Author image Ricardo SIGNES 😄
and 3 contributors

NAME

Pod::Eventual - read a POD document as a series of trivial events

VERSION

version 0.094002

SYNOPSIS

  package Your::Pod::Parser;
  use base 'Pod::Eventual';

  sub handle_event {
    my ($self, $event) = @_;

    print Dumper($event);
  }

DESCRIPTION

POD is a pretty simple format to write, but it can be a big pain to deal with reading it and doing anything useful with it. Most existing POD parsers care about semantics, like whether a =item occurred after an =over but before a back, figuring out how to link a L<>, and other things like that.

Pod::Eventual is much less ambitious and much more stupid. Fortunately, stupid is often better. (That's what I keep telling myself, anyway.)

Pod::Eventual reads line-based input and produces events describing each POD paragraph or directive it finds. Once complete events are immediately passed to the handle_event method. This method should be implemented by Pod::Eventual subclasses. If it isn't, Pod::Eventual's own handle_event will be called, and will raise an exception.

PERL VERSION

This library should run on perls released even a long time ago. It should work on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.

METHODS

read_handle

  Pod::Eventual->read_handle($io_handle, \%arg);

This method iterates through the lines of a handle, producing events and calling the handle_event method.

The only valid argument in %arg (for now) is in_pod, which indicates whether we should assume that we are parsing pod when we start parsing the file. By default, this is false.

This is useful to behave differently when reading a .pm or .pod file.

Important: the handle is expected to have an encoding layer so that it will return text, not bytes, on reads.

read_file

This behaves just like read_handle, but expects a filename rather than a handle. The file will be assumed to be UTF-8 encoded.

read_string

This behaves just like read_handle, but expects a string containing POD text rather than a handle.

handle_event

This method is called each time Pod::Eventual finishes scanning for a new POD event. It must be implemented by a subclass or it will raise an exception.

handle_nonpod

This method is called each time a non-POD segment is seen -- that is, lines after =cut and before another command.

If unimplemented by a subclass, it does nothing by default.

handle_blank

This method is called at the end of a sequence of one or more blank lines.

If unimplemented by a subclass, it does nothing by default.

EVENTS

There are four kinds of events that Pod::Eventual will produce. All are represented as hash references.

Command Events

These events represent commands -- those things that start with an equals sign in the first column. Here are some examples of POD and the event that would be produced.

A simple header:

  =head1 NAME

  { type => 'command', command => 'head1', content => "NAME\n", start_line => 4 }

Notice that the content includes the trailing newline. That's to maintain similarity with this possibly-surprising case:

  =for HTML
  We're actually still in the command event, here.

  {
    type    => 'command',
    command => 'for',
    content => "HTML\nWe're actually still in the command event, here.\n",
    start_line => 8,
  }

Pod::Eventual does not care what the command is. It doesn't keep track of what it's seen or whether you've used a command that isn't defined. The only special case is =cut, which is never more than one line.

  =cut
  We are no longer parsing POD when this line is read.

  {
    type    => 'command',
    command => 'cut',
    content => "\n",
    start_line => 15,
  }

Waiving this special case may be an option in the future.

Text Events

A text event is just a paragraph of text, beginning after one or more empty lines and running until the next empty line (or =cut). In Perl 5's standard usage of Pod, text content that begins with whitespace is a "verbatim" paragraph, and text content that begins with non-whitespace is an "ordinary" paragraph.

Pod::Eventual doesn't care.

Text events look like this:

  {
    type    => 'text',
    content => "a string of text ending with a\n",
    start_line =>  16,
  }

Blank events

These events represent blank lines (or many blank lines) within a Pod section.

Blank events look like this:

  {
    type    => 'blank',
    content => "\n\n\n\n",
    start_line => 21,
  }

Non-Pod events

These events represent non-Pod segments of the input.

Non-Pod events look like this:

  {
    type    => 'nonpod',
    content => "#!/usr/bin/perl\nuse strict;\n\nuse Acme::ProgressBar\n\n",
    start_line => 1,
  }

AUTHOR

Ricardo SIGNES <rjbs@semiotic.systems>

CONTRIBUTORS

  • Hans Dieter Pearcey <hdp@weftsoar.net>

  • Philippe Bruhat (BooK) <book@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2021 by Ricardo SIGNES.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.