#!/usr/bin/perl

use Text::Balanced qw{extract_multiple extract_bracketed extract_delim
+ited extract_tagged};

my $text = '<p>paragraph<b>BOLD text</p><a href=">>>>">link text</a><d
+iv><p>Some new text <b>in bold and <i>cursive</b></p></div><p>test</p
+>';

local $\ = $/;
print "text= $text";
my @stack;
my $error;

@fields = extract_multiple($text,
                   [
                        { Tag   => sub { extract_tagged($_[0]) } },
                        { Brack => sub { extract_bracketed($_[0],'<>')
+ } },
                   ],
                   undef,
                   0
                   );
foreach my $elem (@fields){
    if(ref( $elem ) eq 'Tag'){
        (print_stack(), $error--) if defined $error;
        print "OK Tag: ".$$elem;
    }
    elsif(ref $elem eq 'Brack'){
        my ($otag) = $$elem =~ m#<([a-zA-Z0-9]+)>#;
        my ($ctag) = $$elem =~ m#</([a-zA-Z0-9]+)>#;
        
        add_to_stack($otag)      if defined $otag;
        remove_from_stack($ctag) if defined $ctag;
    }
    else {
        $error = 1;
    }
}

sub print_stack {
    foreach my $tag (@stack){
        print "not properly closed: ". $tag if defined $tag;
    }
}

sub add_to_stack {
    push @stack, shift;
}

sub remove_from_stack {
    my $tag =  shift;
    foreach my $c (reverse 0 .. @stack) {
        delete $stack[$c]    if($stack[$c] eq $tag ) 
    }
}
[download]

text= <p>paragraph<b>BOLD text</p><a href=">>>>">link text</a><div><p>
+Some new text <b>in bold and <i>cursive</b></p></div><p>test</p>
not properly closed: b
OK Tag: <a href=">>>>">link text</a>
not properly closed: i
OK Tag: <p>test</p>
[download]