 | |
1369 | =item * |
1370 | Converts die(...) to croak(...) |
1371 | |
1372 | =item * |
1373 | Several other minor changes |
1374 | |
1375 | =back |
1376 | |
1377 | Being a mechanical process pl2pm is not bullet proof. The converted |
1378 | code will need careful checking, especially any package statements. |
1379 | Don't delete the original .pl file till the new .pm one works! |
1380 | |
1381 | =back |
1382 | |
1383 | =head2 Guidelines for Reusing Application Code |
1384 | |
1385 | =over 4 |
1386 | |
1387 | =item Complete applications rarely belong in the Perl Module Library. |
1388 | |
5a964f20 |
1389 | =item Many applications contain some Perl code that could be reused. |
f102b883 |
1390 | |
1391 | Help save the world! Share your code in a form that makes it easy |
1392 | to reuse. |
1393 | |
1394 | =item Break-out the reusable code into one or more separate module files. |
1395 | |
1396 | =item Take the opportunity to reconsider and redesign the interfaces. |
1397 | |
1398 | =item In some cases the 'application' can then be reduced to a small |
1399 | |
1400 | fragment of code built on top of the reusable modules. In these cases |
1401 | the application could invoked as: |
1402 | |
5a964f20 |
1403 | % perl -e 'use Module::Name; method(@ARGV)' ... |
f102b883 |
1404 | or |
5a964f20 |
1405 | % perl -mModule::Name ... (in perl5.002 or higher) |
f102b883 |
1406 | |
1407 | =back |
1408 | |
1409 | =head1 NOTE |
1410 | |
1411 | Perl does not enforce private and public parts of its modules as you may |
1412 | have been used to in other languages like C++, Ada, or Modula-17. Perl |
1413 | doesn't have an infatuation with enforced privacy. It would prefer |
1414 | that you stayed out of its living room because you weren't invited, not |
1415 | because it has a shotgun. |
1416 | |
1417 | The module and its user have a contract, part of which is common law, |
1418 | and part of which is "written". Part of the common law contract is |
1419 | that a module doesn't pollute any namespace it wasn't asked to. The |
1420 | written contract for the module (A.K.A. documentation) may make other |
1421 | provisions. But then you know when you C<use RedefineTheWorld> that |
1422 | you're redefining the world and willing to take the consequences. |