Mercurial > urweb

annotate tests/specialize.ur @ 399:2d64457eedb1

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
listFun uses length
author Adam Chlipala <adamc@hcoop.net>
date Tue, 21 Oct 2008 13:41:03 -0400
parents 60907c06b4c4
children
rev   line source
adamc@315 1 datatype list a = Nil | Cons of a * list a
adamc@315 2
adamc@315 3 fun isNil (t ::: Type) (ls : list t) : bool =
adamc@315 4 case ls of
adamc@315 5 Nil => True
adamc@315 6 | Cons _ => False
adamc@315 7
adamc@316 8 fun append (t ::: Type) (ls1 : list t) (ls2 : list t) : list t =
adamc@315 9 case ls1 of
adamc@315 10 Nil => ls2
adamc@315 11 | Cons (x, ls1') => Cons (x, append ls1' ls2)
adamc@315 12
adamc@317 13 fun pairAppend (t1 ::: Type) (t2 ::: Type) (ls1 : list (t1 * t2)) (ls2 : list (t1 * t2)) : list (t1 * t2) =
adamc@317 14 case ls1 of
adamc@317 15 Nil => ls2
adamc@317 16 | Cons (x, ls1') => Cons (x, pairAppend ls1' ls2)
adamc@317 17
adamc@315 18 fun delist (ls : list string) : xml body [] [] =
adamc@315 19 case ls of
adamc@315 20 Nil => <body>Nil</body>
adamc@316 21 | Cons (h, t) => <body>{cdata h} :: {delist t}</body>
adamc@315 22
adamc@317 23 fun pairDelist (ls : list (string * int)) : xml body [] [] =
adamc@317 24 case ls of
adamc@317 25 Nil => <body>Nil</body>
adamc@317 26 | Cons ((s, n), t) => <body>({cdata s}, {cdata (show _ n)}) :: {pairDelist t}</body>
adamc@317 27
adamc@315 28 val ls = Cons ("X", Cons ("Y", Cons ("Z", Nil)))
adamc@316 29 val ls' = Cons ("A", Cons ("B", Nil))
adamc@315 30
adamc@317 31 val pls = Cons (("X", 1), Cons (("Y", 2), Cons (("Z", 3), Nil)))
adamc@317 32 val pls' = Cons (("A", 1), Cons (("B", 2), Nil))
adamc@317 33
adamc@315 34 fun main () : transaction page = return <html><body>
adamc@315 35 {if isNil ls then <body>It's Nil.</body> else <body>It's not Nil.</body>}
adamc@316 36
adamc@316 37 <p>{delist (append ls' ls)}</p>
adamc@317 38
adamc@317 39 <p>{pairDelist (pairAppend pls' pls)}</p>
adamc@315 40 </body></html>