--- pl:prolog:pllib:backward-chaining_rule_interpreter [2019/06/27 15:50]
+++ pl:prolog:pllib:backward-chaining_rule_interpreter [2019/06/27 15:50] (aktualna)
@@ Linia 1: / Linia 1: @@
+====== Backward-chaining rule interpreter ======
+{{tag>backward-chaining rules interpreter}}
+===== Description =====
+A backward chaining interpreter for if-then rules.
+**Source**:  PROLOG programming for artificial intelligence, 3rd Edition, Harlow, 2001, ISBN 0-201-40375-7.
+===== Download =====
+Program source code: {{backward-chaining_rule_interpreter.pl}}
+===== Listing =====
+<code prolog>
+%  Figure 15.6   A backward chaining interpreter for if-then rules.
+% A simple backward chaining rule interpreter
+:-  op( 800, fx, if).
+:-  op( 700, xfx, then).
+:-  op( 300, xfy, or).
+:-  op( 200, xfy, and).
+is_true( P)  :-
+   fact( P).
+is_true( P)  :-
+   if Condition then P,        % A relevant rule
+   is_true( Condition).        % whose condition is true
+is_true( P1 and P2)  :-
+   is_true( P1),
+   is_true( P2).
+is_true( P1 or P2)  :-
+   is_true( P1)
+   ;
+   is_true( P2).
+</code>
+===== Comments =====

pl/prolog/pllib/backward-chaining_rule_interpreter.txt · ostatnio zmienione: 2019/06/27 15:50 (edycja zewnętrzna)

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