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1 | ############################################################################# |
2 | # Pod/Parser.pm -- package which defines a base class for parsing POD docs. |
3 | # |
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4 | # Copyright (C) 1996-1999 by Bradford Appleton. All rights reserved. |
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5 | # This file is part of "PodParser". PodParser is free software; |
6 | # you can redistribute it and/or modify it under the same terms |
7 | # as Perl itself. |
8 | ############################################################################# |
9 | |
10 | package Pod::Parser; |
11 | |
12 | use vars qw($VERSION); |
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13 | $VERSION = 1.085; ## Current version of this package |
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14 | require 5.004; ## requires this Perl version or later |
15 | |
16 | ############################################################################# |
17 | |
18 | =head1 NAME |
19 | |
20 | Pod::Parser - base class for creating POD filters and translators |
21 | |
22 | =head1 SYNOPSIS |
23 | |
24 | use Pod::Parser; |
25 | |
26 | package MyParser; |
27 | @ISA = qw(Pod::Parser); |
28 | |
29 | sub command { |
30 | my ($parser, $command, $paragraph, $line_num) = @_; |
31 | ## Interpret the command and its text; sample actions might be: |
32 | if ($command eq 'head1') { ... } |
33 | elsif ($command eq 'head2') { ... } |
34 | ## ... other commands and their actions |
35 | my $out_fh = $parser->output_handle(); |
36 | my $expansion = $parser->interpolate($paragraph, $line_num); |
37 | print $out_fh $expansion; |
38 | } |
39 | |
40 | sub verbatim { |
41 | my ($parser, $paragraph, $line_num) = @_; |
42 | ## Format verbatim paragraph; sample actions might be: |
43 | my $out_fh = $parser->output_handle(); |
44 | print $out_fh $paragraph; |
45 | } |
46 | |
47 | sub textblock { |
48 | my ($parser, $paragraph, $line_num) = @_; |
49 | ## Translate/Format this block of text; sample actions might be: |
50 | my $out_fh = $parser->output_handle(); |
51 | my $expansion = $parser->interpolate($paragraph, $line_num); |
52 | print $out_fh $expansion; |
53 | } |
54 | |
55 | sub interior_sequence { |
56 | my ($parser, $seq_command, $seq_argument) = @_; |
57 | ## Expand an interior sequence; sample actions might be: |
58 | return "*$seq_argument*" if ($seq_command = 'B'); |
59 | return "`$seq_argument'" if ($seq_command = 'C'); |
60 | return "_${seq_argument}_'" if ($seq_command = 'I'); |
61 | ## ... other sequence commands and their resulting text |
62 | } |
63 | |
64 | package main; |
65 | |
66 | ## Create a parser object and have it parse file whose name was |
67 | ## given on the command-line (use STDIN if no files were given). |
68 | $parser = new MyParser(); |
69 | $parser->parse_from_filehandle(\*STDIN) if (@ARGV == 0); |
70 | for (@ARGV) { $parser->parse_from_file($_); } |
71 | |
72 | =head1 REQUIRES |
73 | |
74 | perl5.004, Pod::InputObjects, Exporter, FileHandle, Carp |
75 | |
76 | =head1 EXPORTS |
77 | |
78 | Nothing. |
79 | |
80 | =head1 DESCRIPTION |
81 | |
82 | B<Pod::Parser> is a base class for creating POD filters and translators. |
83 | It handles most of the effort involved with parsing the POD sections |
84 | from an input stream, leaving subclasses free to be concerned only with |
85 | performing the actual translation of text. |
86 | |
87 | B<Pod::Parser> parses PODs, and makes method calls to handle the various |
88 | components of the POD. Subclasses of B<Pod::Parser> override these methods |
89 | to translate the POD into whatever output format they desire. |
90 | |
91 | =head1 QUICK OVERVIEW |
92 | |
93 | To create a POD filter for translating POD documentation into some other |
94 | format, you create a subclass of B<Pod::Parser> which typically overrides |
95 | just the base class implementation for the following methods: |
96 | |
97 | =over 2 |
98 | |
99 | =item * |
100 | |
101 | B<command()> |
102 | |
103 | =item * |
104 | |
105 | B<verbatim()> |
106 | |
107 | =item * |
108 | |
109 | B<textblock()> |
110 | |
111 | =item * |
112 | |
113 | B<interior_sequence()> |
114 | |
115 | =back |
116 | |
117 | You may also want to override the B<begin_input()> and B<end_input()> |
118 | methods for your subclass (to perform any needed per-file and/or |
119 | per-document initialization or cleanup). |
120 | |
121 | If you need to perform any preprocesssing of input before it is parsed |
122 | you may want to override one or more of B<preprocess_line()> and/or |
123 | B<preprocess_paragraph()>. |
124 | |
125 | Sometimes it may be necessary to make more than one pass over the input |
126 | files. If this is the case you have several options. You can make the |
127 | first pass using B<Pod::Parser> and override your methods to store the |
128 | intermediate results in memory somewhere for the B<end_pod()> method to |
129 | process. You could use B<Pod::Parser> for several passes with an |
130 | appropriate state variable to control the operation for each pass. If |
131 | your input source can't be reset to start at the beginning, you can |
132 | store it in some other structure as a string or an array and have that |
133 | structure implement a B<getline()> method (which is all that |
134 | B<parse_from_filehandle()> uses to read input). |
135 | |
136 | Feel free to add any member data fields you need to keep track of things |
137 | like current font, indentation, horizontal or vertical position, or |
138 | whatever else you like. Be sure to read L<"PRIVATE METHODS AND DATA"> |
139 | to avoid name collisions. |
140 | |
141 | For the most part, the B<Pod::Parser> base class should be able to |
142 | do most of the input parsing for you and leave you free to worry about |
143 | how to intepret the commands and translate the result. |
144 | |
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145 | Note that all we have described here in this quick overview overview is |
146 | the simplest most striaghtforward use of B<Pod::Parser> to do stream-based |
147 | parsing. It is also possible to use the B<Pod::Parser::parse_text> function |
148 | to do more sophisticated tree-based parsing. See L<"TREE-BASED PARSING">. |
149 | |
150 | =head1 PARSING OPTIONS |
151 | |
152 | A I<parse-option> is simply a named option of B<Pod::Parser> with a |
153 | value that corresponds to a certain specified behavior. These various |
154 | behaviors of B<Pod::Parser> may be enabled/disabled by setting or |
155 | or unsetting one or more I<parse-options> using the B<parseopts()> method. |
156 | The set of currently accepted parse-options is as follows: |
157 | |
158 | =over 3 |
159 | |
160 | =item B<-want_nonPODs> (default: unset) |
161 | |
162 | Normally (by default) B<Pod::Parser> will only provide access to |
163 | the POD sections of the input. Input paragraphs that are not part |
164 | of the POD-format documentation are not made available to the caller |
165 | (not even using B<preprocess_paragraph()>). Setting this option to a |
166 | non-empty, non-zero value will allow B<preprocess_paragraph()> to see |
167 | non-POD sectioins of the input as well as POD sections. The B<cutting()> |
168 | method can be used to determine if the corresponding paragraph is a POD |
169 | paragraph, or some other input paragraph. |
170 | |
171 | =item B<-process_cut_cmd> (default: unset) |
172 | |
173 | Normally (by default) B<Pod::Parser> handles the C<=cut> POD directive |
174 | by itself and does not pass it on to the caller for processing. Setting |
175 | this option to non-empty, non-zero value will cause B<Pod::Parser> to |
176 | pass the C<=cut> directive to the caller just like any other POD command |
177 | (and hence it may be processed by the B<command()> method). |
178 | |
179 | B<Pod::Parser> will still interpret the C<=cut> directive to mean that |
180 | "cutting mode" has been (re)entered, but the caller will get a chance |
181 | to capture the actual C<=cut> paragraph itself for whatever purpose |
182 | it desires. |
183 | |
184 | =back |
185 | |
186 | Please see L<"parseopts()"> for a complete description of the interface |
187 | for the setting and unsetting of parse-options. |
188 | |
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189 | =cut |
190 | |
191 | ############################################################################# |
192 | |
193 | use vars qw(@ISA); |
194 | use strict; |
195 | #use diagnostics; |
196 | use Pod::InputObjects; |
197 | use Carp; |
198 | use FileHandle; |
199 | use Exporter; |
200 | @ISA = qw(Exporter); |
201 | |
202 | ## These "variables" are used as local "glob aliases" for performance |
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203 | use vars qw(%myData %myOpts @input_stack); |
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204 | |
205 | ############################################################################# |
206 | |
207 | =head1 RECOMMENDED SUBROUTINE/METHOD OVERRIDES |
208 | |
209 | B<Pod::Parser> provides several methods which most subclasses will probably |
210 | want to override. These methods are as follows: |
211 | |
212 | =cut |
213 | |
214 | ##--------------------------------------------------------------------------- |
215 | |
216 | =head1 B<command()> |
217 | |
218 | $parser->command($cmd,$text,$line_num,$pod_para); |
219 | |
220 | This method should be overridden by subclasses to take the appropriate |
221 | action when a POD command paragraph (denoted by a line beginning with |
222 | "=") is encountered. When such a POD directive is seen in the input, |
223 | this method is called and is passed: |
224 | |
225 | =over 3 |
226 | |
227 | =item C<$cmd> |
228 | |
229 | the name of the command for this POD paragraph |
230 | |
231 | =item C<$text> |
232 | |
233 | the paragraph text for the given POD paragraph command. |
234 | |
235 | =item C<$line_num> |
236 | |
237 | the line-number of the beginning of the paragraph |
238 | |
239 | =item C<$pod_para> |
240 | |
241 | a reference to a C<Pod::Paragraph> object which contains further |
242 | information about the paragraph command (see L<Pod::InputObjects> |
243 | for details). |
244 | |
245 | =back |
246 | |
247 | B<Note> that this method I<is> called for C<=pod> paragraphs. |
248 | |
249 | The base class implementation of this method simply treats the raw POD |
250 | command as normal block of paragraph text (invoking the B<textblock()> |
251 | method with the command paragraph). |
252 | |
253 | =cut |
254 | |
255 | sub command { |
256 | my ($self, $cmd, $text, $line_num, $pod_para) = @_; |
257 | ## Just treat this like a textblock |
258 | $self->textblock($pod_para->raw_text(), $line_num, $pod_para); |
259 | } |
260 | |
261 | ##--------------------------------------------------------------------------- |
262 | |
263 | =head1 B<verbatim()> |
264 | |
265 | $parser->verbatim($text,$line_num,$pod_para); |
266 | |
267 | This method may be overridden by subclasses to take the appropriate |
268 | action when a block of verbatim text is encountered. It is passed the |
269 | following parameters: |
270 | |
271 | =over 3 |
272 | |
273 | =item C<$text> |
274 | |
275 | the block of text for the verbatim paragraph |
276 | |
277 | =item C<$line_num> |
278 | |
279 | the line-number of the beginning of the paragraph |
280 | |
281 | =item C<$pod_para> |
282 | |
283 | a reference to a C<Pod::Paragraph> object which contains further |
284 | information about the paragraph (see L<Pod::InputObjects> |
285 | for details). |
286 | |
287 | =back |
288 | |
289 | The base class implementation of this method simply prints the textblock |
290 | (unmodified) to the output filehandle. |
291 | |
292 | =cut |
293 | |
294 | sub verbatim { |
295 | my ($self, $text, $line_num, $pod_para) = @_; |
296 | my $out_fh = $self->{_OUTPUT}; |
297 | print $out_fh $text; |
298 | } |
299 | |
300 | ##--------------------------------------------------------------------------- |
301 | |
302 | =head1 B<textblock()> |
303 | |
304 | $parser->textblock($text,$line_num,$pod_para); |
305 | |
306 | This method may be overridden by subclasses to take the appropriate |
307 | action when a normal block of POD text is encountered (although the base |
308 | class method will usually do what you want). It is passed the following |
309 | parameters: |
310 | |
311 | =over 3 |
312 | |
313 | =item C<$text> |
314 | |
315 | the block of text for the a POD paragraph |
316 | |
317 | =item C<$line_num> |
318 | |
319 | the line-number of the beginning of the paragraph |
320 | |
321 | =item C<$pod_para> |
322 | |
323 | a reference to a C<Pod::Paragraph> object which contains further |
324 | information about the paragraph (see L<Pod::InputObjects> |
325 | for details). |
326 | |
327 | =back |
328 | |
329 | In order to process interior sequences, subclasses implementations of |
330 | this method will probably want to invoke either B<interpolate()> or |
331 | B<parse_text()>, passing it the text block C<$text>, and the corresponding |
332 | line number in C<$line_num>, and then perform any desired processing upon |
333 | the returned result. |
334 | |
335 | The base class implementation of this method simply prints the text block |
336 | as it occurred in the input stream). |
337 | |
338 | =cut |
339 | |
340 | sub textblock { |
341 | my ($self, $text, $line_num, $pod_para) = @_; |
342 | my $out_fh = $self->{_OUTPUT}; |
343 | print $out_fh $self->interpolate($text, $line_num); |
344 | } |
345 | |
346 | ##--------------------------------------------------------------------------- |
347 | |
348 | =head1 B<interior_sequence()> |
349 | |
350 | $parser->interior_sequence($seq_cmd,$seq_arg,$pod_seq); |
351 | |
352 | This method should be overridden by subclasses to take the appropriate |
353 | action when an interior sequence is encountered. An interior sequence is |
354 | an embedded command within a block of text which appears as a command |
355 | name (usually a single uppercase character) followed immediately by a |
356 | string of text which is enclosed in angle brackets. This method is |
357 | passed the sequence command C<$seq_cmd> and the corresponding text |
358 | C<$seq_arg>. It is invoked by the B<interpolate()> method for each interior |
359 | sequence that occurs in the string that it is passed. It should return |
360 | the desired text string to be used in place of the interior sequence. |
361 | The C<$pod_seq> argument is a reference to a C<Pod::InteriorSequence> |
362 | object which contains further information about the interior sequence. |
363 | Please see L<Pod::InputObjects> for details if you need to access this |
364 | additional information. |
365 | |
366 | Subclass implementations of this method may wish to invoke the |
367 | B<nested()> method of C<$pod_seq> to see if it is nested inside |
368 | some other interior-sequence (and if so, which kind). |
369 | |
370 | The base class implementation of the B<interior_sequence()> method |
371 | simply returns the raw text of the interior sequence (as it occurred |
372 | in the input) to the caller. |
373 | |
374 | =cut |
375 | |
376 | sub interior_sequence { |
377 | my ($self, $seq_cmd, $seq_arg, $pod_seq) = @_; |
378 | ## Just return the raw text of the interior sequence |
379 | return $pod_seq->raw_text(); |
380 | } |
381 | |
382 | ############################################################################# |
383 | |
384 | =head1 OPTIONAL SUBROUTINE/METHOD OVERRIDES |
385 | |
386 | B<Pod::Parser> provides several methods which subclasses may want to override |
387 | to perform any special pre/post-processing. These methods do I<not> have to |
388 | be overridden, but it may be useful for subclasses to take advantage of them. |
389 | |
390 | =cut |
391 | |
392 | ##--------------------------------------------------------------------------- |
393 | |
394 | =head1 B<new()> |
395 | |
396 | my $parser = Pod::Parser->new(); |
397 | |
398 | This is the constructor for B<Pod::Parser> and its subclasses. You |
399 | I<do not> need to override this method! It is capable of constructing |
400 | subclass objects as well as base class objects, provided you use |
401 | any of the following constructor invocation styles: |
402 | |
403 | my $parser1 = MyParser->new(); |
404 | my $parser2 = new MyParser(); |
405 | my $parser3 = $parser2->new(); |
406 | |
407 | where C<MyParser> is some subclass of B<Pod::Parser>. |
408 | |
409 | Using the syntax C<MyParser::new()> to invoke the constructor is I<not> |
410 | recommended, but if you insist on being able to do this, then the |
411 | subclass I<will> need to override the B<new()> constructor method. If |
412 | you do override the constructor, you I<must> be sure to invoke the |
413 | B<initialize()> method of the newly blessed object. |
414 | |
415 | Using any of the above invocations, the first argument to the |
416 | constructor is always the corresponding package name (or object |
417 | reference). No other arguments are required, but if desired, an |
418 | associative array (or hash-table) my be passed to the B<new()> |
419 | constructor, as in: |
420 | |
421 | my $parser1 = MyParser->new( MYDATA => $value1, MOREDATA => $value2 ); |
422 | my $parser2 = new MyParser( -myflag => 1 ); |
423 | |
424 | All arguments passed to the B<new()> constructor will be treated as |
425 | key/value pairs in a hash-table. The newly constructed object will be |
426 | initialized by copying the contents of the given hash-table (which may |
427 | have been empty). The B<new()> constructor for this class and all of its |
428 | subclasses returns a blessed reference to the initialized object (hash-table). |
429 | |
430 | =cut |
431 | |
432 | sub new { |
433 | ## Determine if we were called via an object-ref or a classname |
434 | my $this = shift; |
435 | my $class = ref($this) || $this; |
436 | ## Any remaining arguments are treated as initial values for the |
437 | ## hash that is used to represent this object. |
438 | my %params = @_; |
439 | my $self = { %params }; |
440 | ## Bless ourselves into the desired class and perform any initialization |
441 | bless $self, $class; |
442 | $self->initialize(); |
443 | return $self; |
444 | } |
445 | |
446 | ##--------------------------------------------------------------------------- |
447 | |
448 | =head1 B<initialize()> |
449 | |
450 | $parser->initialize(); |
451 | |
452 | This method performs any necessary object initialization. It takes no |
453 | arguments (other than the object instance of course, which is typically |
454 | copied to a local variable named C<$self>). If subclasses override this |
455 | method then they I<must> be sure to invoke C<$self-E<gt>SUPER::initialize()>. |
456 | |
457 | =cut |
458 | |
459 | sub initialize { |
460 | #my $self = shift; |
461 | #return; |
462 | } |
463 | |
464 | ##--------------------------------------------------------------------------- |
465 | |
466 | =head1 B<begin_pod()> |
467 | |
468 | $parser->begin_pod(); |
469 | |
470 | This method is invoked at the beginning of processing for each POD |
471 | document that is encountered in the input. Subclasses should override |
472 | this method to perform any per-document initialization. |
473 | |
474 | =cut |
475 | |
476 | sub begin_pod { |
477 | #my $self = shift; |
478 | #return; |
479 | } |
480 | |
481 | ##--------------------------------------------------------------------------- |
482 | |
483 | =head1 B<begin_input()> |
484 | |
485 | $parser->begin_input(); |
486 | |
487 | This method is invoked by B<parse_from_filehandle()> immediately I<before> |
488 | processing input from a filehandle. The base class implementation does |
489 | nothing, however, subclasses may override it to perform any per-file |
490 | initializations. |
491 | |
492 | Note that if multiple files are parsed for a single POD document |
493 | (perhaps the result of some future C<=include> directive) this method |
494 | is invoked for every file that is parsed. If you wish to perform certain |
495 | initializations once per document, then you should use B<begin_pod()>. |
496 | |
497 | =cut |
498 | |
499 | sub begin_input { |
500 | #my $self = shift; |
501 | #return; |
502 | } |
503 | |
504 | ##--------------------------------------------------------------------------- |
505 | |
506 | =head1 B<end_input()> |
507 | |
508 | $parser->end_input(); |
509 | |
510 | This method is invoked by B<parse_from_filehandle()> immediately I<after> |
511 | processing input from a filehandle. The base class implementation does |
512 | nothing, however, subclasses may override it to perform any per-file |
513 | cleanup actions. |
514 | |
515 | Please note that if multiple files are parsed for a single POD document |
516 | (perhaps the result of some kind of C<=include> directive) this method |
517 | is invoked for every file that is parsed. If you wish to perform certain |
518 | cleanup actions once per document, then you should use B<end_pod()>. |
519 | |
520 | =cut |
521 | |
522 | sub end_input { |
523 | #my $self = shift; |
524 | #return; |
525 | } |
526 | |
527 | ##--------------------------------------------------------------------------- |
528 | |
529 | =head1 B<end_pod()> |
530 | |
531 | $parser->end_pod(); |
532 | |
533 | This method is invoked at the end of processing for each POD document |
534 | that is encountered in the input. Subclasses should override this method |
535 | to perform any per-document finalization. |
536 | |
537 | =cut |
538 | |
539 | sub end_pod { |
540 | #my $self = shift; |
541 | #return; |
542 | } |
543 | |
544 | ##--------------------------------------------------------------------------- |
545 | |
546 | =head1 B<preprocess_line()> |
547 | |
548 | $textline = $parser->preprocess_line($text, $line_num); |
549 | |
550 | This method should be overridden by subclasses that wish to perform |
551 | any kind of preprocessing for each I<line> of input (I<before> it has |
552 | been determined whether or not it is part of a POD paragraph). The |
553 | parameter C<$text> is the input line; and the parameter C<$line_num> is |
554 | the line number of the corresponding text line. |
555 | |
556 | The value returned should correspond to the new text to use in its |
557 | place. If the empty string or an undefined value is returned then no |
558 | further processing will be performed for this line. |
559 | |
560 | Please note that the B<preprocess_line()> method is invoked I<before> |
561 | the B<preprocess_paragraph()> method. After all (possibly preprocessed) |
562 | lines in a paragraph have been assembled together and it has been |
563 | determined that the paragraph is part of the POD documentation from one |
564 | of the selected sections, then B<preprocess_paragraph()> is invoked. |
565 | |
566 | The base class implementation of this method returns the given text. |
567 | |
568 | =cut |
569 | |
570 | sub preprocess_line { |
571 | my ($self, $text, $line_num) = @_; |
572 | return $text; |
573 | } |
574 | |
575 | ##--------------------------------------------------------------------------- |
576 | |
577 | =head1 B<preprocess_paragraph()> |
578 | |
579 | $textblock = $parser->preprocess_paragraph($text, $line_num); |
580 | |
581 | This method should be overridden by subclasses that wish to perform any |
582 | kind of preprocessing for each block (paragraph) of POD documentation |
583 | that appears in the input stream. The parameter C<$text> is the POD |
584 | paragraph from the input file; and the parameter C<$line_num> is the |
585 | line number for the beginning of the corresponding paragraph. |
586 | |
587 | The value returned should correspond to the new text to use in its |
588 | place If the empty string is returned or an undefined value is |
589 | returned, then the given C<$text> is ignored (not processed). |
590 | |
591 | This method is invoked after gathering up all thelines in a paragraph |
592 | but before trying to further parse or interpret them. After |
593 | B<preprocess_paragraph()> returns, the current cutting state (which |
594 | is returned by C<$self-E<gt>cutting()>) is examined. If it evaluates |
595 | to false then input text (including the given C<$text>) is cut (not |
596 | processed) until the next POD directive is encountered. |
597 | |
598 | Please note that the B<preprocess_line()> method is invoked I<before> |
599 | the B<preprocess_paragraph()> method. After all (possibly preprocessed) |
600 | lines in a paragraph have been assembled together and it has been |
601 | determined that the paragraph is part of the POD documentation from one |
602 | of the selected sections, then B<preprocess_paragraph()> is invoked. |
603 | |
604 | The base class implementation of this method returns the given text. |
605 | |
606 | =cut |
607 | |
608 | sub preprocess_paragraph { |
609 | my ($self, $text, $line_num) = @_; |
610 | return $text; |
611 | } |
612 | |
613 | ############################################################################# |
614 | |
615 | =head1 METHODS FOR PARSING AND PROCESSING |
616 | |
617 | B<Pod::Parser> provides several methods to process input text. These |
664bb207 |
618 | methods typically won't need to be overridden (and in some cases they |
619 | can't be overridden), but subclasses may want to invoke them to exploit |
620 | their functionality. |
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621 | |
622 | =cut |
623 | |
624 | ##--------------------------------------------------------------------------- |
625 | |
626 | =head1 B<parse_text()> |
627 | |
628 | $ptree1 = $parser->parse_text($text, $line_num); |
629 | $ptree2 = $parser->parse_text({%opts}, $text, $line_num); |
630 | $ptree3 = $parser->parse_text(\%opts, $text, $line_num); |
631 | |
632 | This method is useful if you need to perform your own interpolation |
633 | of interior sequences and can't rely upon B<interpolate> to expand |
634 | them in simple bottom-up order order. |
635 | |
636 | The parameter C<$text> is a string or block of text to be parsed |
637 | for interior sequences; and the parameter C<$line_num> is the |
638 | line number curresponding to the beginning of C<$text>. |
639 | |
640 | B<parse_text()> will parse the given text into a parse-tree of "nodes." |
641 | and interior-sequences. Each "node" in the parse tree is either a |
642 | text-string, or a B<Pod::InteriorSequence>. The result returned is a |
643 | parse-tree of type B<Pod::ParseTree>. Please see L<Pod::InputObjects> |
644 | for more information about B<Pod::InteriorSequence> and B<Pod::ParseTree>. |
645 | |
646 | If desired, an optional hash-ref may be specified as the first argument |
647 | to customize certain aspects of the parse-tree that is created and |
648 | returned. The set of recognized option keywords are: |
649 | |
650 | =over 3 |
651 | |
652 | =item B<-expand_seq> =E<gt> I<code-ref>|I<method-name> |
653 | |
654 | Normally, the parse-tree returned by B<parse_text()> will contain an |
655 | unexpanded C<Pod::InteriorSequence> object for each interior-sequence |
656 | encountered. Specifying B<-expand_seq> tells B<parse_text()> to "expand" |
657 | every interior-sequence it sees by invoking the referenced function |
658 | (or named method of the parser object) and using the return value as the |
659 | expanded result. |
660 | |
661 | If a subroutine reference was given, it is invoked as: |
662 | |
663 | &$code_ref( $parser, $sequence ) |
664 | |
665 | and if a method-name was given, it is invoked as: |
666 | |
667 | $parser->method_name( $sequence ) |
668 | |
669 | where C<$parser> is a reference to the parser object, and C<$sequence> |
670 | is a reference to the interior-sequence object. |
671 | [I<NOTE>: If the B<interior_sequence()> method is specified, then it is |
672 | invoked according to the interface specified in L<"interior_sequence()">]. |
673 | |
664bb207 |
674 | =item B<-expand_text> =E<gt> I<code-ref>|I<method-name> |
675 | |
676 | Normally, the parse-tree returned by B<parse_text()> will contain a |
677 | text-string for each contiguous sequence of characters outside of an |
678 | interior-sequence. Specifying B<-expand_text> tells B<parse_text()> to |
679 | "preprocess" every such text-string it sees by invoking the referenced |
680 | function (or named method of the parser object) and using the return value |
681 | as the preprocessed (or "expanded") result. [Note that if the result is |
682 | an interior-sequence, then it will I<not> be expanded as specified by the |
683 | B<-expand_seq> option; Any such recursive expansion needs to be handled by |
684 | the specified callback routine.] |
685 | |
686 | If a subroutine reference was given, it is invoked as: |
687 | |
688 | &$code_ref( $parser, $text, $ptree_node ) |
689 | |
690 | and if a method-name was given, it is invoked as: |
691 | |
692 | $parser->method_name( $text, $ptree_node ) |
693 | |
694 | where C<$parser> is a reference to the parser object, C<$text> is the |
695 | text-string encountered, and C<$ptree_node> is a reference to the current |
696 | node in the parse-tree (usually an interior-sequence object or else the |
697 | top-level node of the parse-tree). |
698 | |
360aca43 |
699 | =item B<-expand_ptree> =E<gt> I<code-ref>|I<method-name> |
700 | |
701 | Rather than returning a C<Pod::ParseTree>, pass the parse-tree as an |
702 | argument to the referenced subroutine (or named method of the parser |
703 | object) and return the result instead of the parse-tree object. |
704 | |
705 | If a subroutine reference was given, it is invoked as: |
706 | |
707 | &$code_ref( $parser, $ptree ) |
708 | |
709 | and if a method-name was given, it is invoked as: |
710 | |
711 | $parser->method_name( $ptree ) |
712 | |
713 | where C<$parser> is a reference to the parser object, and C<$ptree> |
714 | is a reference to the parse-tree object. |
715 | |
716 | =back |
717 | |
718 | =cut |
719 | |
720 | ## This global regex is used to see if the text before a '>' inside |
22641bdf |
721 | ## an interior sequence looks like '-' or '=', but not '--', '==', |
664bb207 |
722 | ## '!=', '$-', '$=' or <<op>>= |
360aca43 |
723 | use vars qw( $ARROW_RE ); |
664bb207 |
724 | $ARROW_RE = join('', qw{ (?: [^-+*/=!&|%^x.<>$]= | [^-$]- )$ }); |
725 | #$ARROW_RE = qr/(?:[^-+*/=!&|%^x.<>$]+=|[^-$]+-)$/; ## 5.005+ only! |
360aca43 |
726 | |
727 | sub parse_text { |
728 | my $self = shift; |
729 | local $_ = ''; |
730 | |
731 | ## Get options and set any defaults |
732 | my %opts = (ref $_[0]) ? %{ shift() } : (); |
733 | my $expand_seq = $opts{'-expand_seq'} || undef; |
664bb207 |
734 | my $expand_text = $opts{'-expand_text'} || undef; |
360aca43 |
735 | my $expand_ptree = $opts{'-expand_ptree'} || undef; |
736 | |
737 | my $text = shift; |
738 | my $line = shift; |
739 | my $file = $self->input_file(); |
740 | my ($cmd, $prev) = ('', ''); |
741 | |
742 | ## Convert method calls into closures, for our convenience |
743 | my $xseq_sub = $expand_seq; |
664bb207 |
744 | my $xtext_sub = $expand_text; |
360aca43 |
745 | my $xptree_sub = $expand_ptree; |
e9fdc7d2 |
746 | if (defined $expand_seq and $expand_seq eq 'interior_sequence') { |
360aca43 |
747 | ## If 'interior_sequence' is the method to use, we have to pass |
748 | ## more than just the sequence object, we also need to pass the |
749 | ## sequence name and text. |
750 | $xseq_sub = sub { |
751 | my ($self, $iseq) = @_; |
752 | my $args = join("", $iseq->parse_tree->children); |
753 | return $self->interior_sequence($iseq->name, $args, $iseq); |
754 | }; |
755 | } |
756 | ref $xseq_sub or $xseq_sub = sub { shift()->$expand_seq(@_) }; |
664bb207 |
757 | ref $xtext_sub or $xtext_sub = sub { shift()->$expand_text(@_) }; |
360aca43 |
758 | ref $xptree_sub or $xptree_sub = sub { shift()->$expand_ptree(@_) }; |
759 | |
760 | ## Keep track of the "current" interior sequence, and maintain a stack |
761 | ## of "in progress" sequences. |
762 | ## |
763 | ## NOTE that we push our own "accumulator" at the very beginning of the |
764 | ## stack. It's really a parse-tree, not a sequence; but it implements |
765 | ## the methods we need so we can use it to gather-up all the sequences |
766 | ## and strings we parse. Thus, by the end of our parsing, it should be |
767 | ## the only thing left on our stack and all we have to do is return it! |
768 | ## |
769 | my $seq = Pod::ParseTree->new(); |
770 | my @seq_stack = ($seq); |
771 | |
772 | ## Iterate over all sequence starts/stops, newlines, & text |
773 | ## (NOTE: split with capturing parens keeps the delimiters) |
774 | $_ = $text; |
775 | for ( split /([A-Z]<|>|\n)/ ) { |
776 | ## Keep track of line count |
777 | ++$line if ($_ eq "\n"); |
778 | ## Look for the beginning of a sequence |
779 | if ( /^([A-Z])(<)$/ ) { |
e9fdc7d2 |
780 | ## Push a new sequence onto the stack of those "in-progress" |
360aca43 |
781 | $seq = Pod::InteriorSequence->new( |
782 | -name => ($cmd = $1), |
783 | -ldelim => $2, -rdelim => '', |
784 | -file => $file, -line => $line |
785 | ); |
786 | (@seq_stack > 1) and $seq->nested($seq_stack[-1]); |
787 | push @seq_stack, $seq; |
788 | } |
789 | ## Look for sequence ending (preclude '->' and '=>' inside C<...>) |
790 | elsif ( (@seq_stack > 1) and |
791 | /^>$/ and ($cmd ne 'C' or $prev !~ /$ARROW_RE/o) ) |
792 | { |
793 | ## End of current sequence, record terminating delimiter |
794 | $seq->rdelim($_); |
795 | ## Pop it off the stack of "in progress" sequences |
796 | pop @seq_stack; |
797 | ## Append result to its parent in current parse tree |
798 | $seq_stack[-1]->append($expand_seq ? &$xseq_sub($self,$seq) : $seq); |
799 | ## Remember the current cmd-name |
800 | $cmd = (@seq_stack > 1) ? $seq_stack[-1]->name : ''; |
801 | } |
664bb207 |
802 | elsif (length) { |
803 | ## In the middle of a sequence, append this text to it, and |
804 | ## dont forget to "expand" it if that's what the caller wanted |
805 | $seq->append($expand_text ? &$xtext_sub($self,$_,$seq) : $_); |
360aca43 |
806 | } |
807 | ## Remember the "current" sequence and the previously seen token |
808 | ($seq, $prev) = ( $seq_stack[-1], $_ ); |
809 | } |
810 | |
811 | ## Handle unterminated sequences |
664bb207 |
812 | my $errorsub = (@seq_stack > 1) ? $self->errorsub() : undef; |
360aca43 |
813 | while (@seq_stack > 1) { |
814 | ($cmd, $file, $line) = ($seq->name, $seq->file_line); |
815 | pop @seq_stack; |
664bb207 |
816 | my $errmsg = "** Unterminated $cmd<...> at $file line $line\n"; |
817 | (ref $errorsub) and &{$errorsub}($errmsg) |
818 | or (defined $errmsg) and $self->$errorsub($errmsg) |
819 | or warn($errmsg); |
360aca43 |
820 | $seq_stack[-1]->append($expand_seq ? &$xseq_sub($self,$seq) : $seq); |
821 | $seq = $seq_stack[-1]; |
822 | } |
823 | |
824 | ## Return the resulting parse-tree |
825 | my $ptree = (pop @seq_stack)->parse_tree; |
826 | return $expand_ptree ? &$xptree_sub($self, $ptree) : $ptree; |
827 | } |
828 | |
829 | ##--------------------------------------------------------------------------- |
830 | |
831 | =head1 B<interpolate()> |
832 | |
833 | $textblock = $parser->interpolate($text, $line_num); |
834 | |
835 | This method translates all text (including any embedded interior sequences) |
836 | in the given text string C<$text> and returns the interpolated result. The |
837 | parameter C<$line_num> is the line number corresponding to the beginning |
838 | of C<$text>. |
839 | |
840 | B<interpolate()> merely invokes a private method to recursively expand |
841 | nested interior sequences in bottom-up order (innermost sequences are |
842 | expanded first). If there is a need to expand nested sequences in |
843 | some alternate order, use B<parse_text> instead. |
844 | |
845 | =cut |
846 | |
847 | sub interpolate { |
848 | my($self, $text, $line_num) = @_; |
849 | my %parse_opts = ( -expand_seq => 'interior_sequence' ); |
850 | my $ptree = $self->parse_text( \%parse_opts, $text, $line_num ); |
851 | return join "", $ptree->children(); |
852 | } |
853 | |
854 | ##--------------------------------------------------------------------------- |
855 | |
856 | =begin __PRIVATE__ |
857 | |
858 | =head1 B<parse_paragraph()> |
859 | |
860 | $parser->parse_paragraph($text, $line_num); |
861 | |
862 | This method takes the text of a POD paragraph to be processed, along |
863 | with its corresponding line number, and invokes the appropriate method |
864 | (one of B<command()>, B<verbatim()>, or B<textblock()>). |
865 | |
664bb207 |
866 | For performance reasons, this method is invoked directly without any |
867 | dynamic lookup; Hence subclasses may I<not> override it! |
360aca43 |
868 | |
869 | =end __PRIVATE__ |
870 | |
871 | =cut |
872 | |
873 | sub parse_paragraph { |
874 | my ($self, $text, $line_num) = @_; |
664bb207 |
875 | local *myData = $self; ## alias to avoid deref-ing overhead |
876 | local *myOpts = ($myData{_PARSEOPTS} ||= {}); ## get parse-options |
360aca43 |
877 | local $_; |
878 | |
664bb207 |
879 | ## See if we want to preprocess nonPOD paragraphs as well as POD ones. |
880 | my $wantNonPods = $myOpts{'-want_nonPODs'} || 0; |
881 | |
882 | ## Perform any desired preprocessing if we wanted it this early |
883 | $wantNonPods and $text = $self->preprocess_paragraph($text, $line_num); |
884 | |
360aca43 |
885 | ## This is the end of a non-empty paragraph |
886 | ## Ignore up until next POD directive if we are cutting |
887 | if ($myData{_CUTTING}) { |
888 | return unless ($text =~ /^={1,2}\S/); |
889 | $myData{_CUTTING} = 0; |
890 | } |
891 | |
892 | ## Now we know this is block of text in a POD section! |
893 | |
894 | ##----------------------------------------------------------------- |
895 | ## This is a hook (hack ;-) for Pod::Select to do its thing without |
896 | ## having to override methods, but also without Pod::Parser assuming |
897 | ## $self is an instance of Pod::Select (if the _SELECTED_SECTIONS |
898 | ## field exists then we assume there is an is_selected() method for |
899 | ## us to invoke (calling $self->can('is_selected') could verify this |
900 | ## but that is more overhead than I want to incur) |
901 | ##----------------------------------------------------------------- |
902 | |
903 | ## Ignore this block if it isnt in one of the selected sections |
904 | if (exists $myData{_SELECTED_SECTIONS}) { |
905 | $self->is_selected($text) or return ($myData{_CUTTING} = 1); |
906 | } |
907 | |
664bb207 |
908 | ## If we havent already, perform any desired preprocessing and |
909 | ## then re-check the "cutting" state |
910 | unless ($wantNonPods) { |
911 | $text = $self->preprocess_paragraph($text, $line_num); |
912 | return 1 unless ((defined $text) and (length $text)); |
913 | return 1 if ($myData{_CUTTING}); |
914 | } |
360aca43 |
915 | |
916 | ## Look for one of the three types of paragraphs |
917 | my ($pfx, $cmd, $arg, $sep) = ('', '', '', ''); |
918 | my $pod_para = undef; |
919 | if ($text =~ /^(={1,2})(?=\S)/) { |
920 | ## Looks like a command paragraph. Capture the command prefix used |
921 | ## ("=" or "=="), as well as the command-name, its paragraph text, |
922 | ## and whatever sequence of characters was used to separate them |
923 | $pfx = $1; |
924 | $_ = substr($text, length $pfx); |
925 | $sep = /(\s+)(?=\S)/ ? $1 : ''; |
926 | ($cmd, $text) = split(" ", $_, 2); |
927 | ## If this is a "cut" directive then we dont need to do anything |
928 | ## except return to "cutting" mode. |
929 | if ($cmd eq 'cut') { |
930 | $myData{_CUTTING} = 1; |
664bb207 |
931 | return unless $myOpts{'-process_cut_cmd'}; |
360aca43 |
932 | } |
933 | } |
934 | ## Save the attributes indicating how the command was specified. |
935 | $pod_para = new Pod::Paragraph( |
936 | -name => $cmd, |
937 | -text => $text, |
938 | -prefix => $pfx, |
939 | -separator => $sep, |
940 | -file => $myData{_INFILE}, |
941 | -line => $line_num |
942 | ); |
943 | # ## Invoke appropriate callbacks |
944 | # if (exists $myData{_CALLBACKS}) { |
945 | # ## Look through the callback list, invoke callbacks, |
946 | # ## then see if we need to do the default actions |
947 | # ## (invoke_callbacks will return true if we do). |
948 | # return 1 unless $self->invoke_callbacks($cmd, $text, $line_num, $pod_para); |
949 | # } |
950 | if (length $cmd) { |
951 | ## A command paragraph |
952 | $self->command($cmd, $text, $line_num, $pod_para); |
953 | } |
954 | elsif ($text =~ /^\s+/) { |
955 | ## Indented text - must be a verbatim paragraph |
956 | $self->verbatim($text, $line_num, $pod_para); |
957 | } |
958 | else { |
959 | ## Looks like an ordinary block of text |
960 | $self->textblock($text, $line_num, $pod_para); |
961 | } |
962 | return 1; |
963 | } |
964 | |
965 | ##--------------------------------------------------------------------------- |
966 | |
967 | =head1 B<parse_from_filehandle()> |
968 | |
969 | $parser->parse_from_filehandle($in_fh,$out_fh); |
970 | |
971 | This method takes an input filehandle (which is assumed to already be |
972 | opened for reading) and reads the entire input stream looking for blocks |
973 | (paragraphs) of POD documentation to be processed. If no first argument |
974 | is given the default input filehandle C<STDIN> is used. |
975 | |
976 | The C<$in_fh> parameter may be any object that provides a B<getline()> |
977 | method to retrieve a single line of input text (hence, an appropriate |
978 | wrapper object could be used to parse PODs from a single string or an |
979 | array of strings). |
980 | |
981 | Using C<$in_fh-E<gt>getline()>, input is read line-by-line and assembled |
982 | into paragraphs or "blocks" (which are separated by lines containing |
983 | nothing but whitespace). For each block of POD documentation |
984 | encountered it will invoke a method to parse the given paragraph. |
985 | |
986 | If a second argument is given then it should correspond to a filehandle where |
987 | output should be sent (otherwise the default output filehandle is |
988 | C<STDOUT> if no output filehandle is currently in use). |
989 | |
990 | B<NOTE:> For performance reasons, this method caches the input stream at |
991 | the top of the stack in a local variable. Any attempts by clients to |
992 | change the stack contents during processing when in the midst executing |
993 | of this method I<will not affect> the input stream used by the current |
994 | invocation of this method. |
995 | |
996 | This method does I<not> usually need to be overridden by subclasses. |
997 | |
998 | =cut |
999 | |
1000 | sub parse_from_filehandle { |
1001 | my $self = shift; |
1002 | my %opts = (ref $_[0] eq 'HASH') ? %{ shift() } : (); |
1003 | my ($in_fh, $out_fh) = @_; |
22641bdf |
1004 | $in_fh = \*STDIN unless ($in_fh); |
360aca43 |
1005 | local $_; |
1006 | |
1007 | ## Put this stream at the top of the stack and do beginning-of-input |
1008 | ## processing. NOTE that $in_fh might be reset during this process. |
1009 | my $topstream = $self->_push_input_stream($in_fh, $out_fh); |
1010 | (exists $opts{-cutting}) and $self->cutting( $opts{-cutting} ); |
1011 | |
1012 | ## Initialize line/paragraph |
1013 | my ($textline, $paragraph) = ('', ''); |
1014 | my ($nlines, $plines) = (0, 0); |
1015 | |
1016 | ## Use <$fh> instead of $fh->getline where possible (for speed) |
1017 | $_ = ref $in_fh; |
1018 | my $tied_fh = (/^(?:GLOB|FileHandle|IO::\w+)$/ or tied $in_fh); |
1019 | |
1020 | ## Read paragraphs line-by-line |
1021 | while (defined ($textline = $tied_fh ? <$in_fh> : $in_fh->getline)) { |
1022 | $textline = $self->preprocess_line($textline, ++$nlines); |
1023 | next unless ((defined $textline) && (length $textline)); |
1024 | $_ = $paragraph; ## save previous contents |
1025 | |
1026 | if ((! length $paragraph) && ($textline =~ /^==/)) { |
1027 | ## '==' denotes a one-line command paragraph |
1028 | $paragraph = $textline; |
1029 | $plines = 1; |
1030 | $textline = ''; |
1031 | } else { |
1032 | ## Append this line to the current paragraph |
1033 | $paragraph .= $textline; |
1034 | ++$plines; |
1035 | } |
1036 | |
1037 | ## See of this line is blank and ends the current paragraph. |
1038 | ## If it isnt, then keep iterating until it is. |
1039 | next unless (($textline =~ /^\s*$/) && (length $paragraph)); |
1040 | |
1041 | ## Now process the paragraph |
1042 | parse_paragraph($self, $paragraph, ($nlines - $plines) + 1); |
1043 | $paragraph = ''; |
1044 | $plines = 0; |
1045 | } |
1046 | ## Dont forget about the last paragraph in the file |
1047 | if (length $paragraph) { |
1048 | parse_paragraph($self, $paragraph, ($nlines - $plines) + 1) |
1049 | } |
1050 | |
1051 | ## Now pop the input stream off the top of the input stack. |
1052 | $self->_pop_input_stream(); |
1053 | } |
1054 | |
1055 | ##--------------------------------------------------------------------------- |
1056 | |
1057 | =head1 B<parse_from_file()> |
1058 | |
1059 | $parser->parse_from_file($filename,$outfile); |
1060 | |
1061 | This method takes a filename and does the following: |
1062 | |
1063 | =over 2 |
1064 | |
1065 | =item * |
1066 | |
1067 | opens the input and output files for reading |
1068 | (creating the appropriate filehandles) |
1069 | |
1070 | =item * |
1071 | |
1072 | invokes the B<parse_from_filehandle()> method passing it the |
1073 | corresponding input and output filehandles. |
1074 | |
1075 | =item * |
1076 | |
1077 | closes the input and output files. |
1078 | |
1079 | =back |
1080 | |
1081 | If the special input filename "-" or "<&STDIN" is given then the STDIN |
1082 | filehandle is used for input (and no open or close is performed). If no |
1083 | input filename is specified then "-" is implied. |
1084 | |
1085 | If a second argument is given then it should be the name of the desired |
1086 | output file. If the special output filename "-" or ">&STDOUT" is given |
1087 | then the STDOUT filehandle is used for output (and no open or close is |
1088 | performed). If the special output filename ">&STDERR" is given then the |
1089 | STDERR filehandle is used for output (and no open or close is |
1090 | performed). If no output filehandle is currently in use and no output |
1091 | filename is specified, then "-" is implied. |
1092 | |
1093 | This method does I<not> usually need to be overridden by subclasses. |
1094 | |
1095 | =cut |
1096 | |
1097 | sub parse_from_file { |
1098 | my $self = shift; |
1099 | my %opts = (ref $_[0] eq 'HASH') ? %{ shift() } : (); |
1100 | my ($infile, $outfile) = @_; |
1101 | my ($in_fh, $out_fh) = (undef, undef); |
1102 | my ($close_input, $close_output) = (0, 0); |
1103 | local *myData = $self; |
1104 | local $_; |
1105 | |
1106 | ## Is $infile a filename or a (possibly implied) filehandle |
1107 | $infile = '-' unless ((defined $infile) && (length $infile)); |
1108 | if (($infile eq '-') || ($infile =~ /^<&(STDIN|0)$/i)) { |
1109 | ## Not a filename, just a string implying STDIN |
1110 | $myData{_INFILE} = "<standard input>"; |
1111 | $in_fh = \*STDIN; |
1112 | } |
1113 | elsif (ref $infile) { |
1114 | ## Must be a filehandle-ref (or else assume its a ref to an object |
1115 | ## that supports the common IO read operations). |
1116 | $myData{_INFILE} = ${$infile}; |
1117 | $in_fh = $infile; |
1118 | } |
1119 | else { |
1120 | ## We have a filename, open it for reading |
1121 | $myData{_INFILE} = $infile; |
1122 | $in_fh = FileHandle->new("< $infile") or |
1123 | croak "Can't open $infile for reading: $!\n"; |
1124 | $close_input = 1; |
1125 | } |
1126 | |
1127 | ## NOTE: we need to be *very* careful when "defaulting" the output |
1128 | ## file. We only want to use a default if this is the beginning of |
1129 | ## the entire document (but *not* if this is an included file). We |
1130 | ## determine this by seeing if the input stream stack has been set-up |
1131 | ## already |
1132 | ## |
1133 | unless ((defined $outfile) && (length $outfile)) { |
1134 | (defined $myData{_TOP_STREAM}) && ($out_fh = $myData{_OUTPUT}) |
1135 | || ($outfile = '-'); |
1136 | } |
1137 | ## Is $outfile a filename or a (possibly implied) filehandle |
1138 | if ((defined $outfile) && (length $outfile)) { |
1139 | if (($outfile eq '-') || ($outfile =~ /^>&?(?:STDOUT|1)$/i)) { |
1140 | ## Not a filename, just a string implying STDOUT |
1141 | $myData{_OUTFILE} = "<standard output>"; |
1142 | $out_fh = \*STDOUT; |
1143 | } |
1144 | elsif ($outfile =~ /^>&(STDERR|2)$/i) { |
1145 | ## Not a filename, just a string implying STDERR |
1146 | $myData{_OUTFILE} = "<standard error>"; |
1147 | $out_fh = \*STDERR; |
1148 | } |
1149 | elsif (ref $outfile) { |
1150 | ## Must be a filehandle-ref (or else assume its a ref to an |
1151 | ## object that supports the common IO write operations). |
1152 | $myData{_OUTFILE} = ${$outfile};; |
1153 | $out_fh = $outfile; |
1154 | } |
1155 | else { |
1156 | ## We have a filename, open it for writing |
1157 | $myData{_OUTFILE} = $outfile; |
1158 | $out_fh = FileHandle->new("> $outfile") or |
1159 | croak "Can't open $outfile for writing: $!\n"; |
1160 | $close_output = 1; |
1161 | } |
1162 | } |
1163 | |
1164 | ## Whew! That was a lot of work to set up reasonably/robust behavior |
1165 | ## in the case of a non-filename for reading and writing. Now we just |
1166 | ## have to parse the input and close the handles when we're finished. |
1167 | $self->parse_from_filehandle(\%opts, $in_fh, $out_fh); |
1168 | |
1169 | $close_input and |
1170 | close($in_fh) || croak "Can't close $infile after reading: $!\n"; |
1171 | $close_output and |
1172 | close($out_fh) || croak "Can't close $outfile after writing: $!\n"; |
1173 | } |
1174 | |
1175 | ############################################################################# |
1176 | |
1177 | =head1 ACCESSOR METHODS |
1178 | |
1179 | Clients of B<Pod::Parser> should use the following methods to access |
1180 | instance data fields: |
1181 | |
1182 | =cut |
1183 | |
1184 | ##--------------------------------------------------------------------------- |
1185 | |
664bb207 |
1186 | =head1 B<errorsub()> |
1187 | |
1188 | $parser->errorsub("method_name"); |
1189 | $parser->errorsub(\&warn_user); |
1190 | $parser->errorsub(sub { print STDERR, @_ }); |
1191 | |
1192 | Specifies the method or subroutine to use when printing error messages |
1193 | about POD syntax. The supplied method/subroutine I<must> return TRUE upon |
1194 | successful printing of the message. If C<undef> is given, then the B<warn> |
1195 | builtin is used to issue error messages (this is the default behavior). |
1196 | |
1197 | my $errorsub = $parser->errorsub() |
1198 | my $errmsg = "This is an error message!\n" |
1199 | (ref $errorsub) and &{$errorsub}($errmsg) |
1200 | or (defined $errmsg) and $parser->$errorsub($errmsg) |
1201 | or warn($errmsg); |
1202 | |
1203 | Returns a method name, or else a reference to the user-supplied subroutine |
1204 | used to print error messages. Returns C<undef> if the B<warn> builtin |
1205 | is used to issue error messages (this is the default behavior). |
1206 | |
1207 | =cut |
1208 | |
1209 | sub errorsub { |
1210 | return (@_ > 1) ? ($_[0]->{_ERRORSUB} = $_[1]) : $_[0]->{_ERRORSUB}; |
1211 | } |
1212 | |
1213 | ##--------------------------------------------------------------------------- |
1214 | |
360aca43 |
1215 | =head1 B<cutting()> |
1216 | |
1217 | $boolean = $parser->cutting(); |
1218 | |
1219 | Returns the current C<cutting> state: a boolean-valued scalar which |
1220 | evaluates to true if text from the input file is currently being "cut" |
1221 | (meaning it is I<not> considered part of the POD document). |
1222 | |
1223 | $parser->cutting($boolean); |
1224 | |
1225 | Sets the current C<cutting> state to the given value and returns the |
1226 | result. |
1227 | |
1228 | =cut |
1229 | |
1230 | sub cutting { |
1231 | return (@_ > 1) ? ($_[0]->{_CUTTING} = $_[1]) : $_[0]->{_CUTTING}; |
1232 | } |
1233 | |
1234 | ##--------------------------------------------------------------------------- |
1235 | |
664bb207 |
1236 | ##--------------------------------------------------------------------------- |
1237 | |
1238 | =head1 B<parseopts()> |
1239 | |
1240 | When invoked with no additional arguments, B<parseopts> returns a hashtable |
1241 | of all the current parsing options. |
1242 | |
1243 | ## See if we are parsing non-POD sections as well as POD ones |
1244 | my %opts = $parser->parseopts(); |
1245 | $opts{'-want_nonPODs}' and print "-want_nonPODs\n"; |
1246 | |
1247 | When invoked using a single string, B<parseopts> treats the string as the |
1248 | name of a parse-option and returns its corresponding value if it exists |
1249 | (returns C<undef> if it doesn't). |
1250 | |
1251 | ## Did we ask to see '=cut' paragraphs? |
1252 | my $want_cut = $parser->parseopts('-process_cut_cmd'); |
1253 | $want_cut and print "-process_cut_cmd\n"; |
1254 | |
1255 | When invoked with multiple arguments, B<parseopts> treats them as |
1256 | key/value pairs and the specified parse-option names are set to the |
1257 | given values. Any unspecified parse-options are unaffected. |
1258 | |
1259 | ## Set them back to the default |
1260 | $parser->parseopts(-process_cut_cmd => 0); |
1261 | |
1262 | When passed a single hash-ref, B<parseopts> uses that hash to completely |
1263 | reset the existing parse-options, all previous parse-option values |
1264 | are lost. |
1265 | |
1266 | ## Reset all options to default |
1267 | $parser->parseopts( { } ); |
1268 | |
1269 | See L<"PARSING OPTIONS"> for more for the name and meaning of each |
1270 | parse-option currently recognized. |
1271 | |
1272 | =cut |
1273 | |
1274 | sub parseopts { |
1275 | local *myData = shift; |
1276 | local *myOpts = ($myData{_PARSEOPTS} ||= {}); |
1277 | return %myOpts if (@_ == 0); |
1278 | if (@_ == 1) { |
1279 | local $_ = shift; |
1280 | return ref($_) ? $myData{_PARSEOPTS} = $_ : $myOpts{$_}; |
1281 | } |
1282 | my @newOpts = (%myOpts, @_); |
1283 | $myData{_PARSEOPTS} = { @newOpts }; |
1284 | } |
1285 | |
1286 | ##--------------------------------------------------------------------------- |
1287 | |
360aca43 |
1288 | =head1 B<output_file()> |
1289 | |
1290 | $fname = $parser->output_file(); |
1291 | |
1292 | Returns the name of the output file being written. |
1293 | |
1294 | =cut |
1295 | |
1296 | sub output_file { |
1297 | return $_[0]->{_OUTFILE}; |
1298 | } |
1299 | |
1300 | ##--------------------------------------------------------------------------- |
1301 | |
1302 | =head1 B<output_handle()> |
1303 | |
1304 | $fhandle = $parser->output_handle(); |
1305 | |
1306 | Returns the output filehandle object. |
1307 | |
1308 | =cut |
1309 | |
1310 | sub output_handle { |
1311 | return $_[0]->{_OUTPUT}; |
1312 | } |
1313 | |
1314 | ##--------------------------------------------------------------------------- |
1315 | |
1316 | =head1 B<input_file()> |
1317 | |
1318 | $fname = $parser->input_file(); |
1319 | |
1320 | Returns the name of the input file being read. |
1321 | |
1322 | =cut |
1323 | |
1324 | sub input_file { |
1325 | return $_[0]->{_INFILE}; |
1326 | } |
1327 | |
1328 | ##--------------------------------------------------------------------------- |
1329 | |
1330 | =head1 B<input_handle()> |
1331 | |
1332 | $fhandle = $parser->input_handle(); |
1333 | |
1334 | Returns the current input filehandle object. |
1335 | |
1336 | =cut |
1337 | |
1338 | sub input_handle { |
1339 | return $_[0]->{_INPUT}; |
1340 | } |
1341 | |
1342 | ##--------------------------------------------------------------------------- |
1343 | |
1344 | =begin __PRIVATE__ |
1345 | |
1346 | =head1 B<input_streams()> |
1347 | |
1348 | $listref = $parser->input_streams(); |
1349 | |
1350 | Returns a reference to an array which corresponds to the stack of all |
1351 | the input streams that are currently in the middle of being parsed. |
1352 | |
1353 | While parsing an input stream, it is possible to invoke |
1354 | B<parse_from_file()> or B<parse_from_filehandle()> to parse a new input |
1355 | stream and then return to parsing the previous input stream. Each input |
1356 | stream to be parsed is pushed onto the end of this input stack |
1357 | before any of its input is read. The input stream that is currently |
1358 | being parsed is always at the end (or top) of the input stack. When an |
1359 | input stream has been exhausted, it is popped off the end of the |
1360 | input stack. |
1361 | |
1362 | Each element on this input stack is a reference to C<Pod::InputSource> |
1363 | object. Please see L<Pod::InputObjects> for more details. |
1364 | |
1365 | This method might be invoked when printing diagnostic messages, for example, |
1366 | to obtain the name and line number of the all input files that are currently |
1367 | being processed. |
1368 | |
1369 | =end __PRIVATE__ |
1370 | |
1371 | =cut |
1372 | |
1373 | sub input_streams { |
1374 | return $_[0]->{_INPUT_STREAMS}; |
1375 | } |
1376 | |
1377 | ##--------------------------------------------------------------------------- |
1378 | |
1379 | =begin __PRIVATE__ |
1380 | |
1381 | =head1 B<top_stream()> |
1382 | |
1383 | $hashref = $parser->top_stream(); |
1384 | |
1385 | Returns a reference to the hash-table that represents the element |
1386 | that is currently at the top (end) of the input stream stack |
1387 | (see L<"input_streams()">). The return value will be the C<undef> |
1388 | if the input stack is empty. |
1389 | |
1390 | This method might be used when printing diagnostic messages, for example, |
1391 | to obtain the name and line number of the current input file. |
1392 | |
1393 | =end __PRIVATE__ |
1394 | |
1395 | =cut |
1396 | |
1397 | sub top_stream { |
1398 | return $_[0]->{_TOP_STREAM} || undef; |
1399 | } |
1400 | |
1401 | ############################################################################# |
1402 | |
1403 | =head1 PRIVATE METHODS AND DATA |
1404 | |
1405 | B<Pod::Parser> makes use of several internal methods and data fields |
1406 | which clients should not need to see or use. For the sake of avoiding |
1407 | name collisions for client data and methods, these methods and fields |
1408 | are briefly discussed here. Determined hackers may obtain further |
1409 | information about them by reading the B<Pod::Parser> source code. |
1410 | |
1411 | Private data fields are stored in the hash-object whose reference is |
1412 | returned by the B<new()> constructor for this class. The names of all |
1413 | private methods and data-fields used by B<Pod::Parser> begin with a |
1414 | prefix of "_" and match the regular expression C</^_\w+$/>. |
1415 | |
1416 | =cut |
1417 | |
1418 | ##--------------------------------------------------------------------------- |
1419 | |
1420 | =begin _PRIVATE_ |
1421 | |
1422 | =head1 B<_push_input_stream()> |
1423 | |
1424 | $hashref = $parser->_push_input_stream($in_fh,$out_fh); |
1425 | |
1426 | This method will push the given input stream on the input stack and |
1427 | perform any necessary beginning-of-document or beginning-of-file |
1428 | processing. The argument C<$in_fh> is the input stream filehandle to |
1429 | push, and C<$out_fh> is the corresponding output filehandle to use (if |
1430 | it is not given or is undefined, then the current output stream is used, |
1431 | which defaults to standard output if it doesnt exist yet). |
1432 | |
1433 | The value returned will be reference to the hash-table that represents |
1434 | the new top of the input stream stack. I<Please Note> that it is |
1435 | possible for this method to use default values for the input and output |
1436 | file handles. If this happens, you will need to look at the C<INPUT> |
1437 | and C<OUTPUT> instance data members to determine their new values. |
1438 | |
1439 | =end _PRIVATE_ |
1440 | |
1441 | =cut |
1442 | |
1443 | sub _push_input_stream { |
1444 | my ($self, $in_fh, $out_fh) = @_; |
1445 | local *myData = $self; |
1446 | |
1447 | ## Initialize stuff for the entire document if this is *not* |
1448 | ## an included file. |
1449 | ## |
1450 | ## NOTE: we need to be *very* careful when "defaulting" the output |
1451 | ## filehandle. We only want to use a default value if this is the |
1452 | ## beginning of the entire document (but *not* if this is an included |
1453 | ## file). |
1454 | unless (defined $myData{_TOP_STREAM}) { |
1455 | $out_fh = \*STDOUT unless (defined $out_fh); |
1456 | $myData{_CUTTING} = 1; ## current "cutting" state |
1457 | $myData{_INPUT_STREAMS} = []; ## stack of all input streams |
1458 | } |
1459 | |
1460 | ## Initialize input indicators |
1461 | $myData{_OUTFILE} = '(unknown)' unless (defined $myData{_OUTFILE}); |
1462 | $myData{_OUTPUT} = $out_fh if (defined $out_fh); |
1463 | $in_fh = \*STDIN unless (defined $in_fh); |
1464 | $myData{_INFILE} = '(unknown)' unless (defined $myData{_INFILE}); |
1465 | $myData{_INPUT} = $in_fh; |
1466 | my $input_top = $myData{_TOP_STREAM} |
1467 | = new Pod::InputSource( |
1468 | -name => $myData{_INFILE}, |
1469 | -handle => $in_fh, |
1470 | -was_cutting => $myData{_CUTTING} |
1471 | ); |
1472 | local *input_stack = $myData{_INPUT_STREAMS}; |
1473 | push(@input_stack, $input_top); |
1474 | |
1475 | ## Perform beginning-of-document and/or beginning-of-input processing |
1476 | $self->begin_pod() if (@input_stack == 1); |
1477 | $self->begin_input(); |
1478 | |
1479 | return $input_top; |
1480 | } |
1481 | |
1482 | ##--------------------------------------------------------------------------- |
1483 | |
1484 | =begin _PRIVATE_ |
1485 | |
1486 | =head1 B<_pop_input_stream()> |
1487 | |
1488 | $hashref = $parser->_pop_input_stream(); |
1489 | |
1490 | This takes no arguments. It will perform any necessary end-of-file or |
1491 | end-of-document processing and then pop the current input stream from |
1492 | the top of the input stack. |
1493 | |
1494 | The value returned will be reference to the hash-table that represents |
1495 | the new top of the input stream stack. |
1496 | |
1497 | =end _PRIVATE_ |
1498 | |
1499 | =cut |
1500 | |
1501 | sub _pop_input_stream { |
1502 | my ($self) = @_; |
1503 | local *myData = $self; |
1504 | local *input_stack = $myData{_INPUT_STREAMS}; |
1505 | |
1506 | ## Perform end-of-input and/or end-of-document processing |
1507 | $self->end_input() if (@input_stack > 0); |
1508 | $self->end_pod() if (@input_stack == 1); |
1509 | |
1510 | ## Restore cutting state to whatever it was before we started |
1511 | ## parsing this file. |
1512 | my $old_top = pop(@input_stack); |
1513 | $myData{_CUTTING} = $old_top->was_cutting(); |
1514 | |
1515 | ## Dont forget to reset the input indicators |
1516 | my $input_top = undef; |
1517 | if (@input_stack > 0) { |
1518 | $input_top = $myData{_TOP_STREAM} = $input_stack[-1]; |
1519 | $myData{_INFILE} = $input_top->name(); |
1520 | $myData{_INPUT} = $input_top->handle(); |
1521 | } else { |
1522 | delete $myData{_TOP_STREAM}; |
1523 | delete $myData{_INPUT_STREAMS}; |
1524 | } |
1525 | |
1526 | return $input_top; |
1527 | } |
1528 | |
1529 | ############################################################################# |
1530 | |
664bb207 |
1531 | =head1 TREE-BASED PARSING |
1532 | |
1533 | If straightforward stream-based parsing wont meet your needs (as is |
1534 | likely the case for tasks such as translating PODs into structured |
1535 | markup languages like HTML and XML) then you may need to take the |
1536 | tree-based approach. Rather than doing everything in one pass and |
1537 | calling the B<interpolate()> method to expand sequences into text, it |
1538 | may be desirable to instead create a parse-tree using the B<parse_text()> |
1539 | method to return a tree-like structure which may contain an ordered list |
1540 | list of children (each of which may be a text-string, or a similar |
1541 | tree-like structure). |
1542 | |
1543 | Pay special attention to L<"METHODS FOR PARSING AND PROCESSING"> and |
1544 | to the objects described in L<Pod::InputObjects>. The former describes |
1545 | the gory details and parameters for how to customize and extend the |
1546 | parsing behavior of B<Pod::Parser>. B<Pod::InputObjects> provides |
1547 | several objects that may all be used interchangeably as parse-trees. The |
1548 | most obvious one is the B<Pod::ParseTree> object. It defines the basic |
1549 | interface and functionality that all things trying to be a POD parse-tree |
1550 | should do. A B<Pod::ParseTree> is defined such that each "node" may be a |
1551 | text-string, or a reference to another parse-tree. Each B<Pod::Paragraph> |
1552 | object and each B<Pod::InteriorSequence> object also supports the basic |
1553 | parse-tree interface. |
1554 | |
1555 | The B<parse_text()> method takes a given paragraph of text, and |
1556 | returns a parse-tree that contains one or more children, each of which |
1557 | may be a text-string, or an InteriorSequence object. There are also |
1558 | callback-options that may be passed to B<parse_text()> to customize |
1559 | the way it expands or transforms interior-sequences, as well as the |
1560 | returned result. These callbacks can be used to create a parse-tree |
1561 | with custom-made objects (which may or may not support the parse-tree |
1562 | interface, depending on how you choose to do it). |
1563 | |
1564 | If you wish to turn an entire POD document into a parse-tree, that process |
1565 | is fairly straightforward. The B<parse_text()> method is the key to doing |
1566 | this successfully. Every paragraph-callback (i.e. the polymorphic methods |
1567 | for B<command()>, B<verbatim()>, and B<textblock()> paragraphs) takes |
1568 | a B<Pod::Paragraph> object as an argument. Each paragraph object has a |
1569 | B<parse_tree()> method that can be used to get or set a corresponding |
1570 | parse-tree. So for each of those paragraph-callback methods, simply call |
1571 | B<parse_text()> with the options you desire, and then use the returned |
1572 | parse-tree to assign to the given paragraph object. |
1573 | |
1574 | That gives you a parse-tree for each paragraph - so now all you need is |
1575 | an ordered list of paragraphs. You can maintain that yourself as a data |
1576 | element in the object/hash. The most straightforward way would be simply |
1577 | to use an array-ref, with the desired set of custom "options" for each |
1578 | invocation of B<parse_text>. Let's assume the desired option-set is |
1579 | given by the hash C<%options>. Then we might do something like the |
1580 | following: |
1581 | |
1582 | package MyPodParserTree; |
1583 | |
1584 | @ISA = qw( Pod::Parser ); |
1585 | |
1586 | ... |
1587 | |
1588 | sub begin_pod { |
1589 | my $self = shift; |
1590 | $self->{'-paragraphs'} = []; ## initialize paragraph list |
1591 | } |
1592 | |
1593 | sub command { |
1594 | my ($parser, $command, $paragraph, $line_num, $pod_para) = @_; |
1595 | my $ptree = $parser->parse_text({%options}, $paragraph, ...); |
1596 | $pod_para->parse_tree( $ptree ); |
1597 | push @{ $self->{'-paragraphs'} }, $pod_para; |
1598 | } |
1599 | |
1600 | sub verbatim { |
1601 | my ($parser, $paragraph, $line_num, $pod_para) = @_; |
1602 | push @{ $self->{'-paragraphs'} }, $pod_para; |
1603 | } |
1604 | |
1605 | sub textblock { |
1606 | my ($parser, $paragraph, $line_num, $pod_para) = @_; |
1607 | my $ptree = $parser->parse_text({%options}, $paragraph, ...); |
1608 | $pod_para->parse_tree( $ptree ); |
1609 | push @{ $self->{'-paragraphs'} }, $pod_para; |
1610 | } |
1611 | |
1612 | ... |
1613 | |
1614 | package main; |
1615 | ... |
1616 | my $parser = new MyPodParserTree(...); |
1617 | $parser->parse_from_file(...); |
1618 | my $paragraphs_ref = $parser->{'-paragraphs'}; |
1619 | |
1620 | Of course, in this module-author's humble opinion, I'd be more inclined to |
1621 | use the existing B<Pod::ParseTree> object than a simple array. That way |
1622 | everything in it, paragraphs and sequences, all respond to the same core |
1623 | interface for all parse-tree nodes. The result would look something like: |
1624 | |
1625 | package MyPodParserTree2; |
1626 | |
1627 | ... |
1628 | |
1629 | sub begin_pod { |
1630 | my $self = shift; |
1631 | $self->{'-ptree'} = new Pod::ParseTree; ## initialize parse-tree |
1632 | } |
1633 | |
1634 | sub parse_tree { |
1635 | ## convenience method to get/set the parse-tree for the entire POD |
1636 | (@_ > 1) and $_[0]->{'-ptree'} = $_[1]; |
1637 | return $_[0]->{'-ptree'}; |
1638 | } |
1639 | |
1640 | sub command { |
1641 | my ($parser, $command, $paragraph, $line_num, $pod_para) = @_; |
1642 | my $ptree = $parser->parse_text({<<options>>}, $paragraph, ...); |
1643 | $pod_para->parse_tree( $ptree ); |
1644 | $parser->parse_tree()->append( $pod_para ); |
1645 | } |
1646 | |
1647 | sub verbatim { |
1648 | my ($parser, $paragraph, $line_num, $pod_para) = @_; |
1649 | $parser->parse_tree()->append( $pod_para ); |
1650 | } |
1651 | |
1652 | sub textblock { |
1653 | my ($parser, $paragraph, $line_num, $pod_para) = @_; |
1654 | my $ptree = $parser->parse_text({<<options>>}, $paragraph, ...); |
1655 | $pod_para->parse_tree( $ptree ); |
1656 | $parser->parse_tree()->append( $pod_para ); |
1657 | } |
1658 | |
1659 | ... |
1660 | |
1661 | package main; |
1662 | ... |
1663 | my $parser = new MyPodParserTree2(...); |
1664 | $parser->parse_from_file(...); |
1665 | my $ptree = $parser->parse_tree; |
1666 | ... |
1667 | |
1668 | Now you have the entire POD document as one great big parse-tree. You |
1669 | can even use the B<-expand_seq> option to B<parse_text> to insert |
1670 | whole different kinds of objects. Just don't expect B<Pod::Parser> |
1671 | to know what to do with them after that. That will need to be in your |
1672 | code. Or, alternatively, you can insert any object you like so long as |
1673 | it conforms to the B<Pod::ParseTree> interface. |
1674 | |
1675 | One could use this to create subclasses of B<Pod::Paragraphs> and |
1676 | B<Pod::InteriorSequences> for specific commands (or to create your own |
1677 | custom node-types in the parse-tree) and add some kind of B<emit()> |
1678 | method to each custom node/subclass object in the tree. Then all you'd |
1679 | need to do is recursively walk the tree in the desired order, processing |
1680 | the children (most likely from left to right) by formatting them if |
1681 | they are text-strings, or by calling their B<emit()> method if they |
1682 | are objects/references. |
1683 | |
360aca43 |
1684 | =head1 SEE ALSO |
1685 | |
1686 | L<Pod::InputObjects>, L<Pod::Select> |
1687 | |
1688 | B<Pod::InputObjects> defines POD input objects corresponding to |
1689 | command paragraphs, parse-trees, and interior-sequences. |
1690 | |
1691 | B<Pod::Select> is a subclass of B<Pod::Parser> which provides the ability |
1692 | to selectively include and/or exclude sections of a POD document from being |
1693 | translated based upon the current heading, subheading, subsubheading, etc. |
1694 | |
1695 | =for __PRIVATE__ |
1696 | B<Pod::Callbacks> is a subclass of B<Pod::Parser> which gives its users |
1697 | the ability the employ I<callback functions> instead of, or in addition |
1698 | to, overriding methods of the base class. |
1699 | |
1700 | =for __PRIVATE__ |
1701 | B<Pod::Select> and B<Pod::Callbacks> do not override any |
1702 | methods nor do they define any new methods with the same name. Because |
1703 | of this, they may I<both> be used (in combination) as a base class of |
1704 | the same subclass in order to combine their functionality without |
1705 | causing any namespace clashes due to multiple inheritance. |
1706 | |
1707 | =head1 AUTHOR |
1708 | |
1709 | Brad Appleton E<lt>bradapp@enteract.comE<gt> |
1710 | |
1711 | Based on code for B<Pod::Text> written by |
1712 | Tom Christiansen E<lt>tchrist@mox.perl.comE<gt> |
1713 | |
1714 | =cut |
1715 | |
1716 | 1; |