Mercurial > urweb
view demo/list.ur @ 1481:3061d1bf4b2d
recToList
author | Robin Green <greenrd@greenrd.org> |
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date | Mon, 27 Jun 2011 21:36:32 +0100 |
parents | 669ac5e9a69e |
children |
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datatype list t = Nil | Cons of t * list t fun length [t] (ls : list t) = let fun length' (ls : list t) (acc : int) = case ls of Nil => acc | Cons (_, ls') => length' ls' (acc + 1) in length' ls 0 end fun rev [t] (ls : list t) = let fun rev' (ls : list t) (acc : list t) = case ls of Nil => acc | Cons (x, ls') => rev' ls' (Cons (x, acc)) in rev' ls Nil end