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 <!--comment--></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 = <!--comment-->
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 <bug-XML-Tokeparser@rt.cpan.org>
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.