1Pod::Simple(3) User Contributed Perl Documentation Pod::Simple(3)
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6 Pod::Simple - framework for parsing Pod
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9 TODO
10
12 Pod::Simple is a Perl library for parsing text in the Pod ("plain old
13 documentation") markup language that is typically used for writing
14 documentation for Perl and for Perl modules. The Pod format is
15 explained in perlpod; the most common formatter is called "perldoc".
16 Be sure to read "ENCODING" if your Pod contains non-ASCII characters.
18 Pod formatters can use Pod::Simple to parse Pod documents and render
20 them into plain text, HTML, or any number of other formats. Typically,
21 such formatters will be subclasses of Pod::Simple, and so they will
22 inherit its methods, like "parse_file".
23 If you're reading this document just because you have a Pod-processing
25 subclass that you want to use, this document (plus the documentation
26 for the subclass) is probably all you need to read.
27 If you're reading this document because you want to write a formatter
29 subclass, continue reading it and then read Pod::Simple::Subclassing,
30 and then possibly even read perlpodspec (some of which is for parser-
31 writers, but much of which is notes to formatter-writers).
32
34 "$parser = SomeClass->new();"
35 This returns a new parser object, where "SomeClass" is a subclass
36 of Pod::Simple.
37 "$parser->output_fh( *OUT );"
39 This sets the filehandle that $parser's output will be written to.
40 You can pass *STDOUT or *STDERR, otherwise you should probably do
41 something like this:
42 my $outfile = "output.txt";
44 open TXTOUT, ">$outfile" or die "Can't write to $outfile: $!";
45 $parser->output_fh(*TXTOUT);
46 ...before you call one of the "$parser->parse_whatever" methods.
48 "$parser->output_string( \$somestring );"
50 This sets the string that $parser's output will be sent to, instead
51 of any filehandle.
52 "$parser->parse_file( $some_filename );"
54 "$parser->parse_file( *INPUT_FH );"
55 This reads the Pod content of the file (or filehandle) that you
56 specify, and processes it with that $parser object, according to
57 however $parser's class works, and according to whatever parser
58 options you have set up for this $parser object.
59 "$parser->parse_string_document( $all_content );"
61 This works just like "parse_file" except that it reads the Pod
62 content not from a file, but from a string that you have already in
63 memory.
64 "$parser->parse_lines( ...@lines..., undef );"
66 This processes the lines in @lines (where each list item must be a
67 defined value, and must contain exactly one line of content -- so
68 no items like "foo\nbar" are allowed). The final "undef" is used
69 to indicate the end of document being parsed.
70 The other "parser_whatever" methods are meant to be called only
72 once per $parser object; but "parse_lines" can be called as many
73 times per $parser object as you want, as long as the last call (and
74 only the last call) ends with an "undef" value.
75 "$parser->content_seen"
77 This returns true only if there has been any real content seen for
78 this document. Returns false in cases where the document contains
79 content, but does not make use of any Pod markup.
80 "SomeClass->filter( $filename );"
82 "SomeClass->filter( *INPUT_FH );"
83 "SomeClass->filter( \$document_content );"
84 This is a shortcut method for creating a new parser object, setting
85 the output handle to STDOUT, and then processing the specified file
86 (or filehandle, or in-memory document). This is handy for one-
87 liners like this:
88 perl -MPod::Simple::Text -e "Pod::Simple::Text->filter('thingy.pod')"
90
92 Some of these methods might be of interest to general users, as well as
93 of interest to formatter-writers.
94 Note that the general pattern here is that the accessor-methods read
96 the attribute's value with "$value = $parser->attribute" and set the
97 attribute's value with "$parser->attribute(newvalue)". For each
98 accessor, I typically only mention one syntax or another, based on
99 which I think you are actually most likely to use.
100 "$parser->parse_characters( SOMEVALUE )"
102 The Pod parser normally expects to read octets and to convert those
103 octets to characters based on the "=encoding" declaration in the
104 Pod source. Set this option to a true value to indicate that the
105 Pod source is already a Perl character stream. This tells the
106 parser to ignore any "=encoding" command and to skip all the code
107 paths involving decoding octets.
108 "$parser->no_whining( SOMEVALUE )"
110 If you set this attribute to a true value, you will suppress the
111 parser's complaints about irregularities in the Pod coding. By
112 default, this attribute's value is false, meaning that
113 irregularities will be reported.
114 Note that turning this attribute to true won't suppress one or two
116 kinds of complaints about rarely occurring unrecoverable errors.
117 "$parser->no_errata_section( SOMEVALUE )"
119 If you set this attribute to a true value, you will stop the parser
120 from generating a "POD ERRORS" section at the end of the document.
121 By default, this attribute's value is false, meaning that an errata
122 section will be generated, as necessary.
123 "$parser->complain_stderr( SOMEVALUE )"
125 If you set this attribute to a true value, it will send reports of
126 parsing errors to STDERR. By default, this attribute's value is
127 false, meaning that no output is sent to STDERR.
128 Setting "complain_stderr" also sets "no_errata_section".
130 "$parser->source_filename"
132 This returns the filename that this parser object was set to read
133 from.
134 "$parser->doc_has_started"
136 This returns true if $parser has read from a source, and has seen
137 Pod content in it.
138 "$parser->source_dead"
140 This returns true if $parser has read from a source, and come to
141 the end of that source.
142 "$parser->strip_verbatim_indent( SOMEVALUE )"
144 The perlpod spec for a Verbatim paragraph is "It should be
145 reproduced exactly...", which means that the whitespace you've used
146 to indent your verbatim blocks will be preserved in the output.
147 This can be annoying for outputs such as HTML, where that
148 whitespace will remain in front of every line. It's an unfortunate
149 case where syntax is turned into semantics.
150 If the POD you're parsing adheres to a consistent indentation
152 policy, you can have such indentation stripped from the beginning
153 of every line of your verbatim blocks. This method tells
154 Pod::Simple what to strip. For two-space indents, you'd use:
155 $parser->strip_verbatim_indent(' ');
157 For tab indents, you'd use a tab character:
159 $parser->strip_verbatim_indent("\t");
161 If the POD is inconsistent about the indentation of verbatim
163 blocks, but you have figured out a heuristic to determine how much
164 a particular verbatim block is indented, you can pass a code
165 reference instead. The code reference will be executed with one
166 argument, an array reference of all the lines in the verbatim
167 block, and should return the value to be stripped from each line.
168 For example, if you decide that you're fine to use the first line
169 of the verbatim block to set the standard for indentation of the
170 rest of the block, you can look at the first line and return the
171 appropriate value, like so:
172 $new->strip_verbatim_indent(sub {
174 my $lines = shift;
175 (my $indent = $lines->[0]) =~ s/\S.*//;
176 return $indent;
177 });
178 If you'd rather treat each line individually, you can do that, too,
180 by just transforming them in-place in the code reference and
181 returning "undef". Say that you don't want any lines indented. You
182 can do something like this:
183 $new->strip_verbatim_indent(sub {
185 my $lines = shift;
186 sub { s/^\s+// for @{ $lines },
187 return undef;
188 });
189
191 "$parser->abandon_output_fh()"
192 Cancel output to the file handle. Any POD read by the $parser is
193 not effected.
194 "$parser->abandon_output_string()"
196 Cancel output to the output string. Any POD read by the $parser is
197 not effected.
198 "$parser->accept_code( @codes )"
200 Alias for accept_codes.
201 "$parser->accept_codes( @codes )"
203 Allows $parser to accept a list of "Formatting Codes" in perlpod.
204 This can be used to implement user-defined codes.
205 "$parser->accept_directive_as_data( @directives )"
207 Allows $parser to accept a list of directives for data paragraphs.
208 A directive is the label of a "Command Paragraph" in perlpod. A
209 data paragraph is one delimited by "=begin/=for/=end" directives.
210 This can be used to implement user-defined directives.
211 "$parser->accept_directive_as_processed( @directives )"
213 Allows $parser to accept a list of directives for processed
214 paragraphs. A directive is the label of a "Command Paragraph" in
215 perlpod. A processed paragraph is also known as "Ordinary
216 Paragraph" in perlpod. This can be used to implement user-defined
217 directives.
218 "$parser->accept_directive_as_verbatim( @directives )"
220 Allows $parser to accept a list of directives for "Verbatim
221 Paragraph" in perlpod. A directive is the label of a "Command
222 Paragraph" in perlpod. This can be used to implement user-defined
223 directives.
224 "$parser->accept_target( @targets )"
226 Alias for accept_targets.
227 "$parser->accept_target_as_text( @targets )"
229 Alias for accept_targets_as_text.
230 "$parser->accept_targets( @targets )"
232 Accepts targets for "=begin/=for/=end" sections of the POD.
233 "$parser->accept_targets_as_text( @targets )"
235 Accepts targets for "=begin/=for/=end" sections that should be
236 parsed as POD. For details, see "About Data Paragraphs" in
237 perlpodspec.
238 "$parser->any_errata_seen()"
240 Used to check if any errata was seen.
241 Example:
243 die "too many errors\n" if $parser->any_errata_seen();
245 "$parser->errata_seen()"
247 Returns a hash reference of all errata seen, both whines and
248 screams. The hash reference's keys are the line number and the
249 value is an array reference of the errors for that line.
250 Example:
252 if ( $parser->any_errata_seen() ) {
254 $logger->log( $parser->errata_seen() );
255 }
256 "$parser->detected_encoding()"
258 Return the encoding corresponding to "=encoding", but only if the
259 encoding was recognized and handled.
260 "$parser->encoding()"
262 Return encoding of the document, even if the encoding is not
263 correctly handled.
264 "$parser->parse_from_file( $source, $to )"
266 Parses from $source file to $to file. Similar to "parse_from_file"
267 in Pod::Parser.
268 "$parser->scream( @error_messages )"
270 Log an error that can't be ignored.
271 "$parser->unaccept_code( @codes )"
273 Alias for unaccept_codes.
274 "$parser->unaccept_codes( @codes )"
276 Removes @codes as valid codes for the parse.
277 "$parser->unaccept_directive( @directives )"
279 Alias for unaccept_directives.
280 "$parser->unaccept_directives( @directives )"
282 Removes @directives as valid directives for the parse.
283 "$parser->unaccept_target( @targets )"
285 Alias for unaccept_targets.
286 "$parser->unaccept_targets( @targets )"
288 Removes @targets as valid targets for the parse.
289 "$parser->version_report()"
291 Returns a string describing the version.
292 "$parser->whine( @error_messages )"
294 Log an error unless "$parser->no_whining( TRUE );".
295
297 The Pod::Simple parser expects to read octets. The parser will decode
298 the octets into Perl's internal character string representation using
299 the value of the "=encoding" declaration in the POD source.
300 If the POD source does not include an "=encoding" declaration, the
302 parser will attempt to guess the encoding (selecting one of UTF-8 or CP
303 1252) by examining the first non-ASCII bytes and applying the heuristic
304 described in perlpodspec. (If the POD source contains only ASCII
305 bytes, the encoding is assumed to be ASCII.)
306 If you set the "parse_characters" option to a true value the parser
308 will expect characters rather than octets; will ignore any "=encoding";
309 and will make no attempt to decode the input.
310
312 Pod::Simple::Subclassing
313 perlpod
315 perlpodspec
317 Pod::Escapes
319 perldoc
321
323 Questions or discussion about POD and Pod::Simple should be sent to the
324 pod-people@perl.org mail list. Send an empty email to
325 pod-people-subscribe@perl.org to subscribe.
326 This module is managed in an open GitHub repository,
328 <https://github.com/perl-pod/pod-simple/>. Feel free to fork and
329 contribute, or to clone <git://github.com/perl-pod/pod-simple.git> and
330 send patches!
331 Patches against Pod::Simple are welcome. Please send bug reports to
333 <bug-pod-simple@rt.cpan.org>.
334
336 Copyright (c) 2002 Sean M. Burke.
337 This library is free software; you can redistribute it and/or modify it
339 under the same terms as Perl itself.
340 This program is distributed in the hope that it will be useful, but
342 without any warranty; without even the implied warranty of
343 merchantability or fitness for a particular purpose.
344
346 Pod::Simple was created by Sean M. Burke <sburke@cpan.org>. But don't
347 bother him, he's retired.
348 Pod::Simple is maintained by:
350 · Allison Randal "allison@perl.org"
352 · Hans Dieter Pearcey "hdp@cpan.org"
354 · David E. Wheeler "dwheeler@cpan.org"
356 Documentation has been contributed by:
358 · Gabor Szabo "szabgab@gmail.com"
360 · Shawn H Corey "SHCOREY at cpan.org"
362perl v5.26.3 2016-11-29 Pod::Simple(3)