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Gisle Aas


HTML::PullParser - Alternative HTML::Parser interface


 use HTML::PullParser;

 $p = HTML::PullParser->new(file => "index.html",
                            start => 'event, tagname, @attr',
                            end   => 'event, tagname',
                            ignore_elements => [qw(script style)],
                           ) || die "Can't open: $!";
     #...do something with $token


The HTML::PullParser is an alternative interface to the HTML::Parser class. It basically turns the HTML::Parser inside out. You associate a file (or any IO::Handle object or string) with the parser at construction time and then repeatedly call $parser->get_token to obtain the tags and text found in the parsed document.

The following methods are provided:

$p = HTML::PullParser->new( file => $file, %options )
$p = HTML::PullParser->new( doc => \$doc, %options )

A HTML::PullParser can be made to parse from either a file or a literal document based on whether the file or doc option is passed to the parser's constructor.

The file passed in can either be a file name or a file handle object. If a file name is passed, and it can't be opened for reading, then the constructor will return an undefined value and $! will tell you why it failed. Otherwise the argument is taken to be some object that the HTML::PullParser can read() from when it needs more data. The stream will be read() until EOF, but not closed.

A doc can be passed plain or as a reference to a scalar. If a reference is passed then the value of this scalar should not be changed before all tokens have been extracted.

Next the information to be returned for the different token types must be set up. This is done by simply associating an argspec (as defined in HTML::Parser) with the events you have an interest in. For instance, if you want start tokens to be reported as the string 'S' followed by the tagname and the attributes you might pass an start-option like this:

   $p = HTML::PullParser->new(
          doc   => $document_to_parse,
          start => '"S", tagname, @attr',
          end   => '"E", tagname',

At last other HTML::Parser options, like ignore_tags, and unbroken_text, can be passed in. Note that you should not use the event_h options to set up parser handlers. That would confuse the inner logic of HTML::PullParser.

$token = $p->get_token

This method will return the next token found in the HTML document, or undef at the end of the document. The token is returned as an array reference. The content of this array match the argspec set up during HTML::PullParser construction.

$p->unget_token( @tokens )

If you find out you have read too many tokens you can push them back, so that they are returned again the next time $p->get_token is called.


The 'eg/hform' script shows how we might parse the form section of HTML::Documents using HTML::PullParser.


HTML::Parser, HTML::TokeParser


Copyright 1998-2001 Gisle Aas.


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