use 5.010;
use strict;
use warnings;

my %types = (
    square => {dimensions => ['side'], calc => \&calcSquare},
    rectangle     => {dimensions => ['width', 'height'], calc => \&calcRect},
    parallelogram => {dimensions => ['base',  'height'], calc => \&calcRect},
);

say "I am an area calculator.";

while (1) {
    say "Enter stop to stop or one of: ", join ' ', sort keys %types;
    print "What type of shape am I working with? ";

    my $type = <>;
    chomp ($type);

    last if lc $type eq 'stop';

    if (!exists $types{lc $type}) {
        say "Sorry, I don't know about $type.";
        next;
    }

    my @dims;

    for my $dim (@{$types{$type}{dimensions}}) {
        print "Enter a value for $dim:";

        my $value = <>;
        chomp $value;
        push @dims, $value;
    }

    say "The area or your $type is: ", $types{$type}{calc}->(@dims);
}

say "Thanks for using me. Come again sometime";


sub calcSquare {
    return $_[0] * $_[0];
}


sub calcRect {
    return $_[0] * $_[1];
}