currying functions (idea)

sub foo
{
        my $x = shift;

        sub {
                my $y = shift;

                sub { my $z = shift; $x * $y + $z }
        }
}

print foo(2)->(3)->(4), "\n";

When foo is called with the argument 2, it returns a function equivalent to

sub foo_1 { my $y = shift; sub { my $z = shift; 2 * $y + $z } }

When this function is called with the argument 3, it returns a function equivalent to

sub foo_2 { my $z = shift; 2 * 3 + $z }

And when this function is called, with the argument 4, it obviously returns the value 10.

You can also do emulation of currying another way, by doing things such as

sub plus_2 { $_[0] + 2 }

such that you have the same effect that you might achieve by writing

plus_2 = (+) 2

or somesuch in Haskell.

Of course, these examples aren't very useful in themselves, but the ideas are conceivably useful.