whatpm/What/HTML.pod

=head1 NAME

What::HTML - An HTML Parser

=head1 SYNOPSIS

  use What::HTML;
  
  my $s = q<<!DOCTYPE html><html>...</html>>;
  # $doc = an empty DOM |Document| object
  my $on_error = sub {
    my $error_code = shift;
    warn $error_code, "\n";
  };
  
  What::HTML->parse_string ($s => $doc, $onerror);
  
  ## Then, |$doc| is the DOM representation of |$s|.

=head1 DESCRIPTION

The C<What::HTML> module contains HTML parser and serializer.

The HTML parser can be used to construct the DOM tree representation
from an HTML document.  The parsing and tree construction are done 
as described in the Web Application 1.0 specification.

The HTML serializer can be used to obtain the HTML document representation
of a DOM tree (or a tree fragment thereof).  The serialization
is performed as described in the Web Applications 1.0 specification
for C<innerHTML> DOM attribute.

This module is part of WHAT.pm - Perl Modules for 
Web Hypertext Application Technologies.

=head1 METHODS

=over 4

=item [I<$doc> =] What::HTML->parse_string (I<$s>, I<$doc>[, I<$onerror>]);

Parse a string I<$s> as an HTML document.

The first argument, I<$s>, MUST be a string.  It is parsed
as a sequence of characters representing an HTML document.

The second argument, I<$doc>, MUST be an empty read-write 
DOM C<Document> object.  The HTML DOM tree is constructed
onto this C<Document> object.

The third argument, I<$onerror>, MUST be a reference to
the error handler code.  Whenever a parse error is detected,
this code is invoked with an argument that contains a
useless string that might describe what is wrong.
The code MAY throw an exception, so that whole the parsing
process aborts.  Otherwise, the parser will continue to
process the input.  The code MUST NOT modify I<$s> or I<$doc>.
If it does, then the result is undefined.
This argument is optional; if missing, any
parse error makes that string being C<warn>ed.

The method returns the DOM C<Document> object (i.e. the second argument).

Note that the C<What::NanoDOM> module provides a non-conforming
implementation of DOM that only implements the subset that
is necessary for the purpose of C<What::HTML>'s parsing and
serializing.
With this module, creating a new HTML C<Document> object
from a string containing HTML document can be coded as:

  use What::HTML;
  use What::NanoDOM;
  my $doc = What::HTML->parse_string ($s => What::NanoDOM->new, $onerror);

=item I<$s> = What::HTML->get_inner_html (I<$node>[, I<$onerror>]);

Return the HTML serialization of a DOM node I<$node>.

The first argument, I<$node>, MUST be a DOM C<Document>,
C<Node>, or C<DocumentFragment> object.

The second argument, I<$onerror>, MUST be a reference to the
error handling code.  This code will be invoked if a descendant
of C<$node> is not of C<Element>, C<Text>, C<CDATASection>,
C<Comment>, C<DocumentType>, or C<EntityReference> so
that C<INVALID_STATE_ERR> MUST be thrown.
The code will be invoked with an argument, which is the node
whose type is invalid.  
This argument is optional; if missing, any such
node is simply ignored.

The method returns the C<inner_html> attribute
value, i.e. the HTML serialization of the C<$node>.

=back

=head1 TO DO

Tokenizer should emit a sequence of character tokens as one token
to improve performance.

A method that accepts a byte stream as an input.

Charset detection algorithm.

Setting inner_html.

And there are many "TODO"s and "ISSUE"s in the source code.

=head1 SEE ALSO

Web Applications 1.0 Working Draft (aka HTML5)
<http://whatwg.org/html5>.  (Revision 792, 1 May 2007)

L<What::NanoDOM>

=head1 AUTHOR

Wakaba <w@suika.fam.cx>.

=head1 LICENSE

Copyright 2007 Wakaba <w@suika.fam.cx>

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

=cut

# $Date: 2007/05/01 08:17:44 $
1	=head1 NAME
2
3	What::HTML - An HTML Parser
4
5	=head1 SYNOPSIS
6
7	use What::HTML;
8
9	my $s = q<<!DOCTYPE html><html>...</html>>;
10	# $doc = an empty DOM \|Document\| object
11	my $on_error = sub {
12	my $error_code = shift;
13	warn $error_code, "\n";
14	};
15
16	What::HTML->parse_string ($s => $doc, $onerror);
17
18	## Then, \|$doc\| is the DOM representation of \|$s\|.
19
20	=head1 DESCRIPTION
21
22	The C<What::HTML> module contains HTML parser and serializer.
23
24	The HTML parser can be used to construct the DOM tree representation
25	from an HTML document. The parsing and tree construction are done
26	as described in the Web Application 1.0 specification.
27
28	The HTML serializer can be used to obtain the HTML document representation
29	of a DOM tree (or a tree fragment thereof). The serialization
30	is performed as described in the Web Applications 1.0 specification
31	for C<innerHTML> DOM attribute.
32
33	This module is part of WHAT.pm - Perl Modules for
34	Web Hypertext Application Technologies.
35
36	=head1 METHODS
37
38	=over 4
39
40	=item [I<$doc> =] What::HTML->parse_string (I<$s>, I<$doc>[, I<$onerror>]);
41
42	Parse a string I<$s> as an HTML document.
43
44	The first argument, I<$s>, MUST be a string. It is parsed
45	as a sequence of characters representing an HTML document.
46
47	The second argument, I<$doc>, MUST be an empty read-write
48	DOM C<Document> object. The HTML DOM tree is constructed
49	onto this C<Document> object.
50
51	The third argument, I<$onerror>, MUST be a reference to
52	the error handler code. Whenever a parse error is detected,
53	this code is invoked with an argument that contains a
54	useless string that might describe what is wrong.
55	The code MAY throw an exception, so that whole the parsing
56	process aborts. Otherwise, the parser will continue to
57	process the input. The code MUST NOT modify I<$s> or I<$doc>.
58	If it does, then the result is undefined.
59	This argument is optional; if missing, any
60	parse error makes that string being C<warn>ed.
61
62	The method returns the DOM C<Document> object (i.e. the second argument).
63
64	Note that the C<What::NanoDOM> module provides a non-conforming
65	implementation of DOM that only implements the subset that
66	is necessary for the purpose of C<What::HTML>'s parsing and
67	serializing.
68	With this module, creating a new HTML C<Document> object
69	from a string containing HTML document can be coded as:
70
71	use What::HTML;
72	use What::NanoDOM;
73	my $doc = What::HTML->parse_string ($s => What::NanoDOM->new, $onerror);
74
75	=item I<$s> = What::HTML->get_inner_html (I<$node>[, I<$onerror>]);
76
77	Return the HTML serialization of a DOM node I<$node>.
78
79	The first argument, I<$node>, MUST be a DOM C<Document>,
80	C<Node>, or C<DocumentFragment> object.
81
82	The second argument, I<$onerror>, MUST be a reference to the
83	error handling code. This code will be invoked if a descendant
84	of C<$node> is not of C<Element>, C<Text>, C<CDATASection>,
85	C<Comment>, C<DocumentType>, or C<EntityReference> so
86	that C<INVALID_STATE_ERR> MUST be thrown.
87	The code will be invoked with an argument, which is the node
88	whose type is invalid.
89	This argument is optional; if missing, any such
90	node is simply ignored.
91
92	The method returns the C<inner_html> attribute
93	value, i.e. the HTML serialization of the C<$node>.
94
95	=back
96
97	=head1 TO DO
98
99	Tokenizer should emit a sequence of character tokens as one token
100	to improve performance.
101
102	A method that accepts a byte stream as an input.
103
104	Charset detection algorithm.
105
106	Setting inner_html.
107
108	And there are many "TODO"s and "ISSUE"s in the source code.
109
110	=head1 SEE ALSO
111
112	Web Applications 1.0 Working Draft (aka HTML5)
113	<http://whatwg.org/html5>. (Revision 792, 1 May 2007)
114
115	L<What::NanoDOM>
116
117	=head1 AUTHOR
118
119	Wakaba <w@suika.fam.cx>.
120
121	=head1 LICENSE
122
123	Copyright 2007 Wakaba <w@suika.fam.cx>
124
125	This library is free software; you can redistribute it
126	and/or modify it under the same terms as Perl itself.
127
128	=cut
129
130	# $Date: 2007/05/01 08:17:44 $