Someone

what i want is to enter stuff like this:
--------------------------
my $a = 1;
my $asdffdas = 2;
my $foo = 3;
--------------------------
hit the magic button and get
--------------------------
my $a        = 1;
my $asdffdas = 2;
my $foo      = 3;
--------------------------

In effect, i want to tell it to align every = to the one on the most right posistion. In a perfect world, i would be able to specify the regexp of what should be aligned.