Ur/Web: tests/type_class.lac annotate

Signature ascription for type classes

author	Adam Chlipala <adamc@hcoop.net>
date	Sat, 16 Aug 2008 16:57:21 -0400
parents	ba4d7c33a45f
children

rev	line source
adamc@211	1 class default t = t
adamc@211	2
adamc@212	3 val string_default : default string = "Hi"
adamc@211	4 val int_default : default int = 0
adamc@211	5
adamc@211	6 val default : t :: Type -> default t -> t =
adamc@211	7 fn t :: Type => fn d : default t => d
adamc@212	8 val hi = default [string] _
adamc@211	9 val zero = default [int] _
adamc@212	10
adamc@212	11 val frob : t :: Type -> default t -> t =
adamc@212	12 fn t :: Type => fn _ : default t => default [t] _
adamc@212	13 val hi_again = frob [string] _
adamc@212	14 val zero_again = frob [int] _
adamc@212	15
adamc@212	16 val main : unit -> page = fn () => <html><body>
adamc@212	17 {cdata hi_again}
adamc@212	18 </body></html>

Mercurial > urweb