| 1 | |
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| 2 | :- category(solver). |
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| 3 | |
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| 4 | :- info([ |
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| 5 | version is 1.1, |
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| 6 | date is 2008/10/2, |
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| 7 | author is 'Paulo Moura', |
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| 8 | comment is 'Simple meta-interpreter for pure Prolog with only conjunctions as clause bodies.']). |
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| 9 | |
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| 10 | :- public(solve/1). |
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| 11 | :- mode(solve(+goal), zero_or_more). |
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| 12 | :- info(solve/1, [ |
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| 13 | comment is 'Proves goal.', |
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| 14 | argnames is ['Goal']]). |
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| 15 | |
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| 16 | solve(true) :- |
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| 17 | !. |
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| 18 | solve((A, B)) :- |
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| 19 | !, |
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| 20 | solve(A), |
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| 21 | solve(B). |
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| 22 | solve(A) :- |
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| 23 | clause(A, B), % retrieves clauses in "this", i.e. in the database of the object importing the category |
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| 24 | solve(B). |
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| 25 | |
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| 26 | :- end_category. |
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| 27 | |
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| 28 | |
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| 29 | :- category(proof_tree). |
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| 30 | |
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| 31 | :- info([ |
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| 32 | version is 1.1, |
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| 33 | date is 2008/10/2, |
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| 34 | author is 'Paulo Moura', |
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| 35 | comment is 'Meta-interpreter for pure Prolog with only conjunctions as clause bodies.']). |
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| 36 | |
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| 37 | :- public(proof_tree/2). |
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| 38 | :- mode(proof_tree(+goal, -tree), zero_or_more). |
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| 39 | :- info(proof_tree/2, [ |
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| 40 | comment is 'Constructs a proof tree for a goal.', |
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| 41 | argnames is ['Goal', 'Tree']]). |
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| 42 | |
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| 43 | proof_tree(true, true) :- |
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| 44 | !. |
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| 45 | proof_tree((A, B), (PA, PB)) :- |
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| 46 | !, |
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| 47 | proof_tree(A, PA), |
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| 48 | proof_tree(B, PB). |
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| 49 | proof_tree(A, (A :- PB)) :- |
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| 50 | clause(A, B), % retrieves clauses in "this", i.e. in the database of the object importing the category |
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| 51 | proof_tree(B, PB). |
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| 52 | |
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| 53 | :- end_category. |
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| 54 | |
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| 55 | |
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| 56 | :- category(tracer). |
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| 57 | |
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| 58 | :- info([ |
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| 59 | version is 1.1, |
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| 60 | date is 2008/10/2, |
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| 61 | author is 'Paulo Moura', |
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| 62 | comment is 'A simple tracer meta-interpreter for pure Prolog with only conjunctions as clause bodies.']). |
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| 63 | |
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| 64 | :- public(trace/1). |
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| 65 | :- mode(trace(+goal), zero_or_more). |
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| 66 | :- info(trace/1, [ |
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| 67 | comment is 'Traces goal proof.', |
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| 68 | argnames is ['Goal']]). |
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| 69 | |
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| 70 | trace(Goal) :- |
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| 71 | trace(Goal, 1). |
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| 72 | |
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| 73 | trace(true, _) :- |
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| 74 | !. |
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| 75 | trace((A, B), Depth) :- |
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| 76 | !, |
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| 77 | trace(A, Depth), |
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| 78 | trace(B, Depth). |
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| 79 | trace(A, Depth) :- |
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| 80 | write_trace(call, A, Depth), |
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| 81 | clause(A, B), % retrieves clauses in "this", i.e. in the database of the object importing the category |
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| 82 | Depth2 is Depth + 1, |
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| 83 | trace(B, Depth2), |
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| 84 | ( write_trace(exit, A, Depth) |
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| 85 | ; write_trace(redo, A, Depth), |
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| 86 | fail |
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| 87 | ). |
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| 88 | trace(A, Depth) :- |
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| 89 | write_trace(fail, A, Depth), |
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| 90 | fail. |
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| 91 | |
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| 92 | write_trace(Port, Goal, Depth) :- |
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| 93 | write(Depth), write(' '), write(Port), write(': '), writeq(Goal), nl. |
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| 94 | |
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| 95 | :- end_category. |
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