XML/TokeParser version 0.05

XML/TokeParser version 0.05
=======================

INSTALLATION

To install this module type the following:

perl Makefile.PL
make
make test
make install

NAME
XML::TokeParser - Simplified interface to XML::Parser

SYNOPSIS
use XML::TokeParser;
#
#parse from file
my $p = XML::TokeParser->new('file.xml')
#
#parse from open handle
open IN, 'file.xml' or die $!;
my $p = XML::TokeParser->new( \*IN, Noempty => 1 );
#
#parse literal text
my $text = '<tag xmlns="http://www.omsdev.com">text</tag>';
my $p = XML::TokeParser->new( \$text, Namespaces => 1 );
#
#read next token
my $token = $p->get_token();
#
#skip to <title> and read text
$p->get_tag('title');
$p->get_text();
#
#read text of next <para>, ignoring any internal markup
$p->get_tag('para');
$p->get_trimmed_text('/para');
#
#process <para> if interesting text
$t = $p->get_tag('para');
$p->begin_saving($t);
if ( $p->get_trimmed_text('/para') =~ /interesting stuff/ ) {
$p->restore_saved();
process_para($p);
}

DESCRIPTION
XML::TokeParser provides a procedural ("pull mode") interface to
XML::Parser in much the same way that Gisle Aas' HTML::TokeParser
provides a procedural interface to HTML::Parser. XML::TokeParser splits
its XML input up into "tokens," each corresponding to an XML::Parser
event.

A token is a bless'd reference to an array whose first element is an
event-type string and whose last element is the literal text of the XML
input that generated the event, with intermediate elements varying
according to the event type.

Each token is an *object* of type XML::TokeParser::Token. Read
"XML::TokeParser::Token" to learn what methods are available for
inspecting the token, and retrieving data from it.

METHODS
$p = XML::TokeParser->new($input, [options])
Creates a new parser, specifying the input source and any options.
If $input is a string, it is the name of the file to parse. If
$input is a reference to a string, that string is the actual text to
parse. If $input is a reference to a typeglob or an IO::Handle
object corresponding to an open file or socket, the text read from
the handle will be parsed.

Options are name=>value pairs and can be any of the following:

Namespaces
If set to a true value, namespace processing is enabled.

ParseParamEnt
This option is passed on to the underlying XML::Parser object;
see that module's documentation for details.

Noempty
If set to a true value, text tokens consisting of only
whitespace (such as those created by indentation and line breaks
in between tags) will be ignored.

Latin
If set to a true value, all text other than the literal text
elements of tokens will be translated into the ISO 8859-1
(Latin-1) character encoding rather than the normal UTF-8
encoding.

Catalog
The value is the URI of a catalog file used to resolve PUBLIC
and SYSTEM identifiers. See XML::Catalog for details.

$token = $p->get_token()
Returns the next token, as an array reference, from the input.
Returns undef if there are no remaining tokens.

$p->unget_token($token,...)
Pushes tokens back so they will be re-read. Useful if you've read
one or more tokens too far. Correctly handles "partial" tokens
returned by get_tag().

$token = $p->get_tag( [$token] )
If no argument given, skips tokens until the next start tag or end
tag token. If an argument is given, skips tokens until the start tag
or end tag (if the argument begins with '/') for the named element.
The returned token does not include an event type code; its first
element is the element name, prefixed by a '/' if the token is for
an end tag.

$text = $p->get_text( [$token] )
If no argument given, returns the text at the current position, or
an empty string if the next token is not a 'T' token. If an argument
is given, gathers up all text between the current position and the
specified start or end tag, stripping out any intervening tags (much
like the way a typical Web browser deals with unknown tags).

$text = $p->get_trimmed_text( [$token] )
Like get_text(), but deletes any leading or trailing whitespaces and
collapses multiple whitespace (including newlines) into single
spaces.

$p->begin_saving( [$token] )
Causes subsequent calls to get_token(), get_tag(), get_text(), and
get_trimmed_text() to save the returned tokens. In conjunction with
restore_saved(), allows you to "back up" within a token stream. If
an argument is supplied, it is placed at the beginning of the list
of saved tokens (useful because you often won't know you want to
begin saving until you've already read the first token you want
saved).

$p->restore_saved()
Pushes all the tokens saved by begin_saving() back onto the token
stream. Stops saving tokens. To cancel saving without backing up,
call begin_saving() and restore_saved() in succession.

XML::TokeParser::Token
A token is a blessed array reference, that you acquire using
"$p->get_token" or "$p->get_tag", and that might look like:

["S", $tag, $attr, $attrseq, $raw]
["E", $tag, $raw]
["T", $text, $raw]
["C", $text, $raw]
["PI", $target, $data, $raw]

If you don't like remembering array indices (you're a real programmer),
you may access the attributes of a token like:

"$t->tag", "$t->attr", "$t->attrseq", "$t->raw", "$t->text",
"$t->target", "$t->data".

****Please note that this may change in the future, where as there will
be 4 token types, XML::TokeParser::Token::StartTag ....

What kind of token is it?

To find out, inspect your token using any of these is_* methods (1 ==
true, 0 == false, d'oh):

is_text
is_comment
is_pi which is short for is_process_instruction
is_start_tag
is_end_tag
is_tag

What's that token made of? To retrieve data from your token, use any of
the following methods, depending on the kind of token you have:

target
only for process instructions

data
only for process instructions

raw for all tokens

attr
only for start tags, returns a hashref ( "print "#link ",
""$t->attr""->{href}" ).

my $attrseq = $t->attrseq
only for start tags, returns an array ref of the keys found in
"$t->attr" in the order they originally appeared in.

my $tagname = $t->tag
only for tags ( "print "opening ", ""$t->tag"" if
""$t->is_start_tag" ).

my $text = $token->text
only for tokens of type text and comment

Here's more detailed info about the tokens.

Start tag
The token has five elements: 'S', the element's name, a reference to
a hash of attribute values keyed by attribute names, a reference to
an array of attribute names in the order in which they appeared in
the tag, and the literal text.

End tag
The token has three elements: 'E', the element's name, and the
literal text.

Character data (text)
The token has three elements: 'T', the parsed text, and the literal
text. All contiguous runs of text are gathered into single tokens;
there will never be two 'T' tokens in a row.

Comment
The token has three elements: 'C', the parsed text of the comment,
and the literal text.

Processing instruction
The token has four elements: 'PI', the target, the data, and the
literal text.

The literal text includes any markup delimiters (pointy brackets,
<![CDATA[, etc.), entity references, and numeric character references
and is in the XML document's original character encoding. All other text
is in UTF-8 (unless the Latin option is set, in which case it's in
ISO-8859-1) regardless of the original encoding, and all entity and
character references are expanded.

If the Namespaces option is set, element and attribute names are
prefixed by their (possibly empty) namespace URIs enclosed in curly
brackets and xmlns:* attributes do not appear in 'S' tokens.

DIFFERENCES FROM HTML::TokeParser
Uses a true XML parser rather than a modified HTML parser.

Text and comment tokens include extracted text as well as literal text.

PI tokens include target and data as well as literal text.

No tokens for declarations.

No "textify" hash.

unget_token correctly handles partial tokens returned by get_tag().

begin_saving() and restore_saved()

EXAMPLES
Example:

use XML::TokeParser;
use strict;
#
my $text = '<tag foo="bar" foy="floy"> some text </tag>';
my $p = XML::TokeParser->new( \$text );
#
print $/;
#
while( defined( my $t = $p->get_token() ) ){
local $\="\n";
print ' raw = ', $t->raw;
#
if( $t->tag ){
print ' tag = ', $t->tag;
#
if( $t->is_start_tag ) {
print ' attr = ', join ',', %{$t->attr};
print ' attrseq = ', join ',', @{$t->attrseq};
}
#
print 'is_tag ', $t->is_tag;
print 'is_start_tag ', $t->is_start_tag;
print 'is_end_tag ', $t->is_end_tag;
}
elsif( $t->is_pi ){
print ' target = ', $t->target;
print ' data = ', $t->data;
print 'is_pi ', $t->is_pi;
}
else {
print ' text = ', $t->text;
print 'is_text ', $t->is_text;
print 'is_comment ', $t->is_comment;
}
#
print $/;
}
__END__

Output:

raw = <tag foo="bar" foy="floy">
tag = tag
attr = foo,bar,foy,floy
attrseq = foo,foy
is_tag 1
is_start_tag 1
is_end_tag 0

raw = some text
text = some text
is_text 1
is_comment 0

raw = 
text = comment
is_text 0
is_comment 1

raw = </tag>
tag = tag
is_tag 1
is_start_tag 0
is_end_tag 1

BUGS
To report bugs, go to
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=XML-TokeParser> or send mail
to <[email protected]>

AUTHOR
Copyright (c) 2003 D.H. aka PodMaster (current maintainer). Copyright
(c) 2001 Eric Bohlman (original author).

All rights reserved. This program is free software; you can redistribute
it and/or modify it under the same terms as Perl itself. If you don't
know what this means, visit <http://perl.com/> or <http://cpan.org/>.

SEE ALSO
HTML::TokeParser, XML::Parser, XML::Catalog, XML::Smart, XML::Twig.