That's exactly the case where Data::Diver is helpful! 
#!/usr/bin/perl
use warnings;
use strict;

use Data::Diver qw{ Dive };

my $external_structure = { ... };

my %format = (product_id     => ['id'],
              price_excl_vat => [qw[ data price ]],
              unit_qty       => [qw[ data unit_info qty ]]);  # (1)

my $internal_structure = {};
for my $key (keys %format) {
    $internal_structure->{$key}
        = Dive($external_structure, @{ $format{$key} });
}

use Data::Dumper; print Dumper $internal_structure;

[download]

(1) Note that the second element of the path is unit_info, not just unit.

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re: Mapping data structures through external source by choroba
in thread Mapping data structures through external source by DreamT

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