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2e1d04bc JH |
1 | #!../miniperl |
2 | ||
3 | open (OUT, ">perlmodlib.tmp") or die $!; | |
4 | my (@pragma, @mod); | |
5 | open (MANIFEST, "../MANIFEST") or die $!; | |
6 | ||
7 | while (<MANIFEST>) { | |
8 | my $filename; | |
9 | next unless s|^lib/|| or m|^ext/|; | |
10 | ($filename) = /(\S+)/; | |
11 | $filename =~ s|^[^/]+/|| if $filename =~ s|^ext/||; | |
12 | next unless $filename =~ /\.pm$/; | |
13 | next unless open (MOD, "../lib/$filename"); | |
14 | my ($name, $thing); | |
15 | my $foundit=0; | |
16 | {local $/=""; | |
17 | while (<MOD>) { | |
18 | next unless /^=head1 NAME/; | |
19 | $foundit++; | |
20 | last; | |
21 | } | |
22 | } | |
23 | next unless $foundit; | |
24 | my $title = <MOD>; | |
25 | chomp($title); | |
26 | close MOD; | |
27 | ||
28 | my $perlname = $filename; | |
29 | $perlname =~ s|\.pm$||; | |
30 | $perlname =~ s|/|::|g; | |
31 | ||
32 | ($name, $thing) = split / - /, $title,2; | |
33 | next unless $name and $thing; | |
34 | $thing=~s/^perl pragma to //i; | |
35 | $thing=ucfirst($thing); | |
36 | $title = "=item $perlname\n\n$thing\n\n"; | |
37 | ||
38 | if ($filename=~/[A-Z]/) { | |
39 | push @mod, $title; | |
40 | } else { | |
41 | push @pragma, $title; | |
42 | } | |
43 | } | |
44 | ||
45 | print OUT <<'EOF'; | |
46 | =head1 NAME | |
47 | ||
48 | perlmodlib - constructing new Perl modules and finding existing ones | |
49 | ||
50 | =head1 DESCRIPTION | |
51 | ||
52 | =head1 THE PERL MODULE LIBRARY | |
53 | ||
54 | Many modules are included the Perl distribution. These are described | |
55 | below, and all end in F<.pm>. You may discover compiled library | |
56 | file (usually ending in F<.so>) or small pieces of modules to be | |
57 | autoloaded (ending in F<.al>); these were automatically generated | |
58 | by the installation process. You may also discover files in the | |
59 | library directory that end in either F<.pl> or F<.ph>. These are | |
60 | old libraries supplied so that old programs that use them still | |
61 | run. The F<.pl> files will all eventually be converted into standard | |
62 | modules, and the F<.ph> files made by B<h2ph> will probably end up | |
63 | as extension modules made by B<h2xs>. (Some F<.ph> values may | |
64 | already be available through the POSIX, Errno, or Fcntl modules.) | |
65 | The B<pl2pm> file in the distribution may help in your conversion, | |
66 | but it's just a mechanical process and therefore far from bulletproof. | |
67 | ||
68 | =head2 Pragmatic Modules | |
69 | ||
70 | They work somewhat like compiler directives (pragmata) in that they | |
71 | tend to affect the compilation of your program, and thus will usually | |
72 | work well only when used within a C<use>, or C<no>. Most of these | |
73 | are lexically scoped, so an inner BLOCK may countermand them | |
74 | by saying: | |
75 | ||
76 | no integer; | |
77 | no strict 'refs'; | |
78 | no warnings; | |
79 | ||
80 | which lasts until the end of that BLOCK. | |
81 | ||
82 | Some pragmas are lexically scoped--typically those that affect the | |
83 | C<$^H> hints variable. Others affect the current package instead, | |
84 | like C<use vars> and C<use subs>, which allow you to predeclare a | |
85 | variables or subroutines within a particular I<file> rather than | |
86 | just a block. Such declarations are effective for the entire file | |
87 | for which they were declared. You cannot rescind them with C<no | |
88 | vars> or C<no subs>. | |
89 | ||
90 | The following pragmas are defined (and have their own documentation). | |
91 | ||
92 | =over 12 | |
93 | ||
94 | EOF | |
95 | ||
96 | print OUT $_ for (sort @pragma); | |
97 | ||
98 | print OUT <<EOF; | |
99 | =back | |
100 | ||
101 | =head2 Standard Modules | |
102 | ||
103 | Standard, bundled modules are all expected to behave in a well-defined | |
104 | manner with respect to namespace pollution because they use the | |
105 | Exporter module. See their own documentation for details. | |
106 | ||
107 | =over 12 | |
108 | ||
109 | EOF | |
110 | ||
111 | print OUT $_ for (sort @mod); | |
112 | ||
113 | print OUT <<'EOF'; | |
114 | =back | |
115 | ||
116 | To find out I<all> modules installed on your system, including | |
117 | those without documentation or outside the standard release, | |
309a139e | 118 | just do this: |
2e1d04bc JH |
119 | |
120 | % find `perl -e 'print "@INC"'` -name '*.pm' -print | |
121 | ||
122 | They should all have their own documentation installed and accessible | |
123 | via your system man(1) command. If you do not have a B<find> | |
124 | program, you can use the Perl B<find2perl> program instead, which | |
125 | generates Perl code as output you can run through perl. If you | |
126 | have a B<man> program but it doesn't find your modules, you'll have | |
127 | to fix your manpath. See L<perl> for details. If you have no | |
128 | system B<man> command, you might try the B<perldoc> program. | |
129 | ||
130 | =head2 Extension Modules | |
131 | ||
132 | Extension modules are written in C (or a mix of Perl and C). They | |
133 | are usually dynamically loaded into Perl if and when you need them, | |
134 | but may also be be linked in statically. Supported extension modules | |
135 | include Socket, Fcntl, and POSIX. | |
136 | ||
137 | Many popular C extension modules do not come bundled (at least, not | |
138 | completely) due to their sizes, volatility, or simply lack of time | |
139 | for adequate testing and configuration across the multitude of | |
140 | platforms on which Perl was beta-tested. You are encouraged to | |
141 | look for them on CPAN (described below), or using web search engines | |
142 | like Alta Vista or Deja News. | |
143 | ||
144 | =head1 CPAN | |
145 | ||
146 | CPAN stands for Comprehensive Perl Archive Network; it's a globally | |
147 | replicated trove of Perl materials, including documentation, style | |
148 | guides, tricks and traps, alternate ports to non-Unix systems and | |
149 | occasional binary distributions for these. Search engines for | |
150 | CPAN can be found at http://cpan.perl.com/ and at | |
151 | http://theory.uwinnipeg.ca/mod_perl/cpan-search.pl . | |
152 | ||
153 | Most importantly, CPAN includes around a thousand unbundled modules, | |
154 | some of which require a C compiler to build. Major categories of | |
155 | modules are: | |
156 | ||
157 | =over | |
158 | ||
159 | =item * | |
160 | Language Extensions and Documentation Tools | |
161 | ||
162 | =item * | |
163 | Development Support | |
164 | ||
165 | =item * | |
166 | Operating System Interfaces | |
167 | ||
168 | =item * | |
169 | Networking, Device Control (modems) and InterProcess Communication | |
170 | ||
171 | =item * | |
172 | Data Types and Data Type Utilities | |
173 | ||
174 | =item * | |
175 | Database Interfaces | |
176 | ||
177 | =item * | |
178 | User Interfaces | |
179 | ||
180 | =item * | |
181 | Interfaces to / Emulations of Other Programming Languages | |
182 | ||
183 | =item * | |
184 | File Names, File Systems and File Locking (see also File Handles) | |
185 | ||
186 | =item * | |
187 | String Processing, Language Text Processing, Parsing, and Searching | |
188 | ||
189 | =item * | |
190 | Option, Argument, Parameter, and Configuration File Processing | |
191 | ||
192 | =item * | |
193 | Internationalization and Locale | |
194 | ||
195 | =item * | |
196 | Authentication, Security, and Encryption | |
197 | ||
198 | =item * | |
199 | World Wide Web, HTML, HTTP, CGI, MIME | |
200 | ||
201 | =item * | |
202 | Server and Daemon Utilities | |
203 | ||
204 | =item * | |
205 | Archiving and Compression | |
206 | ||
207 | =item * | |
208 | Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing | |
209 | ||
210 | =item * | |
211 | Mail and Usenet News | |
212 | ||
213 | =item * | |
214 | Control Flow Utilities (callbacks and exceptions etc) | |
215 | ||
216 | =item * | |
217 | File Handle and Input/Output Stream Utilities | |
218 | ||
219 | =item * | |
220 | Miscellaneous Modules | |
221 | ||
222 | =back | |
223 | ||
224 | Registered CPAN sites as of this writing include the following. | |
225 | You should try to choose one close to you: | |
226 | ||
227 | =over | |
228 | ||
229 | =item Africa | |
230 | ||
231 | South Africa ftp://ftp.is.co.za/programming/perl/CPAN/ | |
232 | ftp://ftp.saix.net/pub/CPAN/ | |
233 | ftp://ftp.sun.ac.za/CPAN/ | |
234 | ftp://ftpza.co.za/pub/mirrors/cpan/ | |
235 | ||
236 | ||
237 | =item Asia | |
238 | ||
239 | China ftp://freesoft.cei.gov.cn/pub/languages/perl/CPAN/ | |
240 | Hong Kong ftp://ftp.pacific.net.hk/pub/mirror/CPAN/ | |
241 | Indonesia ftp://malone.piksi.itb.ac.id/pub/CPAN/ | |
242 | Israel ftp://bioinfo.weizmann.ac.il/pub/software/perl/CPAN/ | |
243 | Japan ftp://ftp.dti.ad.jp/pub/lang/CPAN/ | |
244 | ftp://ftp.jaist.ac.jp/pub/lang/perl/CPAN/ | |
245 | ftp://ftp.lab.kdd.co.jp/lang/perl/CPAN/ | |
246 | ftp://ftp.meisei-u.ac.jp/pub/CPAN/ | |
247 | ftp://ftp.ring.gr.jp/pub/lang/perl/CPAN/ | |
248 | ftp://mirror.nucba.ac.jp/mirror/Perl/ | |
249 | Saudi-Arabia ftp://ftp.isu.net.sa/pub/CPAN/ | |
250 | Singapore ftp://ftp.nus.edu.sg/pub/unix/perl/CPAN/ | |
251 | South Korea ftp://ftp.bora.net/pub/CPAN/ | |
252 | ftp://ftp.kornet.net/pub/CPAN/ | |
253 | ftp://ftp.nuri.net/pub/CPAN/ | |
254 | Taiwan ftp://coda.nctu.edu.tw/computer-languages/perl/CPAN/ | |
255 | ftp://ftp.ee.ncku.edu.tw/pub3/perl/CPAN/ | |
256 | ftp://ftp1.sinica.edu.tw/pub1/perl/CPAN/ | |
257 | Thailand ftp://ftp.nectec.or.th/pub/mirrors/CPAN/ | |
258 | ||
259 | ||
260 | =item Australasia | |
261 | ||
262 | Australia ftp://cpan.topend.com.au/pub/CPAN/ | |
263 | ftp://ftp.labyrinth.net.au/pub/perl-CPAN/ | |
264 | ftp://ftp.sage-au.org.au/pub/compilers/perl/CPAN/ | |
265 | ftp://mirror.aarnet.edu.au/pub/perl/CPAN/ | |
266 | New Zealand ftp://ftp.auckland.ac.nz/pub/perl/CPAN/ | |
267 | ftp://sunsite.net.nz/pub/languages/perl/CPAN/ | |
268 | ||
269 | ||
270 | =item Central America | |
271 | ||
272 | Costa Rica ftp://ftp.ucr.ac.cr/pub/Unix/CPAN/ | |
273 | ||
274 | ||
275 | =item Europe | |
276 | ||
277 | Austria ftp://ftp.tuwien.ac.at/pub/languages/perl/CPAN/ | |
278 | Belgium ftp://ftp.kulnet.kuleuven.ac.be/pub/mirror/CPAN/ | |
279 | Bulgaria ftp://ftp.ntrl.net/pub/mirrors/CPAN/ | |
280 | Croatia ftp://ftp.linux.hr/pub/CPAN/ | |
281 | Czech Republic ftp://ftp.fi.muni.cz/pub/perl/ | |
282 | ftp://sunsite.mff.cuni.cz/Languages/Perl/CPAN/ | |
283 | Denmark ftp://sunsite.auc.dk/pub/languages/perl/CPAN/ | |
284 | Estonia ftp://ftp.ut.ee/pub/languages/perl/CPAN/ | |
285 | Finland ftp://ftp.funet.fi/pub/languages/perl/CPAN/ | |
286 | France ftp://ftp.grolier.fr/pub/perl/CPAN/ | |
287 | ftp://ftp.lip6.fr/pub/perl/CPAN/ | |
288 | ftp://ftp.oleane.net/pub/mirrors/CPAN/ | |
289 | ftp://ftp.pasteur.fr/pub/computing/CPAN/ | |
290 | ftp://ftp.uvsq.fr/pub/perl/CPAN/ | |
291 | German ftp://ftp.gigabell.net/pub/CPAN/ | |
292 | Germany ftp://ftp.archive.de.uu.net/pub/CPAN/ | |
293 | ftp://ftp.freenet.de/pub/ftp.cpan.org/pub/ | |
294 | ftp://ftp.gmd.de/packages/CPAN/ | |
295 | ftp://ftp.gwdg.de/pub/languages/perl/CPAN/ | |
296 | ||
297 | ftp://ftp.leo.org/pub/comp/general/programming/languages/script/perl/CPAN/ | |
298 | ftp://ftp.mpi-sb.mpg.de/pub/perl/CPAN/ | |
299 | ftp://ftp.rz.ruhr-uni-bochum.de/pub/CPAN/ | |
300 | ftp://ftp.uni-erlangen.de/pub/source/CPAN/ | |
301 | ftp://ftp.uni-hamburg.de/pub/soft/lang/perl/CPAN/ | |
302 | Germany ftp://ftp.archive.de.uu.net/pub/CPAN/ | |
303 | ftp://ftp.freenet.de/pub/ftp.cpan.org/pub/ | |
304 | ftp://ftp.gmd.de/packages/CPAN/ | |
305 | ftp://ftp.gwdg.de/pub/languages/perl/CPAN/ | |
306 | ||
307 | ftp://ftp.leo.org/pub/comp/general/programming/languages/script/perl/CPAN/ | |
308 | ftp://ftp.mpi-sb.mpg.de/pub/perl/CPAN/ | |
309 | ftp://ftp.rz.ruhr-uni-bochum.de/pub/CPAN/ | |
310 | ftp://ftp.uni-erlangen.de/pub/source/CPAN/ | |
311 | ftp://ftp.uni-hamburg.de/pub/soft/lang/perl/CPAN/ | |
312 | Greece ftp://ftp.ntua.gr/pub/lang/perl/ | |
313 | Hungary ftp://ftp.kfki.hu/pub/packages/perl/CPAN/ | |
314 | Iceland ftp://ftp.gm.is/pub/CPAN/ | |
315 | Ireland ftp://cpan.indigo.ie/pub/CPAN/ | |
316 | ftp://sunsite.compapp.dcu.ie/pub/perl/ | |
317 | Italy ftp://cis.uniRoma2.it/CPAN/ | |
318 | ftp://ftp.flashnet.it/pub/CPAN/ | |
319 | ftp://ftp.unina.it/pub/Other/CPAN/ | |
320 | ftp://ftp.unipi.it/pub/mirror/perl/CPAN/ | |
321 | Netherlands ftp://ftp.cs.uu.nl/mirror/CPAN/ | |
322 | ftp://ftp.nluug.nl/pub/languages/perl/CPAN/ | |
323 | Norway ftp://ftp.uit.no/pub/languages/perl/cpan/ | |
324 | ftp://sunsite.uio.no/pub/languages/perl/CPAN/ | |
325 | Poland ftp://ftp.man.torun.pl/pub/CPAN/ | |
326 | ftp://ftp.pk.edu.pl/pub/lang/perl/CPAN/ | |
327 | ftp://sunsite.icm.edu.pl/pub/CPAN/ | |
328 | Portugal ftp://ftp.ci.uminho.pt/pub/mirrors/cpan/ | |
329 | ftp://ftp.ist.utl.pt/pub/CPAN/ | |
330 | ftp://ftp.ua.pt/pub/CPAN/ | |
331 | Romania ftp://ftp.dnttm.ro/pub/CPAN/ | |
332 | Russia ftp://ftp.chg.ru/pub/lang/perl/CPAN/ | |
333 | ftp://ftp.sai.msu.su/pub/lang/perl/CPAN/ | |
334 | Slovakia ftp://ftp.entry.sk/pub/languages/perl/CPAN/ | |
335 | Slovenia ftp://ftp.arnes.si/software/perl/CPAN/ | |
336 | Spain ftp://ftp.etse.urv.es/pub/perl/ | |
337 | ftp://ftp.rediris.es/mirror/CPAN/ | |
338 | Sweden ftp://ftp.sunet.se/pub/lang/perl/CPAN/ | |
339 | Switzerland ftp://sunsite.cnlab-switch.ch/mirror/CPAN/ | |
340 | Turkey ftp://sunsite.bilkent.edu.tr/pub/languages/CPAN/ | |
341 | United Kingdom ftp://ftp.demon.co.uk/pub/mirrors/perl/CPAN/ | |
342 | ftp://ftp.flirble.org/pub/languages/perl/CPAN/ | |
343 | ||
344 | ftp://ftp.mirror.ac.uk/sites/ftp.funet.fi/pub/languages/perl/CPAN/ | |
345 | ftp://ftp.plig.org/pub/CPAN/ | |
346 | ftp://sunsite.doc.ic.ac.uk/packages/CPAN/ | |
347 | ||
348 | ||
349 | =item North America | |
350 | ||
351 | Alberta ftp://sunsite.ualberta.ca/pub/Mirror/CPAN/ | |
352 | California ftp://cpan.nas.nasa.gov/pub/perl/CPAN/ | |
353 | ftp://cpan.valueclick.com/CPAN/ | |
354 | ftp://ftp.cdrom.com/pub/perl/CPAN/ | |
355 | http://download.sourceforge.net/mirrors/CPAN/ | |
356 | Colorado ftp://ftp.cs.colorado.edu/pub/perl/CPAN/ | |
357 | Florida ftp://ftp.cise.ufl.edu/pub/perl/CPAN/ | |
358 | Georgia ftp://ftp.twoguys.org/CPAN/ | |
359 | Illinois ftp://uiarchive.uiuc.edu/pub/lang/perl/CPAN/ | |
360 | Indiana ftp://csociety-ftp.ecn.purdue.edu/pub/CPAN/ | |
361 | ftp://ftp.uwsg.indiana.edu/pub/perl/CPAN/ | |
362 | Kentucky ftp://ftp.uky.edu/CPAN/ | |
363 | Manitoba ftp://theoryx5.uwinnipeg.ca/pub/CPAN/ | |
364 | Massachusetts | |
365 | ftp://ftp.ccs.neu.edu/net/mirrors/ftp.funet.fi/pub/languages/perl/CPAN/ | |
366 | ftp://ftp.iguide.com/pub/mirrors/packages/perl/CPAN/ | |
367 | Mexico ftp://ftp.msg.com.mx/pub/CPAN/ | |
368 | New York ftp://ftp.deao.net/pub/CPAN/ | |
369 | ftp://ftp.rge.com/pub/languages/perl/ | |
370 | North Carolina ftp://ftp.duke.edu/pub/perl/ | |
371 | Nova Scotia ftp://cpan.chebucto.ns.ca/pub/CPAN/ | |
372 | Oklahoma ftp://ftp.ou.edu/mirrors/CPAN/ | |
373 | Ontario ftp://ftp.crc.ca/pub/packages/lang/perl/CPAN/ | |
374 | Oregon ftp://ftp.orst.edu/pub/packages/CPAN/ | |
375 | Pennsylvania ftp://ftp.epix.net/pub/languages/perl/ | |
376 | Tennessee ftp://ftp.sunsite.utk.edu/pub/CPAN/ | |
377 | Texas ftp://ftp.sedl.org/pub/mirrors/CPAN/ | |
378 | ftp://jhcloos.com/pub/mirror/CPAN/ | |
379 | Utah ftp://mirror.xmission.com/CPAN/ | |
380 | Virginia ftp://ftp.perl.org/pub/perl/CPAN/ | |
381 | ftp://ruff.cs.jmu.edu/pub/CPAN/ | |
382 | Washington ftp://ftp-mirror.internap.com/pub/CPAN/ | |
383 | ftp://ftp.llarian.net/pub/CPAN/ | |
384 | ftp://ftp.spu.edu/pub/CPAN/ | |
385 | ||
386 | ||
387 | =item South America | |
388 | ||
389 | Brazil ftp://cpan.if.usp.br/pub/mirror/CPAN/ | |
390 | ftp://ftp.matrix.com.br/pub/perl/ | |
391 | Chile ftp://sunsite.dcc.uchile.cl/pub/Lang/PERL/ | |
392 | ||
393 | =back | |
394 | ||
395 | For an up-to-date listing of CPAN sites, | |
396 | see http://www.perl.com/perl/CPAN/SITES or ftp://www.perl.com/CPAN/SITES . | |
397 | ||
398 | =head1 Modules: Creation, Use, and Abuse | |
399 | ||
400 | (The following section is borrowed directly from Tim Bunce's modules | |
401 | file, available at your nearest CPAN site.) | |
402 | ||
403 | Perl implements a class using a package, but the presence of a | |
404 | package doesn't imply the presence of a class. A package is just a | |
405 | namespace. A class is a package that provides subroutines that can be | |
406 | used as methods. A method is just a subroutine that expects, as its | |
407 | first argument, either the name of a package (for "static" methods), | |
408 | or a reference to something (for "virtual" methods). | |
409 | ||
410 | A module is a file that (by convention) provides a class of the same | |
411 | name (sans the .pm), plus an import method in that class that can be | |
412 | called to fetch exported symbols. This module may implement some of | |
413 | its methods by loading dynamic C or C++ objects, but that should be | |
414 | totally transparent to the user of the module. Likewise, the module | |
415 | might set up an AUTOLOAD function to slurp in subroutine definitions on | |
416 | demand, but this is also transparent. Only the F<.pm> file is required to | |
417 | exist. See L<perlsub>, L<perltoot>, and L<AutoLoader> for details about | |
418 | the AUTOLOAD mechanism. | |
419 | ||
420 | =head2 Guidelines for Module Creation | |
421 | ||
422 | =over 4 | |
423 | ||
424 | =item Do similar modules already exist in some form? | |
425 | ||
426 | If so, please try to reuse the existing modules either in whole or | |
427 | by inheriting useful features into a new class. If this is not | |
428 | practical try to get together with the module authors to work on | |
429 | extending or enhancing the functionality of the existing modules. | |
430 | A perfect example is the plethora of packages in perl4 for dealing | |
431 | with command line options. | |
432 | ||
433 | If you are writing a module to expand an already existing set of | |
434 | modules, please coordinate with the author of the package. It | |
435 | helps if you follow the same naming scheme and module interaction | |
436 | scheme as the original author. | |
437 | ||
438 | =item Try to design the new module to be easy to extend and reuse. | |
439 | ||
440 | Try to C<use warnings;> (or C<use warnings qw(...);>). | |
441 | Remember that you can add C<no warnings qw(...);> to individual blocks | |
442 | of code that need less warnings. | |
443 | ||
444 | Use blessed references. Use the two argument form of bless to bless | |
445 | into the class name given as the first parameter of the constructor, | |
446 | e.g.,: | |
447 | ||
448 | sub new { | |
449 | my $class = shift; | |
450 | return bless {}, $class; | |
451 | } | |
452 | ||
453 | or even this if you'd like it to be used as either a static | |
454 | or a virtual method. | |
455 | ||
456 | sub new { | |
457 | my $self = shift; | |
458 | my $class = ref($self) || $self; | |
459 | return bless {}, $class; | |
460 | } | |
461 | ||
462 | Pass arrays as references so more parameters can be added later | |
463 | (it's also faster). Convert functions into methods where | |
464 | appropriate. Split large methods into smaller more flexible ones. | |
465 | Inherit methods from other modules if appropriate. | |
466 | ||
467 | Avoid class name tests like: C<die "Invalid" unless ref $ref eq 'FOO'>. | |
468 | Generally you can delete the C<eq 'FOO'> part with no harm at all. | |
469 | Let the objects look after themselves! Generally, avoid hard-wired | |
470 | class names as far as possible. | |
471 | ||
472 | Avoid C<< $r->Class::func() >> where using C<@ISA=qw(... Class ...)> and | |
473 | C<< $r->func() >> would work (see L<perlbot> for more details). | |
474 | ||
475 | Use autosplit so little used or newly added functions won't be a | |
476 | burden to programs that don't use them. Add test functions to | |
477 | the module after __END__ either using AutoSplit or by saying: | |
478 | ||
479 | eval join('',<main::DATA>) || die $@ unless caller(); | |
480 | ||
481 | Does your module pass the 'empty subclass' test? If you say | |
482 | C<@SUBCLASS::ISA = qw(YOURCLASS);> your applications should be able | |
483 | to use SUBCLASS in exactly the same way as YOURCLASS. For example, | |
484 | does your application still work if you change: C<$obj = new YOURCLASS;> | |
485 | into: C<$obj = new SUBCLASS;> ? | |
486 | ||
487 | Avoid keeping any state information in your packages. It makes it | |
488 | difficult for multiple other packages to use yours. Keep state | |
489 | information in objects. | |
490 | ||
491 | Always use B<-w>. | |
492 | ||
493 | Try to C<use strict;> (or C<use strict qw(...);>). | |
494 | Remember that you can add C<no strict qw(...);> to individual blocks | |
495 | of code that need less strictness. | |
496 | ||
497 | Always use B<-w>. | |
498 | ||
499 | Follow the guidelines in the perlstyle(1) manual. | |
500 | ||
501 | Always use B<-w>. | |
502 | ||
503 | =item Some simple style guidelines | |
504 | ||
505 | The perlstyle manual supplied with Perl has many helpful points. | |
506 | ||
507 | Coding style is a matter of personal taste. Many people evolve their | |
508 | style over several years as they learn what helps them write and | |
509 | maintain good code. Here's one set of assorted suggestions that | |
510 | seem to be widely used by experienced developers: | |
511 | ||
512 | Use underscores to separate words. It is generally easier to read | |
513 | $var_names_like_this than $VarNamesLikeThis, especially for | |
514 | non-native speakers of English. It's also a simple rule that works | |
515 | consistently with VAR_NAMES_LIKE_THIS. | |
516 | ||
517 | Package/Module names are an exception to this rule. Perl informally | |
518 | reserves lowercase module names for 'pragma' modules like integer | |
519 | and strict. Other modules normally begin with a capital letter and | |
520 | use mixed case with no underscores (need to be short and portable). | |
521 | ||
522 | You may find it helpful to use letter case to indicate the scope | |
523 | or nature of a variable. For example: | |
524 | ||
525 | $ALL_CAPS_HERE constants only (beware clashes with Perl vars) | |
526 | $Some_Caps_Here package-wide global/static | |
527 | $no_caps_here function scope my() or local() variables | |
528 | ||
529 | Function and method names seem to work best as all lowercase. | |
530 | e.g., C<< $obj->as_string() >>. | |
531 | ||
532 | You can use a leading underscore to indicate that a variable or | |
533 | function should not be used outside the package that defined it. | |
534 | ||
535 | =item Select what to export. | |
536 | ||
537 | Do NOT export method names! | |
538 | ||
539 | Do NOT export anything else by default without a good reason! | |
540 | ||
541 | Exports pollute the namespace of the module user. If you must | |
542 | export try to use @EXPORT_OK in preference to @EXPORT and avoid | |
543 | short or common names to reduce the risk of name clashes. | |
544 | ||
545 | Generally anything not exported is still accessible from outside the | |
546 | module using the ModuleName::item_name (or C<< $blessed_ref->method >>) | |
547 | syntax. By convention you can use a leading underscore on names to | |
548 | indicate informally that they are 'internal' and not for public use. | |
549 | ||
550 | (It is actually possible to get private functions by saying: | |
551 | C<my $subref = sub { ... }; &$subref;>. But there's no way to call that | |
552 | directly as a method, because a method must have a name in the symbol | |
553 | table.) | |
554 | ||
555 | As a general rule, if the module is trying to be object oriented | |
556 | then export nothing. If it's just a collection of functions then | |
557 | @EXPORT_OK anything but use @EXPORT with caution. | |
558 | ||
559 | =item Select a name for the module. | |
560 | ||
561 | This name should be as descriptive, accurate, and complete as | |
562 | possible. Avoid any risk of ambiguity. Always try to use two or | |
563 | more whole words. Generally the name should reflect what is special | |
564 | about what the module does rather than how it does it. Please use | |
565 | nested module names to group informally or categorize a module. | |
566 | There should be a very good reason for a module not to have a nested name. | |
567 | Module names should begin with a capital letter. | |
568 | ||
569 | Having 57 modules all called Sort will not make life easy for anyone | |
570 | (though having 23 called Sort::Quick is only marginally better :-). | |
571 | Imagine someone trying to install your module alongside many others. | |
572 | If in any doubt ask for suggestions in comp.lang.perl.misc. | |
573 | ||
574 | If you are developing a suite of related modules/classes it's good | |
575 | practice to use nested classes with a common prefix as this will | |
576 | avoid namespace clashes. For example: Xyz::Control, Xyz::View, | |
577 | Xyz::Model etc. Use the modules in this list as a naming guide. | |
578 | ||
579 | If adding a new module to a set, follow the original author's | |
580 | standards for naming modules and the interface to methods in | |
581 | those modules. | |
582 | ||
4844a3be SP |
583 | If developing modules for private internal or project specific use, |
584 | that will never be released to the public, then you should ensure | |
585 | that their names will not clash with any future public module. You | |
586 | can do this either by using the reserved Local::* category or by | |
587 | using a category name that includes an underscore like Foo_Corp::*. | |
588 | ||
2e1d04bc JH |
589 | To be portable each component of a module name should be limited to |
590 | 11 characters. If it might be used on MS-DOS then try to ensure each is | |
591 | unique in the first 8 characters. Nested modules make this easier. | |
592 | ||
593 | =item Have you got it right? | |
594 | ||
595 | How do you know that you've made the right decisions? Have you | |
596 | picked an interface design that will cause problems later? Have | |
597 | you picked the most appropriate name? Do you have any questions? | |
598 | ||
599 | The best way to know for sure, and pick up many helpful suggestions, | |
600 | is to ask someone who knows. Comp.lang.perl.misc is read by just about | |
601 | all the people who develop modules and it's the best place to ask. | |
602 | ||
603 | All you need to do is post a short summary of the module, its | |
604 | purpose and interfaces. A few lines on each of the main methods is | |
605 | probably enough. (If you post the whole module it might be ignored | |
606 | by busy people - generally the very people you want to read it!) | |
607 | ||
608 | Don't worry about posting if you can't say when the module will be | |
609 | ready - just say so in the message. It might be worth inviting | |
610 | others to help you, they may be able to complete it for you! | |
611 | ||
612 | =item README and other Additional Files. | |
613 | ||
614 | It's well known that software developers usually fully document the | |
615 | software they write. If, however, the world is in urgent need of | |
616 | your software and there is not enough time to write the full | |
617 | documentation please at least provide a README file containing: | |
618 | ||
619 | =over 10 | |
620 | ||
621 | =item * | |
622 | A description of the module/package/extension etc. | |
623 | ||
624 | =item * | |
625 | A copyright notice - see below. | |
626 | ||
627 | =item * | |
628 | Prerequisites - what else you may need to have. | |
629 | ||
630 | =item * | |
631 | How to build it - possible changes to Makefile.PL etc. | |
632 | ||
633 | =item * | |
634 | How to install it. | |
635 | ||
636 | =item * | |
637 | Recent changes in this release, especially incompatibilities | |
638 | ||
639 | =item * | |
640 | Changes / enhancements you plan to make in the future. | |
641 | ||
642 | =back | |
643 | ||
644 | If the README file seems to be getting too large you may wish to | |
645 | split out some of the sections into separate files: INSTALL, | |
646 | Copying, ToDo etc. | |
647 | ||
648 | =over 4 | |
649 | ||
650 | =item Adding a Copyright Notice. | |
651 | ||
652 | How you choose to license your work is a personal decision. | |
653 | The general mechanism is to assert your Copyright and then make | |
654 | a declaration of how others may copy/use/modify your work. | |
655 | ||
656 | Perl, for example, is supplied with two types of licence: The GNU | |
657 | GPL and The Artistic Licence (see the files README, Copying, and | |
658 | Artistic). Larry has good reasons for NOT just using the GNU GPL. | |
659 | ||
660 | My personal recommendation, out of respect for Larry, Perl, and the | |
661 | Perl community at large is to state something simply like: | |
662 | ||
663 | Copyright (c) 1995 Your Name. All rights reserved. | |
664 | This program is free software; you can redistribute it and/or | |
665 | modify it under the same terms as Perl itself. | |
666 | ||
667 | This statement should at least appear in the README file. You may | |
668 | also wish to include it in a Copying file and your source files. | |
669 | Remember to include the other words in addition to the Copyright. | |
670 | ||
671 | =item Give the module a version/issue/release number. | |
672 | ||
673 | To be fully compatible with the Exporter and MakeMaker modules you | |
674 | should store your module's version number in a non-my package | |
675 | variable called $VERSION. This should be a floating point | |
676 | number with at least two digits after the decimal (i.e., hundredths, | |
677 | e.g, C<$VERSION = "0.01">). Don't use a "1.3.2" style version. | |
678 | See L<Exporter> for details. | |
679 | ||
680 | It may be handy to add a function or method to retrieve the number. | |
681 | Use the number in announcements and archive file names when | |
682 | releasing the module (ModuleName-1.02.tar.Z). | |
683 | See perldoc ExtUtils::MakeMaker.pm for details. | |
684 | ||
685 | =item How to release and distribute a module. | |
686 | ||
687 | It's good idea to post an announcement of the availability of your | |
688 | module (or the module itself if small) to the comp.lang.perl.announce | |
689 | Usenet newsgroup. This will at least ensure very wide once-off | |
690 | distribution. | |
691 | ||
692 | If possible, register the module with CPAN. You should | |
693 | include details of its location in your announcement. | |
694 | ||
695 | Some notes about ftp archives: Please use a long descriptive file | |
696 | name that includes the version number. Most incoming directories | |
697 | will not be readable/listable, i.e., you won't be able to see your | |
698 | file after uploading it. Remember to send your email notification | |
699 | message as soon as possible after uploading else your file may get | |
700 | deleted automatically. Allow time for the file to be processed | |
701 | and/or check the file has been processed before announcing its | |
702 | location. | |
703 | ||
704 | FTP Archives for Perl Modules: | |
705 | ||
706 | Follow the instructions and links on: | |
707 | ||
708 | http://www.perl.com/CPAN/modules/00modlist.long.html | |
709 | http://www.perl.com/CPAN/modules/04pause.html | |
710 | ||
711 | or upload to one of these sites: | |
712 | ||
713 | https://pause.kbx.de/pause/ | |
714 | http://pause.perl.org/pause/ | |
715 | ||
716 | and notify <modules@perl.org>. | |
717 | ||
718 | By using the WWW interface you can ask the Upload Server to mirror | |
719 | your modules from your ftp or WWW site into your own directory on | |
720 | CPAN! | |
721 | ||
722 | Please remember to send me an updated entry for the Module list! | |
723 | ||
724 | =item Take care when changing a released module. | |
725 | ||
726 | Always strive to remain compatible with previous released versions. | |
727 | Otherwise try to add a mechanism to revert to the | |
728 | old behavior if people rely on it. Document incompatible changes. | |
729 | ||
730 | =back | |
731 | ||
732 | =back | |
733 | ||
734 | =head2 Guidelines for Converting Perl 4 Library Scripts into Modules | |
735 | ||
736 | =over 4 | |
737 | ||
738 | =item There is no requirement to convert anything. | |
739 | ||
740 | If it ain't broke, don't fix it! Perl 4 library scripts should | |
741 | continue to work with no problems. You may need to make some minor | |
742 | changes (like escaping non-array @'s in double quoted strings) but | |
743 | there is no need to convert a .pl file into a Module for just that. | |
744 | ||
745 | =item Consider the implications. | |
746 | ||
747 | All Perl applications that make use of the script will need to | |
748 | be changed (slightly) if the script is converted into a module. Is | |
749 | it worth it unless you plan to make other changes at the same time? | |
750 | ||
751 | =item Make the most of the opportunity. | |
752 | ||
753 | If you are going to convert the script to a module you can use the | |
754 | opportunity to redesign the interface. The guidelines for module | |
755 | creation above include many of the issues you should consider. | |
756 | ||
757 | =item The pl2pm utility will get you started. | |
758 | ||
759 | This utility will read *.pl files (given as parameters) and write | |
760 | corresponding *.pm files. The pl2pm utilities does the following: | |
761 | ||
762 | =over 10 | |
763 | ||
764 | =item * | |
765 | Adds the standard Module prologue lines | |
766 | ||
767 | =item * | |
768 | Converts package specifiers from ' to :: | |
769 | ||
770 | =item * | |
771 | Converts die(...) to croak(...) | |
772 | ||
773 | =item * | |
774 | Several other minor changes | |
775 | ||
776 | =back | |
777 | ||
778 | Being a mechanical process pl2pm is not bullet proof. The converted | |
779 | code will need careful checking, especially any package statements. | |
780 | Don't delete the original .pl file till the new .pm one works! | |
781 | ||
782 | =back | |
783 | ||
784 | =head2 Guidelines for Reusing Application Code | |
785 | ||
786 | =over 4 | |
787 | ||
788 | =item Complete applications rarely belong in the Perl Module Library. | |
789 | ||
790 | =item Many applications contain some Perl code that could be reused. | |
791 | ||
792 | Help save the world! Share your code in a form that makes it easy | |
793 | to reuse. | |
794 | ||
795 | =item Break-out the reusable code into one or more separate module files. | |
796 | ||
797 | =item Take the opportunity to reconsider and redesign the interfaces. | |
798 | ||
799 | =item In some cases the 'application' can then be reduced to a small | |
800 | ||
801 | fragment of code built on top of the reusable modules. In these cases | |
802 | the application could invoked as: | |
803 | ||
804 | % perl -e 'use Module::Name; method(@ARGV)' ... | |
805 | or | |
806 | % perl -mModule::Name ... (in perl5.002 or higher) | |
807 | ||
808 | =back | |
809 | ||
810 | =head1 NOTE | |
811 | ||
812 | Perl does not enforce private and public parts of its modules as you may | |
813 | have been used to in other languages like C++, Ada, or Modula-17. Perl | |
814 | doesn't have an infatuation with enforced privacy. It would prefer | |
815 | that you stayed out of its living room because you weren't invited, not | |
816 | because it has a shotgun. | |
817 | ||
818 | The module and its user have a contract, part of which is common law, | |
819 | and part of which is "written". Part of the common law contract is | |
820 | that a module doesn't pollute any namespace it wasn't asked to. The | |
821 | written contract for the module (A.K.A. documentation) may make other | |
822 | provisions. But then you know when you C<use RedefineTheWorld> that | |
823 | you're redefining the world and willing to take the consequences. | |
824 | EOF | |
825 | ||
826 | close MANIFEST or warn "$0: failed to close MANIFEST (../MANIFEST): $!"; | |
827 | close OUT or warn "$0: failed to close OUT (perlmodlib.tmp): $!"; | |
828 |