Question

use 5.010;
use strict;
use warnings;
use JSON::XS;
use YAML::XS;
my %data = ();
my $content = <<HERE;
{
  "name":"BLAHBLAH","contact":{"phone":"12345","twitter":"BLAHBLAH"},
  "location": {"address":"NOTTELLING","lat":10,"lng":10,"postalCode":"1234",
  "city":"BLAH","state":"BLAH","country":"BLAH"},
  "categories":[{"id":"BLAH","name":"BLAH"}]
}
HERE

my $id = "name1";

sub function {
    my ( $id, $data, $content ) = @_;
    my %data = %$data;
    my $out = decode_json($content);
    say "out:", Dump $out;
    $data{$id} = $out;
}

function( $id, \%data, $content );
say "data:", Dump %data;

This doesn’t work as the way I expected. Can you please tell me why and how it will work?

Answer 1

The reason that you’re not finding anything in the package-scoped %data (the one defined just after use YAML::XS) is because you’re creating a brand-new and completely independent %data inside of function with the line

my %data = %$data;

This creates a new hash and copies the contents of the hash referenced by $data into it.

Try this instead:

sub function {
  my ($id, $data, $content) = @_;
  my $out = decode_json($content);
  say "out:", Dump $out;
  $data->{$id} = $out;
}