65 lines
1.5 KiB
Prolog
65 lines
1.5 KiB
Prolog
/*************************************************************************
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* *
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* YAP Prolog *
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* *
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* Yap Prolog was developed at NCCUP - Universidade do Porto *
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* *
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* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
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* *
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**************************************************************************
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* *
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* File: ground.pl *
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* Last rev: *
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* mods: *
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* comments: Variables and ground *
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* *
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*************************************************************************/
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/*
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% grounds all free variables
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% as terms of the form '$VAR'(N)
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numbervars('$VAR'(M), M, N) :- !,
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succ(M, N).
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numbervars(Atomic, M, M) :-
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atomic(Atomic), !.
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numbervars(Term, M, N) :-
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functor(Term, _, Arity),
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'$numbervars'(0,Arity, Term, M, N).
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'$numbervars'(A, A, _, N, N) :- !.
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'$numbervars'(A,Arity, Term, M, N) :-
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'$succ'(A,An),
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arg(An, Term, Arg),
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numbervars(Arg, M, K), !,
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'$numbervars'(An, Arity, Term, K, N).
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ground(Term) :-
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nonvar(Term), % This term is not a variable,
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functor(Term, _, Arity),
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'$ground'(Arity, Term). % and none of its arguments are.
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'$ground'(0, _) :- !.
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'$ground'(N, Term) :-
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'$predc'(N,M),
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arg(N, Term, ArgN),
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ground(ArgN),
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'$ground'(M, Term).
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numbervars(Term, M, N) :-
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'$variables_in_term'(Term, [], L),
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'$numbermarked_vars'(L, M, N).
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'$numbermarked_vars'([], M, M).
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'$numbermarked_vars'([V|L], M, N) :-
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attvar(V), !,
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'$numbermarked_vars'(L, M, N).
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'$numbermarked_vars'(['$VAR'(M)|L], M, N) :-
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M1 is M+1,
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'$numbermarked_vars'(L, M1, N).
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*/
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