annotate src/list_util.sml @ 19:e634ae817a8e

Testing constructor equivalences
author Adam Chlipala <adamc@hcoop.net>
date Sun, 08 Jun 2008 14:42:12 -0400
parents 38bf996e1c2e
children bfa2e9ae4df8
rev   line source
adamc@5 1 (* Copyright (c) 2008, Adam Chlipala
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adamc@5 26 *)
adamc@5 27
adamc@5 28 structure ListUtil :> LIST_UTIL = struct
adamc@5 29
adamc@5 30 fun mapfoldl f i =
adamc@5 31 let
adamc@5 32 fun mf s ls' ls =
adamc@5 33 case ls of
adamc@5 34 nil => (s, rev ls')
adamc@5 35 | h :: t =>
adamc@5 36 let
adamc@5 37 val (s, h') = f (h, s)
adamc@5 38 in
adamc@5 39 mf s (h' :: ls') t
adamc@5 40 end
adamc@5 41 in
adamc@5 42 mf i []
adamc@5 43 end
adamc@5 44
adamc@6 45 structure S = Search
adamc@6 46
adamc@6 47 fun mapfold f =
adamc@6 48 let
adamc@6 49 fun mf ls s =
adamc@6 50 case ls of
adamc@6 51 nil => S.Continue (nil, s)
adamc@6 52 | h :: t =>
adamc@6 53 case f h s of
adamc@6 54 S.Return x => S.Return x
adamc@6 55 | S.Continue (h', s) =>
adamc@6 56 case mf t s of
adamc@6 57 S.Return x => S.Return x
adamc@6 58 | S.Continue (t', s) => S.Continue (h' :: t', s)
adamc@6 59 in
adamc@6 60 mf
adamc@6 61 end
adamc@6 62
adamc@5 63 end