package HTML::Tagset;

use strict;

=head1 NAME

HTML::Tagset - data tables useful in parsing HTML

=head1 VERSION

Version 3.20

=cut

use vars qw( $VERSION );

$VERSION = '3.20';

=head1 SYNOPSIS

  use HTML::Tagset;
  # Then use any of the items in the HTML::Tagset package
  #  as need arises

=head1 DESCRIPTION

This module contains several data tables useful in various kinds of
HTML parsing operations.

Note that all tag names used are lowercase.

In the following documentation, a "hashset" is a hash being used as a
set -- the hash conveys that its keys are there, and the actual values
associated with the keys are not significant.  (But what values are
there, are always true.)

=cut

use vars qw(
    $VERSION
    %emptyElement %optionalEndTag %linkElements %boolean_attr
    %isHeadElement %isBodyElement %isPhraseMarkup
    %is_Possible_Strict_P_Content
    %isHeadOrBodyElement
    %isList %isTableElement %isFormElement
    %isKnown %canTighten
    @p_closure_barriers
    %isCDATA_Parent
);

=head1 VARIABLES

Note that none of these variables are exported.

=head2 hashset %HTML::Tagset::emptyElement

This hashset has as values the tag-names (GIs) of elements that cannot
have content.  (For example, "base", "br", "hr".)  So
C<$HTML::Tagset::emptyElement{'hr'}> exists and is true.
C<$HTML::Tagset::emptyElement{'dl'}> does not exist, and so is not true.

=cut

%emptyElement   = map {; $_ => 1 } qw(base link meta isindex
                                     img br hr wbr
                                     input area param
                                     embed bgsound spacer
                                     basefont col frame
                                     ~comment ~literal
                                     ~declaration ~pi
                                    );
# The "~"-initial names are for pseudo-elements used by HTML::Entities
#  and TreeBuilder

=head2 hashset %HTML::Tagset::optionalEndTag

This hashset lists tag-names for elements that can have content, but whose
end-tags are generally, "safely", omissible.  Example:
C<$HTML::Tagset::emptyElement{'li'}> exists and is true.

=cut

%optionalEndTag = map {; $_ => 1 } qw(p li dt dd); # option th tr td);

=head2 hash %HTML::Tagset::linkElements

Values in this hash are tagnames for elements that might contain
links, and the value for each is a reference to an array of the names
of attributes whose values can be links.

=cut

%linkElements =
(
 'a'       => ['href'],
 'applet'  => ['archive', 'codebase', 'code'],
 'area'    => ['href'],
 'base'    => ['href'],
 'bgsound' => ['src'],
 'blockquote' => ['cite'],