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(* Copyright (c) 2008, Adam Chlipala
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - The names of contributors may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*)
structure ListUtil :> LIST_UTIL = struct
fun mapfoldl f i =
let
fun mf s ls' ls =
case ls of
nil => (s, rev ls')
| h :: t =>
let
val (s, h') = f (h, s)
in
mf s (h' :: ls') t
end
in
mf i []
end
structure S = Search
fun mapfold f =
let
fun mf ls s =
case ls of
nil => S.Continue (nil, s)
| h :: t =>
case f h s of
S.Return x => S.Return x
| S.Continue (h', s) =>
case mf t s of
S.Return x => S.Return x
| S.Continue (t', s) => S.Continue (h' :: t', s)
in
mf
end
fun search f =
let
fun s ls =
case ls of
[] => NONE
| h :: t =>
case f h of
NONE => s t
| v => v
in
s
end
end
|
