Perl function knowing receiver type

Question

I have a text file, and a function to retrieve from that text file:

@thefile = read_file( 'somepathfile' );

I would like to have a different implementation of the read_file function depending on which type is receiving the information.

So if I write:

%thefile = read_file( 'somepathfile' );

then a different function will be executed.

How do I do that?

Answer 1

Have a look at Want or Contextual::Return CPAN modules.

Below is a simple example using Want:

use strict;
use warnings;
use Want;

sub read_file {
    my $filepath = shift;
    my @file_contents = get_file_contents($filepath);

    return @file_contents if want('LIST');

    return { 
        filepath => $filepath, 
        content  => \@file_contents, 
        lines    => scalar @file_contents 
    } if want('HASH');

    die "Nothing for that context!";
}

my @list = read_file('foo');
my %hash = %{ read_file('foo') };

NB. The hash dereference is needed to force the return context.

/I3az/

Answer 2

While draegtun's answer illustrates a nice technique, I am going to recommend clarity. For example:

@thefile = read_file_lines( 'somepathfile' );

%thefile = read_file_pairs( 'somepathfile' );