Pod::Simple::PullParser

Section: Perl Programmers Reference Guide (3perl)
Updated: 2019-04-20
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NAME

Pod::Simple::PullParser -- a pull-parser interface to parsing Pod

SYNOPSIS

 my $parser = SomePodProcessor->new;
 $parser->set_source( "whatever.pod" );
 $parser->run;

Or:

 my $parser = SomePodProcessor->new;
 $parser->set_source( $some_filehandle_object );
 $parser->run;

Or:

 my $parser = SomePodProcessor->new;
 $parser->set_source( \$document_source );
 $parser->run;

Or:

 my $parser = SomePodProcessor->new;
 $parser->set_source( \@document_lines );
 $parser->run;

And elsewhere:

 require 5;
 package SomePodProcessor;
 use strict;
 use base qw(Pod::Simple::PullParser);

 sub run {
   my $self = shift;
  Token:
   while(my $token = $self->get_token) {
     ...process each token...
   }
 }

DESCRIPTION

This class is for using Pod::Simple to build a Pod processor --- but one that uses an interface based on a stream of token objects, instead of based on events.

This is a subclass of Pod::Simple and inherits all its methods.

A subclass of Pod::Simple::PullParser should define a "run" method that calls "$token = $parser->get_token" to pull tokens.

See the source for Pod::Simple::RTF for an example of a formatter that uses Pod::Simple::PullParser.

METHODS

my $token = $parser->get_token: This returns the next token object (which will be of a subclass of Pod::Simple::PullParserToken), or undef if the parser-stream has hit the end of the document.
$parser->unget_token( $token )
$parser->unget_token( $token1, $token2, ... ): This restores the token object(s) to the front of the parser stream.

The source has to be set before you can parse anything. The lowest-level way is to call "set_source":

$parser->set_source( $filename )
$parser->set_source( $filehandle_object )
$parser->set_source( \$document_source )
$parser->set_source( \@document_lines )

Or you can call these methods, which Pod::Simple::PullParser has defined to work just like Pod::Simple's same-named methods:

$parser->parse_file(...)
$parser->parse_string_document(...)
$parser->filter(...)
$parser->parse_from_file(...)

For those to work, the Pod-processing subclass of Pod::Simple::PullParser has to have defined a $parser->run method --- so it is advised that all Pod::Simple::PullParser subclasses do so. See the Synopsis above, or the source for Pod::Simple::RTF.

Authors of formatter subclasses might find these methods useful to call on a parser object that you haven't started pulling tokens from yet:

my $title_string = $parser->get_title

This tries to get the title string out of $parser, by getting some tokens, and scanning them for the title, and then ungetting them so that you can process the token-stream from the beginning.

For example, suppose you have a document that starts out:

  =head1 NAME

  Hoo::Boy::Wowza -- Stuff B<wow> yeah!

$parser->get_title on that document will return ``Hoo::Boy::Wowza --- Stuff wow yeah!''. If the document starts with:

  =head1 Name

  Hoo::Boy::W00t -- Stuff B<w00t> yeah!

Then you'll need to pass the "nocase" option in order to recognize ``Name'':

  $parser->get_title(nocase => 1);

In cases where get_title can't find the title, it will return empty-string ("").

my $title_string = $parser->get_short_title

This is just like get_title, except that it returns just the modulename, if the title seems to be of the form ``SomeModuleName --- description''.

For example, suppose you have a document that starts out:

  =head1 NAME

  Hoo::Boy::Wowza -- Stuff B<wow> yeah!

then $parser->get_short_title on that document will return ``Hoo::Boy::Wowza''.

But if the document starts out:

  =head1 NAME

  Hooboy, stuff B<wow> yeah!

then $parser->get_short_title on that document will return ``Hooboy, stuff wow yeah!''. If the document starts with:

  =head1 Name

  Hoo::Boy::W00t -- Stuff B<w00t> yeah!

Then you'll need to pass the "nocase" option in order to recognize ``Name'':

  $parser->get_short_title(nocase => 1);

If the title can't be found, then get_short_title returns empty-string ("").

$author_name = $parser->get_author

This works like get_title except that it returns the contents of the ``=head1 AUTHOR\n\nParagraph...\n'' section, assuming that that section isn't terribly long. To recognize a ``=head1 Author\n\nParagraph\n'' section, pass the "nocase" option:

  $parser->get_author(nocase => 1);

(This method tolerates ``AUTHORS'' instead of ``AUTHOR'' too.)

$description_name = $parser->get_description

This works like get_title except that it returns the contents of the ``=head1 DESCRIPTION\n\nParagraph...\n'' section, assuming that that section isn't terribly long. To recognize a ``=head1 Description\n\nParagraph\n'' section, pass the "nocase" option:

  $parser->get_description(nocase => 1);

$version_block = $parser->get_version

This works like get_title except that it returns the contents of the ``=head1 VERSION\n\n[BIG BLOCK]\n'' block. Note that this does NOT return the module's $VERSION!! To recognize a ``=head1 Version\n\n[BIG BLOCK]\n'' section, pass the "nocase" option:

  $parser->get_version(nocase => 1);

NOTE

You don't actually have to define a "run" method. If you're writing a Pod-formatter class, you should define a "run" just so that users can call "parse_file" etc, but you don't have to.

And if you're not writing a formatter class, but are instead just writing a program that does something simple with a Pod::PullParser object (and not an object of a subclass), then there's no reason to bother subclassing to add a "run" method.

SUPPORT

Questions or discussion about POD and Pod::Simple should be sent to the pod-people@perl.org mail list. Send an empty email to pod-people-subscribe@perl.org to subscribe.

This module is managed in an open GitHub repository, <https://github.com/perl-pod/pod-simple/>. Feel free to fork and contribute, or to clone <git://github.com/perl-pod/pod-simple.git> and send patches!

Patches against Pod::Simple are welcome. Please send bug reports to <bug-pod-simple@rt.cpan.org>.

COPYRIGHT AND DISCLAIMERS

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose.

AUTHOR

Pod::Simple was created by Sean M. Burke <sburke@cpan.org>. But don't bother him, he's retired.

Pod::Simple is maintained by:

•: Allison Randal "allison@perl.org"
•: Hans Dieter Pearcey "hdp@cpan.org"
•: David E. Wheeler "dwheeler@cpan.org"