diogo/yap-6.3
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in tabled mode, replace X is Y by X=X', is(Y') to avoid cases where Y is assigned determinastically but needs to be later restored. (obs Ricardo Rocha)

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Costa Vitor 2009-07-22 14:23:32 -05:00
parent c1024caa53
commit ead58f6b34
1 changed files with 10 additions and 4 deletions
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14
pl/arith.yap
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@ -86,8 +86,7 @@ do_not_compile_expressions :- set_value('$c_arith',[]).
number(Y),
P = ( X = Y); % This case reduces to an unification
'$expand_expr'(Y, P0, X0),
'$drop_is'(X0, X, P1),
'$do_and'(P0, P1, P)
'$drop_is'(X0, X, P0, P)
).
'$do_c_built_in'(Comp0, _, R) :- % now, do it for comparisons
'$compop'(Comp0, Op, E, F),
@ -116,8 +115,15 @@ do_not_compile_expressions :- set_value('$c_arith',[]).
% V is the result of the simplification,
% X the result of the initial expression
% and the last argument is how we are writing this result
'$drop_is'(V, V, true) :- var(V), !. % usual case
'$drop_is'(V, X, X is V). % atoms
'$drop_is'(V, V1, P0, G) :- var(V), !, % usual case
('$undefined'('$c_table'(_,_), prolog) ->
V = V1, P0 = G
;
'$do_and'(V = V1,P0,G)
).
'$drop_is'(V, X, P0, P) :- % atoms
'$do_and'(P1, X is V, P).
% Table of arithmetic comparisons
'$compop'(X < Y, < , X, Y).