Greetings,

I'm trying to use named parameters with default values. For a normal hash this is simple, but I have a more complex data structure.

#!/usr/bin/perl

use strict;
use warnings;
use feature 'say';
use Data::Dumper;

my %valid_inputs = (
   one => 1,
   two => 2
);

validate(
   valid_inputs => \%valid_inputs,
   max_record_length => 72,
);

sub validate
{
   my %params = (
      valid_inputs => {
         one   => 'one',
         two   => 'two',
         three => 'three',
         four  => 'four',
      },
      max_record_length => 24,
      @_,
   );
  
   my $valid_inputs = $params{valid_inputs};
   say '@_ ['.Dumper( \@_ ).']';
   say '%params ['.Dumper( \%params ).']';
   say '%valid_inputs ['.Dumper( \%valid_inputs ).']';

}
#EOF

Output:
@_ [$VAR1 = [
          'valid_inputs',
          {
            'two' => 2,
            'one' => 1
          },
          'max_record_length',
          72
        ];
]
%params [$VAR1 = {
          'valid_inputs' => {
                              'two' => 2,
                              'one' => 1
                            },
          'max_record_length' => 72
        };
]
%valid_inputs [$VAR1 = {
          'two' => 2,
          'one' => 1
        };
]
[download]

Because valid_inputs is a reference it over writes the defaults completely rather than just the same keys as with max_record_length. If make valid_inputs not a refence the final complete hash is scrambled and flat. Is there an elegant solution?

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