#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use XML::LibXML;
use List::Util qw{ sum };

sub insert_tag {
    my ($text, $pos, $tag_name, $query) = @_;
    my $before = substr $text, 0, $pos;
    my $after  = substr $text, $pos;

    my $parent = $text->parentNode;
    $parent->insertBefore('XML::LibXML::Text'->new($before), $text);
    $parent->insertAfter('XML::LibXML::Text'->new($after), $text);
    my $tag = 'XML::LibXML::Element'->new($tag_name);
    $parent->replaceChild($tag, $text);
    $tag->{query} = $query;
}

my $xml = "<foo>The quick br<bar>o</bar>wn <baz>f<bar>o</bar>x</baz>";
$xml .= " jumps over the lazy d<bar>o</bar>g.</foo>";

my $new_element = "canid";
my @queried = ("lazy dog", "quick brown fox",);

my $dom = 'XML::LibXML'->load_xml(string => $xml);

for my $query (@queried) {
    my @texts = $dom->findnodes('//text()');
    my ($from, $to) = (0, 0);
    my $found;
  OUTER:
    while ($to <= $#texts) {
        my $subtext = join "", @texts[ $from .. $to ];
        for my $length (1 .. length $query) {
            my $subquery = substr $query, 0, $length;
            $found = index $subtext, $subquery;

            ++$to, next OUTER if -1 != $found
                              && $length < length $query
                              && $length == length($subtext) - $found;

            $to = ++$from, next OUTER if -1 == $found;
        }

        my $subtext_length = sum(map length, @texts[ $from .. $to ]);
        my $last_pos = length($texts[$to]) - ($subtext_length - $found - length $query);

        insert_tag($texts[$to], $last_pos, 'end', $query);
        insert_tag($texts[$from], $found, 'start', $query);

        last OUTER;
    }
}
print $dom;


##</code><code>##

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,