In this version I pass around a closure code reference to get evaluated when we find matching fields.

I find this much prettier, since we aren't duplicating the ref code and it simplifies the matching code.

#!/usr/bin/perl -w

use strict;
use Data::Dumper;
use Test::More tests => 1;

my $element = {
          'check' => {
                     'field' => 'OLK_BO_BK_TYPE'
                   },
          'type' => 'case',
          'case' => [
                    {
                      'value' => '1',
                      'resultset' => 'BROKER'
                    },
                    {
                      'value' => '3',
                      'resultset' => {
                                      'field' => 'OLK_BO_BK_DESC'
                                     },
                    },
                  ]
        };

my $expected = {
          'check' => 'OLK_BO_BK_TYPE',
          'type' => 'case',
          'case' => [
                    {
                      'value' => '1',
                      'resultset' => 'BROKER'
                    },
                    {
                      'value' => '3',
                      'resultset' => 'OLK_BO_BK_DESC',
                    },
                  ]
        };

hash_walk($element);
is_deeply( $element, $expected, "hash_walk worked as expected");

sub hash_walk {
    my ( $element, $update ) = @_;

    if ( ref($element) =~ /HASH/ ) {
        foreach my $key ( keys %$element ) {
        my $value = $element->{$key};
            if ( $key =~ /field/ ) {
        $update->( $value);
            }
            else {
                hash_walk( $value,
                    sub { $element->{$key} = shift } );
            }
        }
    }
    elsif ( ref($element) =~ /ARRAY/ ) {
        my $upper = @$element - 1;
        foreach my $i ( 0 .. $upper ) {
            my $index = $element->[$i];
            hash_walk( $index, sub { $element->[$i] = shift } );
        }
    }
}
[download]