108 lines
2.1 KiB
Plaintext
108 lines
2.1 KiB
Plaintext
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=================================================================
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Logtalk - Object oriented extension to Prolog
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Release 2.17.1
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Copyright (c) 1998-2004 Paulo Moura. All Rights Reserved.
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=================================================================
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% solver - a simple meta-interpreter for pure Prolog:
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| ?- solver::assertz(member_of(H, [H| _])).
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H = _G178
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yes
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| ?- solver::assertz((member_of(H, [_| T]) :- member_of(H, T))).
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H = _G181
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T = _G179
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yes
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| ?- solver::solve(member_of(2, [1,2,3])).
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yes
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| ?- solver::solve(member_of(X, [1,2,3])).
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X = 1 ;
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X = 2 ;
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X = 3
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yes
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% proof_tree - a simple meta-interpreter for pure Prolog that
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% construct a proof tree:
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| ?- proof_tree::assertz(member_of(H, [H| _])).
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H = _G178
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yes
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| ?- proof_tree::assertz((member_of(H, [_| T]) :- member_of(H, T))).
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H = _G181
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T = _G179
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yes
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| ?- proof_tree::solve(member_of(2, [1,2,3]), Tree).
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Tree = member_of(2, [1, 2, 3]):- (member_of(2, [2, 3]):-true)
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yes
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% tracer - a simple meta-interpreter for tracing goal proofs
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% using pure Prolog:
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| ?- tracer::assertz(member_of(H, [H| _])).
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H = _G178
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yes
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| ?- tracer::assertz((member_of(H, [_| T]) :- member_of(H, T))).
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H = _G181
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T = _G179
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yes
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| ?- tracer::trace(member_of(3, [1,2,3])).
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1 call: member_of(3, [1, 2, 3])
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2 call: member_of(3, [2, 3])
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3 call: member_of(3, [3])
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3 exit: member_of(3, [3])
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2 exit: member_of(3, [2, 3])
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1 exit: member_of(3, [1, 2, 3])
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yes
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| ?- tracer::trace(member_of(X, [1,2,3])).
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1 call: member_of(_G187, [1, 2, 3])
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1 exit: member_of(1, [1, 2, 3])
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X = 1 ;
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1 redo: member_of(1, [1, 2, 3])
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2 call: member_of(_G187, [2, 3])
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2 exit: member_of(2, [2, 3])
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1 exit: member_of(2, [1, 2, 3])
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X = 2 ;
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1 redo: member_of(2, [1, 2, 3])
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2 redo: member_of(2, [2, 3])
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3 call: member_of(_G187, [3])
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3 exit: member_of(3, [3])
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2 exit: member_of(3, [2, 3])
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1 exit: member_of(3, [1, 2, 3])
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X = 3 ;
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1 redo: member_of(3, [1, 2, 3])
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2 redo: member_of(3, [2, 3])
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3 redo: member_of(3, [3])
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4 call: member_of(_G187, [])
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4 fail: member_of(_G187, [])
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3 fail: member_of(_G187, [3])
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2 fail: member_of(_G187, [2, 3])
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1 fail: member_of(_G187, [1, 2, 3])
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no
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