Mercurial > urweb
view tests/specialize.ur @ 316:04ebfe929a98
Unpolyed a polymorphic function of two arguments
author | Adam Chlipala <adamc@hcoop.net> |
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date | Thu, 11 Sep 2008 10:14:59 -0400 |
parents | e21d0dddda09 |
children | 6a4e365db60c |
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datatype list a = Nil | Cons of a * list a fun isNil (t ::: Type) (ls : list t) : bool = case ls of Nil => True | Cons _ => False fun append (t ::: Type) (ls1 : list t) (ls2 : list t) : list t = case ls1 of Nil => ls2 | Cons (x, ls1') => Cons (x, append ls1' ls2) fun delist (ls : list string) : xml body [] [] = case ls of Nil => <body>Nil</body> | Cons (h, t) => <body>{cdata h} :: {delist t}</body> val ls = Cons ("X", Cons ("Y", Cons ("Z", Nil))) val ls' = Cons ("A", Cons ("B", Nil)) fun main () : transaction page = return <html><body> {if isNil ls then <body>It's Nil.</body> else <body>It's not Nil.</body>} <p>{delist (append ls' ls)}</p> </body></html>