1/* Part of Extended Libraries for SWI-Prolog 2 3 Author: Edison Mera 4 E-mail: efmera@gmail.com 5 WWW: https://github.com/edisonm/xlibrary 6 Copyright (C): 2015, Process Design Center, Breda, The Netherlands. 7 All rights reserved. 8 9 Redistribution and use in source and binary forms, with or without 10 modification, are permitted provided that the following conditions 11 are met: 12 13 1. Redistributions of source code must retain the above copyright 14 notice, this list of conditions and the following disclaimer. 15 16 2. Redistributions in binary form must reproduce the above copyright 17 notice, this list of conditions and the following disclaimer in 18 the documentation and/or other materials provided with the 19 distribution. 20 21 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 29 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 31 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32 POSSIBILITY OF SUCH DAMAGE. 33*/ 34 35:- module(abstract_slicer, 36 [abstract_slice/3, 37 abstract_slice/4, 38 apply_mode/5, 39 slicer_abstraction/7]). 40 41:- use_module(library(apply)). 42:- use_module(library(option)). 43:- use_module(library(pure)). 44:- use_module(library(abstract_interpreter)). 45:- use_module(library(terms_share)). 46 47:- meta_predicate 48 abstract_slice(,,), 49 abstract_slice(,,,), 50 slicer_abstraction(,,,,, ,).
59abstract_slice(M:Head, Mode, OptL) :-
60 abstract_slice(M:Head, Mode, OptL, _).Example:
consider the next predicate:
popt('option'(A), []) :- member(A, [1,2,3]).
popt('option 1', Answer) :- append(_,_,Answer).
popt('option 2', Answer) :- member(Answer, [1,2,3]).
popt('option 3', []) :- member(_Answer, [1,2,3]).
If we just execute the predicate with Answer uninstatiated, we will get infinite solutions, but:
?- abstract_slice(popt(A,X),[+,?],[]). A = option(1) ; A = option(2) ; A = option(3) ; A = 'option 1' ; A = 'option 2' ; A = 'option 3'.
Will 'abstract' the execution of popt/2 to get all the matches of A, slicing out X
95abstract_slice(M:Head, Mode, OptL, State) :- 96 apply_mode(Head, Mask, Mode, Spec, RevS), 97 term_variables(RevS, VarsR), 98 option(eval_scope(Scope), OptL, body), 99 abstract_interpreter(M:Mask, slicer_abstraction(Spec, VarsR, Scope), OptL, State), 100 % In Mask the output arguments are variable, so the binding is performed 101 % after the abstract interpretation. This is a bit inefficient, but correct: 102 Head = Mask. 103 104apply_mode(Call, Mask, Mode, Spec, RevS) :- 105 functor(Call, F, A), 106 functor(Mask, F, A), 107 functor(Spec, F, A), 108 functor(RevS, F, A), 109 apply_mode_arg(1, Call, Mask, Mode, Spec, RevS). 110 111apply_mode_arg(N1, Call, Mask, Mode, Spec, RevS) :- 112 arg(N1, Call, Arg), !, 113 arg(N1, Mask, Var), 114 arg(N1, Mode, MSp), 115 arg(N1, Spec, ASp), 116 arg(N1, RevS, ARs), 117 ( MSp = - 118 ->ASp = Var, 119 ARs = - 120 ; ASp = +, 121 ARs = Arg, 122 Arg = Var 123 ), 124 succ(N1, N), 125 apply_mode_arg(N, Call, Mask, Mode, Spec, RevS). 126apply_mode_arg(_, _, _, _, _, _). 127 128chain_of_dependencies(Spec, VarsR, Goal, ContL) :- 129 \+ ground(Goal), 130 ( terms_share(Spec, VarsR, Goal) 131 ->true 132 ; select(Cont, ContL, ContL2), 133 terms_share(Cont, VarsR, Goal), 134 chain_of_dependencies(Spec, VarsR, Cont, ContL2) 135 ), 136 !. 137 138slicer_abstraction(Spec, VarsR, Scope, MGoal, Body) --> 139 {predicate_property(MGoal, interpreted)}, 140 !, 141 {strip_module(MGoal, M, Goal)}, 142 get_state(state(Loc1, EvalL, OnErr, CallL, Data, Cont, Result1)), 143 { \+ ground(Spec), 144 chain_of_dependencies(Spec, VarsR, Goal, Cont) 145 ->match_head_body(M:Goal, Body1, Loc), 146 ( Scope = body 147 ->( terms_share(Spec, VarsR, Goal) 148 ->Body = Body1 149 ; Body1 = CM:Body2, 150 Body = CM:once(Body2) 151 ) 152 ; terms_share(Spec, VarsR, Goal) 153 ->Body = Body1 154 ; Body = M:true 155 ) 156 ; % check if the body trivially fails: 157 ( Scope = body 158 ->once(( match_head_body(M:Goal, Body1, Loc), 159 % if no side effects, increase precision executing the body: 160 ( is_pure_body(Body1) 161 ->call(Body1) 162 ; true 163 ) 164 )) 165 ; Loc = Loc1 166 ), 167 Body = M:true 168 }, 169 { Scope = head 170 ->Result = bottom % Kludge to avoid cut remove solutions 171 ; Result = Result1 172 }, 173 put_state(state(Loc, EvalL, OnErr, CallL, Data, Cont, Result)). 174slicer_abstraction(_, _, _, MGoal, M:true) --> 175 get_state(state(Loc, _, OnError, CallL, _, _, _)), 176 { call(OnError, error(existence_error(evaluation_rule, MGoal), Loc)), 177 call(OnError, call_stack(CallL)), 178 strip_module(MGoal, M, _) 179 }, 180 bottom. 181 182prologmessage(call_stack(CallL)) --> foldl(call_at, CallL). 183 184call_at(Call-Loc) --> 185 [" "], '$messages':swi_location(Loc), ["~q"-[Call], nl]
Abstract slicer
Implements the next abstract domain: find possible matches of output arguments of the given predicate.
*/