Glossary

my ($dl) = $tree->look_down('_tag', 'dl'); ##

##

my $dl = $tree->look_down('_tag', 'dl');

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##

#!/usr/bin/perl -W
use strict;
use HTML::TreeBuilder;

my $tree = HTML::TreeBuilder->new_from_content(<<'END') or die;

 
 Glossary
 Glossary

E Definition
E - data

B Definition
B - data

A_definition
A data.

C definition
C - data


 
 
END

my $dl = $tree->look_down( _tag => 'dl' );

# Unlink all of $dl's children from $dl, and return them.
my @dl_content = $dl->detach_content();

# Group the tags into an AoA on the DT tag.
my @dt_tag_clusters;
foreach (@dl_content) {
  push @dt_tag_clusters, [] if $_->tag() eq 'dt';
  die "Tags occured before first DT" unless @dt_tag_clusters;
  push @{ $dt_tag_clusters[-1] }, $_;
}

# Sort the clusters
@dt_tag_clusters = map  { $_->[1] }
                   sort { $a->[0] cmp $b->[0] }
                   map  { [ $_->[0]->as_HTML, $_ ] }
                   @dt_tag_clusters;

# Un-cluster the tags.
@dl_content = map { @$_ } @dt_tag_clusters;

# Replace the DL's content with the sorted tags.
$dl->push_content( @dl_content );

print $tree->as_HTML; # or use HTML::PrettyPrinter

$tree = $tree->delete();