92 lines
2.3 KiB
C
92 lines
2.3 KiB
C
/*************************************************************************
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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: sbaunify.h *
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* Last rev: *
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* mods: *
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* comments: Basic abstract machine operations, such as *
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* dereferencing, binding, trailing, and unification *
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* in the SBA model. *
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* *
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*************************************************************************/
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#ifdef SCCS
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static char SccsId[] = "%W% %G%";
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#endif /* SCCS */
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/************************************************************
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Unification Routines
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*************************************************************/
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static inline
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Int bind_variable(Term t0, Term t1)
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{
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tr_fr_ptr TR0 = TR;
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if (_YAP_IUnify(t0,t1)) {
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return(TRUE);
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} else {
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while(TR != TR0) {
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CELL *p = (CELL *)TrailTerm(--TR);
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RESET_VARIABLE(p);
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}
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return(FALSE);
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}
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}
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EXTERN inline
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/*
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Int unify(Term t0, Term t1)
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*/
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Int unify(Term t0, Term t1)
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{
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tr_fr_ptr TR0 = TR;
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if (_YAP_IUnify(t0,t1)) {
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return(TRUE);
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} else {
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while(TR != TR0) {
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CELL *p = (CELL *)TrailTerm(--TR);
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RESET_VARIABLE(p);
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}
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return(FALSE);
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}
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}
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EXTERN inline Int unify_constant(register Term a, register Term cons)
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{
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CELL *pt;
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deref_head(a,unify_cons_unk);
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unify_cons_nonvar:
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{
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if (a == cons) return(TRUE);
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else if (IsApplTerm(a) && IsExtensionFunctor(FunctorOfTerm(a))) {
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Functor fun = FunctorOfTerm(a);
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if (fun == FunctorDouble)
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return(IsFloatTerm(cons) && FloatOfTerm(a) == FloatOfTerm(cons));
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else if (fun == FunctorLongInt) {
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return(IsLongIntTerm(cons) && LongIntOfTerm(a) == LongIntOfTerm(cons));
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#ifdef TERM_EXTENSIONS
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} else if (IsAttachFunc(fun)) {
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return(attas[ExtFromFunctor(fun)].bind_op(SBIND,a,cons));
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#endif /* TERM_EXTENSIONS */
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} else
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return(FALSE);
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/* no other factors are accepted as arguments */
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} else return(FALSE);
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}
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deref_body(a,pt,unify_cons_unk,unify_cons_nonvar);
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Bind(pt,cons);
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return(TRUE);
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}
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