examples/Markus/identity(2).spl

   1 // Various versions of the identity function
   2
   3 // Identity for integers
   4 // The type signature forces the function to have a more concrete type than it could have.
   5 id_int(x) :: Int -> Int
   6 {
   7   return x;
   8 }
   9
  10
  11 // Polymorphic identity with type signature
  12 id_poly_with(x) :: a -> a
  13 {
  14   return x;
  15 }//
  16
  17
  18 //// Polymorphic identity without type signature
  19 //// Type checking should figure out the type forall a . a -> a
  20 //id_poly_without(x)
  21 //{
  22 //  return x;
  23 //}//
  24
  25
  26 // Clumsy polymorphic identity
  27 // Type checking should give type forall a . a -> a
  28 id_poly_wtf(x) :: a -> a
  29 {
  30   var a = x;
  31   var b = a;
  32   var c = b;
  33   return c;
  34 }//
  35
  36
  37 //// Clumsy identity for integers
  38 //// Type checking should give type Int -> Int
  39 //id_int_wtf(x)
  40 //{
  41 //  var a = x;
  42 //  Int b = a;
  43 //  var c = b;
  44 //  return c;
  45 //}