listmap.pl

   1 /*  $Id$
   2
   3     Part of CHR (Constraint Handling Rules)
   4
   5     Author:        Tom Schrijvers
   6     E-mail:        Tom.Schrijvers@cs.kuleuven.ac.be
   7     WWW:           http://www.swi-prolog.org
   8     Copyright (C): 2003-2004, K.U. Leuven
   9
  10     This program is free software; you can redistribute it and/or
  11     modify it under the terms of the GNU General Public License
  12     as published by the Free Software Foundation; either version 2
  13     of the License, or (at your option) any later version.
  14
  15     This program is distributed in the hope that it will be useful,
  16     but WITHOUT ANY WARRANTY; without even the implied warranty of
  17     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18     GNU General Public License for more details.
  19
  20     You should have received a copy of the GNU Lesser General Public
  21     License along with this library; if not, write to the Free Software
  22     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23
  24     As a special exception, if you link this library with other files,
  25     compiled with a Free Software compiler, to produce an executable, this
  26     library does not by itself cause the resulting executable to be covered
  27     by the GNU General Public License. This exception does not however
  28     invalidate any other reasons why the executable file might be covered by
  29     the GNU General Public License.
  30 */
  31
  32 :- module(listmap,
  33         [
  34                 listmap_empty/1,
  35                 listmap_lookup/3,
  36                 listmap_insert/4,
  37                 listmap_remove/3,
  38                 listmap_merge/5
  39         ]).
  40
  41 listmap_empty([]).
  42
  43 listmap_lookup([K-V|R],Key,Q) :-
  44         ( Key == K ->
  45                 Q = V
  46         ;
  47                 Key @> K,
  48                 listmap_lookup(R,Key,Q)
  49         ).
  50
  51 listmap_insert([],Key,Value,[Key-Value]).
  52 listmap_insert([P|R],Key,Value,ML) :-
  53         P = K-_,
  54         compare(C,Key,K),
  55         ( C == (=) ->
  56                 ML = [K-Value|R]
  57         ; C == (<) ->
  58                 ML = [Key-Value,P|R]
  59         ;
  60                 ML = [P|Tail],
  61                 listmap_insert(R,Key,Value,Tail)
  62         ).
  63
  64 listmap_merge(ML1,ML2,F,G,ML) :-
  65         ( ML1 == [] ->
  66                 ML = ML2
  67         ; ML2 == [] ->
  68                 ML = ML1
  69         ;
  70                 ML1 = [P1|R1], P1 = K1-V1,
  71                 ML2 = [P2|R2], P2 = K2-V2,
  72                 compare(C,K1,K2),
  73                 ( C == (=) ->
  74                         Call =.. [F,V1,V2,NV],
  75                         call(Call),
  76                         ML = [K1-NV|Tail],
  77                         listmap_merge(R1,R2,F,G,Tail)
  78                 ; C == (<) ->
  79                         Call =.. [G,V1,NV],
  80                         call(Call),
  81                         ML = [K1-NV|Tail],
  82                         listmap_merge(R1,ML2,F,G,Tail)
  83                 ;
  84                         Call =.. [G,V2,NV],
  85                         call(Call),
  86                         ML = [K2-NV|Tail],
  87                         listmap_merge(ML1,R2,F,G,Tail)
  88                 )
  89         ).
  90
  91
  92 listmap_remove([],_,[]).
  93 listmap_remove([P|R],Key,NLM) :-
  94         P = K-_,
  95         compare(C,Key,K),
  96         ( C == (=) ->
  97                 NLM = R
  98         ; C == (<) ->
  99                 NLM = [P|R]
 100         ;
 101                 NLM = [P|Tail],
 102                 listmap_remove(R,Key,Tail)
 103         ).
 104
 105