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|
datatype pair a b = Pair of a * b
structure M : sig
class default
val get : t ::: Type -> default t -> t
val string_default : default string
val int_default : default int
val option_default : t ::: Type -> default t -> default (option t)
val pair_default : a ::: Type -> b ::: Type -> default a -> default b -> default (pair a b)
(*val uh_oh : t ::: Type -> default t -> default t*)
class awesome
val awesome_default : t ::: Type -> awesome t -> default t
val float_awesome : awesome float
val oh_my : t ::: Type -> awesome (option t) -> awesome (option t)
val awesome : t ::: Type -> awesome t -> t
end = struct
class default t = t
fun get (t ::: Type) (x : t) = x
val string_default = "Hi"
val int_default = 0
fun option_default (t ::: Type) (x : t) = Some x
fun pair_default (a ::: Type) (b ::: Type) (x : a) (y : b) = Pair (x, y)
(*fun uh_oh (t ::: Type) (x : t) = x*)
class awesome t = t
fun awesome_default (t ::: Type) (x : t) = x
val float_awesome = 1.23
fun oh_my (t ::: Type) (x : option t) = x
fun awesome (t ::: Type) (x : t) = x
end
open M
fun default (t ::: Type) (_ : default t) : t = get
val hi : string = default
val zero : int = default
val some_zero : option int = default
val hi_zero : pair string int = default
val ott : float = default
fun frob (t ::: Type) (_ : default t) : t = default
val hi_again : string = frob
val zero_again : int = frob
fun show_option (t ::: Type) (_ : show t) : show (option t) =
mkShow (fn x =>
case x of
None => "None"
| Some y => show y)
(*val x : option float = awesome*)
fun show_pair (a ::: Type) (b ::: Type) (_ : show a) (_ : show b) : show (pair a b) =
mkShow (fn x =>
case x of
Pair (y, z) => "(" ^ show y ^ "," ^ show z ^ ")")
fun main () : transaction page = return <xml><body>
{[hi_again]}, {[zero_again]}, {[some_zero]}, {[hi_zero]}, {[ott]}
</body></xml>
|
