$ perl -e 'my $x = " X "; $x =~ s/^\s+|\s+$//; print "|$x|";'
|X |

$ perl -e 'my $x = " X "; $x =~ s/^\s+|\s+$//g; print "|$x|";'
|X|

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;

sub GET_DATA ();

my @user_tests = (
    {
        ref_lang => { match => 1, strings => ['hollow log', 'fence'], },
        'Lang A' => { match => 1, strings => ['jumped'], },
        'Lang Q' => { match => 0, strings => ['red fox'], },
    },
    {
        ref_lang => { match => 1, strings => ['tree', 'fence'], },
        'Lang A' => { match => 1, strings => ['tree', 'doe'], },
        'Lang Q' => { match => 0, strings => ['gray fox'], },
    },
);

for my $i (0 .. $#user_tests) {
    processComparison(GET_DATA, $user_tests[$i], $i);
}

sub processComparison {
    my ($data, $test, $index) = @_;

    my %results;

    for my $lang (keys %$test) {
        $results{$lang} = check_match($data->{$lang}, $test->{$lang});
    }

    # For demo
    use Data::Dump;
    print "User Test Index $index:\n";
    dd $test;
    print "Results:\n";
    dd \%results;
    print '-' x 60, "\n";

    return;
}

sub check_match {
    my ($data, $test) = @_;

    my @results;

    DATUM: for my $i (0 .. $#$data) {
        STRING: for my $string (@{$test->{strings}}) {
            next STRING unless match_ok(
                $test->{match}, index $data->[$i], $string
            );
            push @results, $i + 1;
            next DATUM;
        }
    }

    return \@results;
}

sub match_ok {
    my ($match, $index) = @_;

    return $match ? $index > -1 : $index == -1;
}

sub GET_DATA () {
    return {
        ref_lang => [
            'The red fox jumped over the hollow log.',
            'The tall tree towered over the animals.',
            'The tawny deer jumped over the fence.',
        ],
        'Lang A' => [
            'The vixen jumped over the brown log.',
            'The tree swayed smartly in the field.',
            'The doe jumped over the barrier.',
        ],
        'Lang Q' => [
            'The gray fox jumped over the big log.',
            'The tall tree grew in the field.',
            'The red deer cleared the tall fence.',
        ],
    };
}

##</code><code>##

User Test Index 0:
{
  "Lang A"   => { match => 1, strings => ["jumped"] },
  "Lang Q"   => { match => 0, strings => ["red fox"] },
  "ref_lang" => { match => 1, strings => ["hollow log", "fence"] },
}
Results:
{ "Lang A" => [1, 3], "Lang Q" => [1, 2, 3], "ref_lang" => [1, 3] }
------------------------------------------------------------
User Test Index 1:
{
  "Lang A"   => { match => 1, strings => ["tree", "doe"] },
  "Lang Q"   => { match => 0, strings => ["gray fox"] },
  "ref_lang" => { match => 1, strings => ["tree", "fence"] },
}
Results:
{ "Lang A" => [2, 3], "Lang Q" => [2, 3], "ref_lang" => [2, 3] }
------------------------------------------------------------