Bring Pod::Simple up to 3.09 as on CPAN.

[p5sagit/p5-mst-13.2.git] / cpan / Pod-Simple / lib / Pod / Simple.pod

=head1 NAME

Pod::Simple - framework for parsing Pod

=head1 SYNOPSIS

 TODO

=head1 DESCRIPTION

Pod::Simple is a Perl library for parsing text in the Pod ("plain old
documentation") markup language that is typically used for writing
documentation for Perl and for Perl modules. The Pod format is explained
in the L<perlpod|perlpod> man page; the most common formatter is called
"perldoc".

Pod formatters can use Pod::Simple to parse Pod documents into produce
renderings of them in plain ASCII, in HTML, or in any number of other
formats. Typically, such formatters will be subclasses of Pod::Simple,
and so they will inherit its methods, like C<parse_file>.

If you're reading this document just because you have a Pod-processing
subclass that you want to use, this document (plus the documentation for
the subclass) is probably all you'll need to read.

If you're reading this document because you want to write a formatter
subclass, continue reading this document, and then read
L<Pod::Simple::Subclassing>, and then possibly even read L<perlpodspec>
(some of which is for parser-writers, but much of which is notes to
formatter-writers).


=head1 MAIN METHODS



=over

=item C<< $parser = I<SomeClass>->new(); >>

This returns a new parser object, where I<C<SomeClass>> is a subclass
of Pod::Simple.

=item C<< $parser->output_fh( *OUT ); >>

This sets the filehandle that C<$parser>'s output will be written to.
You can pass C<*STDOUT>, otherwise you should probably do something
like this:

    my $outfile = "output.txt";
    open TXTOUT, ">$outfile" or die "Can't write to $outfile: $!";
    $parser->output_fh(*TXTOUT);

...before you call one of the C<< $parser->parse_I<whatever> >> methods.

=item C<< $parser->output_string( \$somestring ); >>

This sets the string that C<$parser>'s output will be sent to,
instead of any filehandle.


=item C<< $parser->parse_file( I<$some_filename> ); >>

=item C<< $parser->parse_file( *INPUT_FH ); >>

This reads the Pod content of the file (or filehandle) that you specify,
and processes it with that C<$parser> object, according to however
C<$parser>'s class works, and according to whatever parser options you
have set up for this C<$parser> object.

=item C<< $parser->parse_string_document( I<$all_content> ); >>

This works just like C<parse_file> except that it reads the Pod
content not from a file, but from a string that you have already
in memory.

=item C<< $parser->parse_lines( I<...@lines...>, undef ); >>

This processes the lines in C<@lines> (where each list item must be a
defined value, and must contain exactly one line of content -- so no
items like C<"foo\nbar"> are allowed).  The final C<undef> is used to
indicate the end of document being parsed.

The other C<parser_I<whatever>> methods are meant to be called only once
per C<$parser> object; but C<parse_lines> can be called as many times per
C<$parser> object as you want, as long as the last call (and only
the last call) ends with an C<undef> value.


=item C<< $parser->content_seen >>

This returns true only if there has been any real content seen
for this document.


=item C<< I<SomeClass>->filter( I<$filename> ); >>

=item C<< I<SomeClass>->filter( I<*INPUT_FH> ); >>

=item C<< I<SomeClass>->filter( I<\$document_content> ); >>

This is a shortcut method for creating a new parser object, setting the
output handle to STDOUT, and then processing the specified file (or
filehandle, or in-memory document). This is handy for one-liners like
this:

  perl -MPod::Simple::Text -e "Pod::Simple::Text->filter('thingy.pod')"

=back



=head1 SECONDARY METHODS

Some of these methods might be of interest to general users, as
well as of interest to formatter-writers.

Note that the general pattern here is that the accessor-methods
read the attribute's value with C<< $value = $parser->I<attribute> >>
and set the attribute's value with
C<< $parser->I<attribute>(I<newvalue>) >>.  For each accessor, I typically
only mention one syntax or another, based on which I think you are actually
most likely to use.


=over

=item C<< $parser->no_whining( I<SOMEVALUE> ) >>

If you set this attribute to a true value, you will suppress the
parser's complaints about irregularities in the Pod coding. By default,
this attribute's value is false, meaning that irregularities will
be reported.

Note that turning this attribute to true won't suppress one or two kinds
of complaints about rarely occurring unrecoverable errors.


=item C<< $parser->no_errata_section( I<SOMEVALUE> ) >>

If you set this attribute to a true value, you will stop the parser from
generating a "POD ERRORS" section at the end of the document. By
default, this attribute's value is false, meaning that an errata section
will be generated, as necessary.


=item C<< $parser->complain_stderr( I<SOMEVALUE> ) >>

If you set this attribute to a true value, it will send reports of
parsing errors to STDERR. By default, this attribute's value is false,
meaning that no output is sent to STDERR.

Setting C<complain_stderr> also sets C<no_errata_section>.


=item C<< $parser->source_filename >>

This returns the filename that this parser object was set to read from.


=item C<< $parser->doc_has_started >>

This returns true if C<$parser> has read from a source, and has seen
Pod content in it.


=item C<< $parser->source_dead >>

This returns true if C<$parser> has read from a source, and come to the
end of that source.

=item C<< $parser->strip_verbatim_indent( I<SOMEVALUE> ) >>

The perlpod spec for a Verbatim paragraph is "It should be reproduced
exactly...", which means that the whitespace you've used to indent your
verbatim blocks will be preserved in the output. This can be annoying for
outputs such as HTML, where that whitespace will remain in front of every
line. It's an unfortunate case where syntax is turned into semantics.

If the POD your parsing adheres to a consistent indentation policy, you can
have such indentation stripped from the beginning of every line of your
verbatim blocks. This method tells Pod::Simple what to strip. For two-space
indents, you'd use:

  $parser->strip_verbatim_indent('  ');

For tab indents, you'd use a tab character:

  $parser->strip_verbatim_indent("\t");

If the POD is inconsistent about the indentation of verbatim blocks, but you
have figured out a heuristic to determine how much a particular verbatim block
is indented, you can pass a code reference instead. The code reference will be
executed with one argument, an array reference of all the lines in the
verbatim block, and should return the value to be stripped from each line. For
example, if you decide that you're fine to use the first line of the verbatim
block to set the standard for indentation of the rest of the block, you can
look at the first line and return the appropriate value, like so:

  $new->strip_verbatim_indent(sub {
      my $lines = shift;
      (my $indent = $lines->[0]) =~ s/\S.*//;
      return $indent;
  });

If you'd rather treat each line individually, you can do that, too, by just
transforming them in-place in the code reference and returning C<undef>. Say
that you don't want I<any> lines indented. You can do something like this:

  $new->strip_verbatim_indent(sub {
      my $lines = shift;
      sub { s/^\s+// for @{ $lines },
      return undef;
  });

=back

=head1 CAVEATS

This is just a beta release -- there are a good number of things still
left to do.  Notably, support for EBCDIC platforms is still half-done,
an untested.


=head1 SEE ALSO

L<Pod::Simple::Subclassing>

L<perlpod|perlpod>

L<perlpodspec|perlpodspec>

L<Pod::Escapes|Pod::Escapes>

L<perldoc>


=head1 COPYRIGHT AND DISCLAIMERS

Copyright (c) 2002 Sean M. Burke.  All rights reserved.

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.

=head1 AUTHOR

Original author: Sean M. Burke C<sburke@cpan.org>

Maintained by: 

=over

=item * Allison Randal C<allison@perl.org>

=item * Hans Dieter Pearcey C<hdp@cpan.org>

=back

=cut