#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
use Math::Fibonacci qw( isfibonacci );

my $string = '377';

sub mySubString {
    my ($string, $offset, $length) = @_;
    return substr $string, $offset, $length;
}

sub fibonacciCompare {
    my ($s, $iteration) = @_;
    my @matched;
    for (1..length($s)) {
	my $inToCompare = mySubString($s, $iteration, $_);
	my $fibonacci = isfibonacci($inToCompare);
	push @matched, "Matched: $inToCompare" if ($fibonacci);
    }
    return \@matched if $matched[0];
}

my $final = fibonacciCompare($string, 0);
print Dumper $final if $final;

__END__

$ perl test.pl
$VAR1 = [
          'Matched: 3',
          'Matched: 377'
        ];