=head1 NAME

Whatpm::ContentChecker - DOM Conformance Checker

=head1 SYNOPSIS

  use Whatpm::ContentChecker;
  
  Whatpm::ContentChecker->check_document ($doc, sub {
    my %arg = @_;
    warn get_node_path ($arg{node}), ": ",
        ($arg{level} || "Error"), ": ",
        $arg{type}, "\n";
  });
  
  Whatpm::ContentChecker->check_element ($doc, sub {
    my %arg = @_;
    warn get_node_path ($arg{node}), ": ",
        ($arg{level} || "Error"), ": ",
        $arg{type}, "\n";
  });

=head1 DESCRIPTION

The C<Whatpm::ContentChecker> Perl module contains two methods
to validate DOM tree for its conformance to the markup language
in use.

This module is part of Whatpm, Perl Modules for
Web Hypertext Application Technologies, which is a subproject
of manakai.

=head1 METHODS

This module contains two static methods:

=over 4

=item Whatpm::ContentChecker->check_document (I<$document>, I<$onerror>);

Checks a document, I<$document>, and its descendant for their
conformance.  If there is an error or a warnign, then the
I<$onerror> C<CODE> is invoked with named arguments same
as ones for the method C<check_element>.

=item Whatpm::ContentChecker->check_element (I<$element>, I<$onerror>);

Checks an element, I<$element>, and its descendant for their conformance.
If there is an error or a warning, then the I<$onerror> C<CODE>
is invoked with named arguments:

=over 4

=item level (Might be C<undef>)

A string which describes the severity of the error or warning.
For the list of the severities, see
<http://suika.fam.cx/gate/2005/sw/Whatpm%20Error%20Types>.

=item node (Always specified)

The node with which the error is detected.

=item type (Always specified)

A string which describes the type of the error or warning.
For the list of the errors and warnings, see
<http://suika.fam.cx/gate/2005/sw/Whatpm%20Error%20Types>.

=back

=back

=head1 BUGS

This conformance checker is work in progress; it I<might> not be
able to detect all the errors in the DOM tree, and it I<might> 
detect an error for a node that is conforming in fact.

=head1 SEE ALSO

L<Whatpm::ContentChecker::Atom>

L<Whatpm::ContentChecker::HTML>

<http://suika.fam.cx/gate/2005/sw/Whatpm%20Error%20Types>

=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: 2007/08/06 10:56:50 $