design of lambda type signatures

Hey /praha/, what do you guys look for in a lambda type signature?

I personally like to see their smile. No, i mean, homoiconicity and uniform definition and declaration.

Anyways, which would you rather use everyday?


function<int, int -> int> foo;

foo = [int a, int b -> int] {
  return a + b;
}

or perhaps


function<int | int, int> foo;

foo = [int | int, int] {
  return a + b;
}

or anything else? Comparisons to other languages would be appreciated.

Go-style: foo = [int a, int b] int { return a + b; }
Actionscript-style: foo = [a:int, b:int]:int { return a + b; }