NAME

Whatpm::ContentChecker - DOM Conformance Checker

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";
  });

DESCRIPTION

The 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.

METHODS

This module contains two static methods:

Whatpm::ContentChecker->check_document ($document, $onerror);: Checks a document, $document, and its descendant for their conformance. If there is an error or a warnign, then the $onerror CODE is invoked with named arguments same as ones for the method check_element.
Whatpm::ContentChecker->check_element ($element, $onerror);: Checks an element, $element, and its descendant for their conformance. If there is an error or a warning, then the $onerror CODE is invoked with named arguments:

BUGS

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

NOTES ON IMPLEMENTATION DETAILS

This section is not complete.

This section describes various internal constructions used in the Whatpm::ContentChecker manpage and relevant modules. These data structures are not public interfaces -- they should not be accessed or modified by applications. They are documented here for the convenience of development only.

The `$self->{flag}` Structure

$self->{flag}->{has_label}: This flag is set to a true value if and only if there is a label element ancestor of the current node.
$self->{flag}->{has_labelable}: This flag is set to 1 if and only if a nearest ancestor label element has the for attribute and there is no labelable form-associated element that is a descendant of the label element and precedes the current node in tree order. This flag is set to 2 if and only if there is a labelable form-associated element that is a descendant of the nearest ancestor label element of the current node and precedes the current node in tree order. This flag is otherwise set to a false value. However, when there is no ancestor label element of the current node, i.e. when $self->{flag}->{has_label} is false, the value of the $self->{flag}->{has_labelable} flag is undefined.

The `$element_state` Structure

$element_state->{has_label_original}: Used to preserve the value of $self->{flag}->{has_label} at the time of invocation of the method element_start for the element being checked.
$element_state->{has_labelable_original}: Used to preserve the value of $self->{flag}->{has_labelable} at the time of invocation of the method element_start for the element being checked.

AUTHOR

Wakaba <w@suika.fam.cx>

LICENSE

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