At first I thought about Test::More's is_deeply, which compares two nested data structures for testing purposes. But it seems like Data::Compare does the same job pretty well for common programs. You can either use one of the two, or look at the source code to understand how they work.

Besides Data::Compare proposed by Eily, there are also Data::Walk and Data::Walker. When you put it together the problem seems to have a reasonably simple and neat solution:

use strict;
use warnings;

use Data::Walk;
use Data::Compare;

sub find_structure_part {
    my $search_space = shift;
    my $target = shift;
    my $found = 0;

    walk sub {
        if (not $found and Compare($_, $target)) { $found = 1 }
    }, $search_space;

    return $found;
}
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I'm with Eily. Data::Compare does this work very well. Here's an example:

use warnings;
use strict;

use Data::Compare;

my $part = {
          'c' => {},
          'func' => []
        };


my $main = {
    'a' => {
        'b' => {
            'c' => {},
            'func' => []
        },
        'func' => [
            'd',
            'e'
        ]
    }
};

for my $inner (keys %$main){
    for my $key (keys %{ $main->{$inner} }){
        my $its_here = Compare $part, $main->{$inner}{$key};
        if ($its_here){
            print "found at location $key\n";
        }
    }
}
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Hello k_manimuthu,

Combining your recursive approach with the Test::Deep::eq_deeply function suggested by Eily’s post, I came up with the following:

#! perl
use strict;
use warnings;
use Test::Deep::NoTest;

my $x =
{
    c    => {},
    func => [],
};

my $x1 =
{
    func => [],
    c    => {},
};

my $x2 =
{
    func => [],
    c    => { s => 't' },
};

my $main =
{
    a =>
    {
        b    =>
        {
            c    => {},     ### equals to $part hash reference
            func => [],
        },
        func =>
        [
            'd',
            'e',
        ],
    },
};

printf "%s found\n", walk($main, $x ) ? 'Match' : 'No match';
printf "%s found\n", walk($x,    $x1) ? 'Match' : 'No match';
printf "%s found\n", walk($main, $x2) ? 'Match' : 'No match';

sub walk
{
    my ($whole, $part) = @_;
    my  $ref = ref $whole;

    return 1 if eq_deeply($whole, $part);

    if    ($ref eq 'ARRAY')
    {
        for (@$whole)
        {
            if (eq_deeply($_, $part))
            {
                return 1;
            }
            else
            {
                return 1 if walk($_, $part);
            }
        }
    }
    elsif ($ref eq 'HASH')
    {
        for (keys %$whole)
        {
            if (eq_deeply($whole->{$_}, $part))
            {
                return 1;
            }
            else
            {
                return 1 if walk($whole->{$_}, $part);
            }
        }
    }

    return 0;
}
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Output:

 0:08 >perl 1414_SoPW.pl
Match found
Match found
No match found

 0:08 >
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The results shown are as expected; however... (disclaimer) a lot more, and more rigorous, testing is still required!

Anyway, hope that helps,

Thanks a lot for all your suggestions...

Comparing the value of one ref to another would only work if they were created to point to the same variable. Perl doesn't compare the contents of references automatically, and a simple eq won't work for anything other than a scalar.

DB<1> $ans1=42
DB<2> $ref1=\$ans1
DB<3> $ref2=\$ans1
DB<4> if ($ref1 eq $ref2) { print "match\n" }
match
DB<5> $ans2 = 42
DB<6> $ref2 = \$ans2
DB<7> if ($ref1 eq $ref2) { print "match\n" }
DB<8> if ($$ref1 eq $$ref2)  { print "match\n" }
match
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