adamc@5: (* Copyright (c) 2008, Adam Chlipala
adamc@5:  * All rights reserved.
adamc@5:  *
adamc@5:  * Redistribution and use in source and binary forms, with or without
adamc@5:  * modification, are permitted provided that the following conditions are met:
adamc@5:  *
adamc@5:  * - Redistributions of source code must retain the above copyright notice,
adamc@5:  *   this list of conditions and the following disclaimer.
adamc@5:  * - Redistributions in binary form must reproduce the above copyright notice,
adamc@5:  *   this list of conditions and the following disclaimer in the documentation
adamc@5:  *   and/or other materials provided with the distribution.
adamc@5:  * - The names of contributors may not be used to endorse or promote products
adamc@5:  *   derived from this software without specific prior written permission.
adamc@5:  *
adamc@5:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@5:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@5:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@5:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@5:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
adamc@5:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@5:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@5:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@5:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@5:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@5:  * POSSIBILITY OF SUCH DAMAGE.
adamc@5:  *)
adamc@5: 
adamc@5: structure ListUtil :> LIST_UTIL = struct
adamc@5: 
adamc@6: structure S = Search
adamc@6: 
adamc@110: fun mapConcat f =
adamc@110:     let
adamc@110:         fun mc acc ls =
adamc@110:             case ls of
adamc@110:                 [] => rev acc
adamc@110:               | h :: t => mc (List.revAppend (f h, acc)) t
adamc@110:     in
adamc@110:         mc []
adamc@110:     end
adamc@110: 
adamc@6: fun mapfold f =
adamc@6:     let
adamc@6:         fun mf ls s =
adamc@6:             case ls of
adamc@6:                 nil => S.Continue (nil, s)
adamc@6:               | h :: t =>
adamc@6:                 case f h s of
adamc@6:                     S.Return x => S.Return x
adamc@6:                   | S.Continue (h', s) =>
adamc@6:                     case mf t s of
adamc@6:                         S.Return x => S.Return x
adamc@6:                       | S.Continue (t', s) => S.Continue (h' :: t', s)
adamc@6:     in
adamc@6:         mf
adamc@6:     end
adamc@6: 
adamc@34: fun mapfoldB f =
adamc@34:     let
adamc@34:         fun mf ctx ls s =
adamc@34:             case ls of
adamc@34:                 nil => S.Continue (nil, s)
adamc@34:               | h :: t =>
adamc@34:                 let
adamc@34:                     val (ctx, r) = f (ctx, h)
adamc@34:                 in
adamc@34:                     case r s of
adamc@34:                         S.Return x => S.Return x
adamc@34:                       | S.Continue (h', s) =>
adamc@34:                         case mf ctx t s of
adamc@34:                             S.Return x => S.Return x
adamc@34:                           | S.Continue (t', s) => S.Continue (h' :: t', s)
adamc@34:                 end
adamc@34:     in
adamc@34:         mf
adamc@34:     end
adamc@34: 
adamc@26: fun foldlMap f s =
adamc@26:     let
adamc@26:         fun fm (ls', s) ls =
adamc@26:             case ls of
adamc@26:                 nil => (rev ls', s)
adamc@26:               | h :: t =>
adamc@26:                 let
adamc@26:                     val (h', s') = f (h, s)
adamc@26:                 in
adamc@26:                     fm (h' :: ls', s') t
adamc@26:                 end
adamc@26:     in
adamc@26:         fm ([], s)
adamc@26:     end
adamc@26: 
adamc@39: fun foldlMapConcat f s =
adamc@39:     let
adamc@39:         fun fm (ls', s) ls =
adamc@39:             case ls of
adamc@39:                 nil => (rev ls', s)
adamc@39:               | h :: t =>
adamc@39:                 let
adamc@39:                     val (h', s') = f (h, s)
adamc@39:                 in
adamc@39:                     fm (List.revAppend (h', ls'), s') t
adamc@39:                 end
adamc@39:     in
adamc@39:         fm ([], s)
adamc@39:     end
adamc@39: 
adamc@39: fun foldlMapPartial f s =
adamc@39:     let
adamc@39:         fun fm (ls', s) ls =
adamc@39:             case ls of
adamc@39:                 nil => (rev ls', s)
adamc@39:               | h :: t =>
adamc@39:                 let
adamc@39:                     val (h', s') = f (h, s)
adamc@39:                     val ls' = case h' of
adamc@39:                                   NONE => ls'
adamc@39:                                 | SOME h' => h' :: ls'
adamc@39:                 in
adamc@39:                     fm (ls', s') t
adamc@39:                 end
adamc@39:     in
adamc@39:         fm ([], s)
adamc@39:     end
adamc@39: 
adamc@849: fun foldlMapiPartial f s =
adamc@849:     let
adamc@849:         fun fm (n, ls', s) ls =
adamc@849:             case ls of
adamc@849:                 nil => (rev ls', s)
adamc@849:               | h :: t =>
adamc@849:                 let
adamc@849:                     val (h', s') = f (n, h, s)
adamc@849:                     val ls' = case h' of
adamc@849:                                   NONE => ls'
adamc@849:                                 | SOME h' => h' :: ls'
adamc@849:                 in
adamc@849:                     fm (n + 1, ls', s') t
adamc@849:                 end
adamc@849:     in
adamc@849:         fm (0, [], s)
adamc@849:     end
adamc@849: 
adamc@847: fun foldlMapAbort f s =
adamc@847:     let
adamc@847:         fun fm (ls', s) ls =
adamc@847:             case ls of
adamc@847:                 nil => SOME (rev ls', s)
adamc@847:               | h :: t =>
adamc@847:                 case f (h, s) of
adamc@847:                     NONE => NONE
adamc@847:                   | SOME (h', s') => fm (h' :: ls', s') t
adamc@847:     in
adamc@847:         fm ([], s)
adamc@847:     end
adamc@847: 
adamc@23: fun search f =
adamc@23:     let
adamc@23:         fun s ls =
adamc@23:             case ls of
adamc@23:                 [] => NONE
adamc@23:               | h :: t =>
adamc@23:                 case f h of
adamc@23:                     NONE => s t
adamc@23:                   | v => v
adamc@23:     in
adamc@23:         s
adamc@23:     end
adamc@23: 
adamc@839: fun searchi f =
adamc@839:     let
adamc@839:         fun s n ls =
adamc@839:             case ls of
adamc@839:                 [] => NONE
adamc@839:               | h :: t =>
adamc@839:                 case f (n, h) of
adamc@839:                     NONE => s (n + 1) t
adamc@839:                   | v => v
adamc@839:     in
adamc@839:         s 0
adamc@839:     end
adamc@839: 
adamc@120: fun mapi f =
adamc@120:     let
adamc@120:         fun m i acc ls =
adamc@120:             case ls of
adamc@120:                 [] => rev acc
adamc@120:               | h :: t => m (i + 1) (f (i, h) :: acc) t
adamc@120:     in
adamc@120:         m 0 []
adamc@120:     end
adamc@120: 
adamc@849: fun mapiPartial f =
adamc@849:     let
adamc@849:         fun m i acc ls =
adamc@849:             case ls of
adamc@849:                 [] => rev acc
adamc@849:               | h :: t =>
adamc@849:                 m (i + 1) (case f (i, h) of
adamc@849:                                NONE => acc
adamc@849:                              | SOME v => v :: acc) t
adamc@849:     in
adamc@849:         m 0 []
adamc@849:     end
adamc@849: 
adamc@792: fun appi f =
adamc@792:     let
adamc@792:         fun m i ls =
adamc@792:             case ls of
adamc@792:                 [] => ()
adamc@792:               | h :: t => (f (i, h); m (i + 1) t)
adamc@792:     in
adamc@792:         m 0
adamc@792:     end
adamc@792: 
adamc@191: fun foldli f =
adamc@191:     let
adamc@191:         fun m i acc ls =
adamc@191:             case ls of
adamc@191:                 [] => acc
adamc@191:               | h :: t => m (i + 1) (f (i, h, acc)) t
adamc@191:     in
adamc@191:         m 0
adamc@191:     end
adamc@191: 
adamc@275: fun foldri f i ls =
adamc@275:     let
adamc@275:         val len = length ls
adamc@275:     in
adamc@275:         foldli (fn (n, x, s) => f (len - n - 1, x, s)) i (rev ls)
adamc@275:     end
adamc@275: 
adamc@313: fun foldliMap f s =
adamc@313:     let
adamc@313:         fun fm (n, ls', s) ls =
adamc@313:             case ls of
adamc@313:                 nil => (rev ls', s)
adamc@313:               | h :: t =>
adamc@313:                 let
adamc@313:                     val (h', s') = f (n, h, s)
adamc@313:                 in
adamc@313:                     fm (n + 1, h' :: ls', s') t
adamc@313:                 end
adamc@313:     in
adamc@313:         fm (0, [], s)
adamc@313:     end
adamc@313: 
adamc@792: fun appn f n =
adamc@792:     let
adamc@792:         fun iter m =
adamc@792:             if m >= n then
adamc@792:                 ()
adamc@792:             else
adamc@792:                 (f m;
adamc@792:                  iter (m + 1))
adamc@792:     in
adamc@792:         iter 0
adamc@792:     end
adamc@792: 
adamc@5: end