annotate demo/list.ur @ 416:679b2fbbd4d0

Counter demo
author Adam Chlipala <adamc@hcoop.net>
date Thu, 23 Oct 2008 11:59:48 -0400
parents 4d519baf357c
children 7ef4b2911b09
rev   line source
adamc@397 1 datatype list t = Nil | Cons of t * list t
adamc@397 2
adamc@397 3 fun length' (t ::: Type) (ls : list t) (acc : int) =
adamc@397 4 case ls of
adamc@397 5 Nil => acc
adamc@397 6 | Cons (_, ls') => length' ls' (acc + 1)
adamc@397 7
adamc@397 8 fun length (t ::: Type) (ls : list t) = length' ls 0
adamc@397 9
adamc@397 10 fun rev' (t ::: Type) (ls : list t) (acc : list t) =
adamc@397 11 case ls of
adamc@397 12 Nil => acc
adamc@397 13 | Cons (x, ls') => rev' ls' (Cons (x, acc))
adamc@397 14
adamc@397 15 fun rev (t ::: Type) (ls : list t) = rev' ls Nil