Is this snippet creating an anonymous Perl hash?

Question

While reading the snippets provided by FormFiller ( where I kinda got by accident ) , I noticed this line:

$f->add_filler( password => Interactive => []);

Is this password => Interactive => [] equivalent to {"password" => {"Interactive"=>[]}}? If not, what does it become?

Answer 1

=> is semantically (almost) identical to , (see "Comma operator" at perldoc perlop), so you're doing this:

$f->add_filler( 'password', 'Interactive', [] );

If this calling style is supported by the method (which it doesn't), then it itself would have to convert these arguments into

{ password => { Interactive => [] } }

However more typically, hash-style arguments would be passed as a legal hash to begin with:

$f->add_filler( password => { Interactive => 1 } );

This would be received by the function like this:

sub add_filler
{
    my $this = shift;
    my %configs = @_;
    # ...
}

Answer 2

No, it's exactly the same as

$f->add_filler( "password", "Interactive", []);

Answer 3

The Data::Dumper module is great for answering questions like this. Use the following mock:

package Foo;
use Data::Dumper;
sub new { bless {} => shift }
sub add_filler {
  my $self = shift;
  print Dumper \@_;
}

Then call it

package main;
my $f = Foo->new;
$f->add_filler( password => Interactive => []);

and see when you get:

$VAR1 = [
          'password',
          'Interactive',
          []
        ];

This shows that add_filler receives a flat list of three arguments: two strings and a reference to an anonymous array.