#!/usr/bin/perl

use strict;
use warnings;

sub multiply($$) { (pop)*(pop) } 

print multiply 4, 5;
print "\n";

sub to ($) { (shift) }      # just syntactic sugar
sub on ($) { (shift) }      # also syntactic sugar

sub add {                   # currying
    my $op = shift;
    return sub { (shift) + $op }
}

print add(5)->(on add(3)->(to 4));