Sneak preview for NEScala

gistfile1.txt

scala> def foo[A, B, C](a: SNat[A], b: SNat[B], c: SNat[C])(implicit ssum: SSum[A, B, C]) = ssum
foo: [A, B, C](a: shapeless.SNat[A], b: shapeless.SNat[B], c: shapeless.SNat[C])(implicit ssum: shapeless.SSum[A,B,C])shapeless.SSum[A,B,C]

scala> foo(2, 3, 5)
res0: shapeless.SSum[Int(2),Int(3),Int(5)] = $anon$1@53d76e96

scala> foo(2, 3, 7)
<console>:15: error: could not find implicit value for parameter ssum: shapeless.SSum[Int(2),Int(3),Int(7)]
              foo(2, 3, 7)
                 ^

Fun :)
Why not add the following syntactic sugar?

type Args = { type Lhs; type Rhs }
type +[A, B] = Args { type Lhs = A; type Rhs = B }
type ==[A <: Args, B] = SSum[A#Lhs, A#Rhs, B]

def foo[A, B, C](a: SNat[A], b: SNat[B], c: SNat[C])(implicit ev: A + B == C) = ev

Man, you're beating that compiler bloody! Soon I'll ditch my old prolog code and just use scalac. I'll even leave the runtime at home.