/************************************************************************* * * * YAP Prolog * * * * Yap Prolog was developed at NCCUP - Universidade do Porto * * * * Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 * * * ************************************************************************** * * * File: utilpreds.c * Last rev: 4/03/88 ** mods: * comments: new utility predicates for YAP * * * *************************************************************************/ /** * @file C/terms.c * * @brief applications of the tree walker pattern. * * @addtogroup Terms * * @{ * */ #include "absmi.h" #include "YapHeap.h" #include "attvar.h" #include "yapio.h" #ifdef HAVE_STRING_H #include "string.h" #endif static int expand_vts(int args USES_REGS) { UInt expand = LOCAL_Error_Size; yap_error_number yap_errno = LOCAL_Error_TYPE; LOCAL_Error_Size = 0; LOCAL_Error_TYPE = YAP_NO_ERROR; if (yap_errno == RESOURCE_ERROR_TRAIL) { /* Trail overflow */ if (!Yap_growtrail(expand, false)) { return false; } } else if (yap_errno == RESOURCE_ERROR_AUXILIARY_STACK) { /* Aux space overflow */ if (expand > 4 * 1024 * 1024) expand = 4 * 1024 * 1024; if (!Yap_ExpandPreAllocCodeSpace(expand, NULL, true)) { return false; } } else { if (!Yap_gcl(expand, 3, ENV, gc_P(P, CP))) { Yap_Error(RESOURCE_ERROR_STACK, TermNil, "in term_variables"); return false; } } return true; } static inline void clean_tr(tr_fr_ptr TR0 USES_REGS) { if (TR != TR0) { do { Term p = TrailTerm(--TR); RESET_VARIABLE(p); } while (TR != TR0); } } #if 0 static inline void clean_dirty_tr(tr_fr_ptr TR0 USES_REGS) { tr_fr_ptr pt0 = TR; while (pt0 != TR0) { Term p = TrailTerm(--pt0); if (IsApplTerm(p)) { CELL *pt = RepAppl(p); #ifdef FROZEN_STACKS pt[0] = TrailVal(pt0); #else pt[0] = TrailTerm(pt0 - 1); pt0--; #endif /* FROZEN_STACKS */ } else { RESET_VARIABLE(p); } } TR = TR0; } /// @brief recover original term while fixing direct refs. /// /// @param USES_REGS /// static inline void clean_complex_tr(tr_fr_ptr TR0 USES_REGS) { tr_fr_ptr pt0 = TR; while (pt0 != TR0) { Term p = TrailTerm(--pt0); if (IsApplTerm(p)) { /// pt: points to the address of the new term we may want to fix. CELL *pt = RepAppl(p); if (pt >= HB && pt < HR) { /// is it new? Term v = pt[0]; if (IsApplTerm(v)) { /// yes, more than a single ref *pt = (CELL)RepAppl(v); } #ifndef FROZEN_STACKS pt0--; #endif /* FROZEN_STACKS */ continue; } #ifdef FROZEN_STACKS pt[0] = TrailVal(pt0); #else pt[0] = TrailTerm(pt0 - 1); pt0--; #endif /* FROZEN_STACKS */ } else { RESET_VARIABLE(p); } } TR = TR0; } #endif typedef struct { Term old_var; Term new_var; } * vcell; typedef struct non_single_struct_t { CELL *ptd0; CELL d0; CELL *pt0, *pt0_end, *ptf; } non_singletons_t; #define WALK_COMPLEX_TERM__(LIST0, STRUCT0, PRIMI0) \ int lvl = push_text_stack(); \ \ struct non_single_struct_t *to_visit = Malloc( \ 1024 * sizeof(struct non_single_struct_t)), \ *to_visit0 = to_visit, \ *to_visit_max = to_visit + 1024; \ \ restart: \ while (pt0 < pt0_end) { \ register CELL d0; \ register CELL *ptd0; \ ++pt0; \ ptd0 = pt0; \ d0 = *ptd0; \ list_loop: \ deref_head(d0, var_in_term_unk); \ var_in_term_nvar : { \ if (IsPairTerm(d0)) { \ if (to_visit + 32 >= to_visit_max) { \ goto aux_overflow; \ } \ ptd0 = RepPair(d0); \ LIST0; \ if (*ptd0 == TermFreeTerm) \ goto restart; \ to_visit->pt0 = pt0; \ to_visit->pt0_end = pt0_end; \ to_visit->ptd0 = ptd0; \ to_visit->d0 = *ptd0; \ to_visit++; \ d0 = ptd0[0]; \ *ptd0 = TermFreeTerm; \ pt0 = ptd0; \ pt0_end = pt0 + 1; \ goto list_loop; \ } else if (IsApplTerm(d0)) { \ register Functor f; \ register CELL *ap2; \ /* store the terms to visit */ \ ptd0 = RepAppl(d0); \ f = (Functor)(d0 = *ptd0); \ \ if (to_visit + 32 >= to_visit_max) { \ goto aux_overflow; \ } \ STRUCT0; \ if (IsExtensionFunctor(f) || IsAtomTerm((CELL)f)) { \ \ goto restart; \ } \ to_visit->pt0 = pt0; \ to_visit->pt0_end = pt0_end; \ to_visit->ptd0 = ptd0; \ to_visit->d0 = d0; \ to_visit++; \ \ *ptd0 = TermNil; \ Term d1 = ArityOfFunctor(f); \ pt0 = ptd0; \ pt0_end = ptd0 + d1; \ goto restart; \ } else { \ PRIMI0; \ goto restart; \ } \ } \ derefa_body(d0, ptd0, var_in_term_unk, var_in_term_nvar); #define WALK_COMPLEX_TERM() WALK_COMPLEX_TERM__({}, {}, {}) #define END_WALK() } #define def_aux_overflow() \ aux_overflow : { \ size_t d1 = to_visit - to_visit0; \ size_t d2 = to_visit_max - to_visit0; \ to_visit0 = \ Realloc(to_visit0, (d2 + 128) * sizeof(struct non_single_struct_t)); \ to_visit = to_visit0 + d1; \ to_visit_max = to_visit0 + (d2 + 128); \ pt0--; \ } \ goto restart; #define def_trail_overflow() \ trail_overflow : { \ LOCAL_Error_TYPE = RESOURCE_ERROR_TRAIL; \ LOCAL_Error_Size = (TR - TR0) * sizeof(tr_fr_ptr *); \ clean_tr(TR0 PASS_REGS); \ HR = InitialH; \ pop_text_stack(lvl); \ return 0L; \ } #define def_global_overflow() \ global_overflow : { \ while (to_visit > to_visit0) { \ to_visit--; \ CELL *ptd0 = to_visit->ptd0; \ *ptd0 = to_visit->d0; \ } \ pop_text_stack(lvl); \ clean_tr(TR0 PASS_REGS); \ HR = InitialH; \ LOCAL_Error_TYPE = RESOURCE_ERROR_STACK; \ LOCAL_Error_Size = (ASP - HR) * sizeof(CELL); \ return false; \ } #define CYC_LIST \ if (*ptd0 == TermFreeTerm) { \ while (to_visit > to_visit0) { \ to_visit--; \ CELL *ptd0 = to_visit->ptd0; \ *ptd0 = to_visit->d0; \ } \ pop_text_stack(lvl); \ return true; \ } #define CYC_APPL \ if (IsAtomTerm((CELL)f)) { \ while (to_visit > to_visit0) { \ to_visit--; \ CELL *ptd0 = to_visit->ptd0; \ *ptd0 = to_visit->d0; \ } \ pop_text_stack(lvl); \ return true; \ } /** @brief routine to locate all variables in a term, and its applications */ static Term cyclic_complex_term(register CELL *pt0, register CELL *pt0_end USES_REGS) { WALK_COMPLEX_TERM__(CYC_LIST, CYC_APPL, {}); /* leave an empty slot to fill in later */ END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } pop_text_stack(lvl); return false; def_aux_overflow(); } bool Yap_IsCyclicTerm(Term t USES_REGS) { if (IsVarTerm(t)) { return false; } else if (IsPrimitiveTerm(t)) { return false; } else { return cyclic_complex_term(&(t)-1, &(t)PASS_REGS); } } /** @pred cyclic_term( + _T_ ) Succeeds if the graph representation of the term has loops. Say, the representation of a term `X` that obeys the equation `X=[X]` term has a loop from the list to its head. */ static Int cyclic_term(USES_REGS1) /* cyclic_term(+T) */ { return Yap_IsCyclicTerm(Deref(ARG1)); } /** @brief routine to locate all variables in a term, and its applications */ static bool ground_complex_term(register CELL *pt0, register CELL *pt0_end USES_REGS) { WALK_COMPLEX_TERM(); /* leave an empty slot to fill in later */ while (to_visit > to_visit0) { to_visit--; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; } pop_text_stack(lvl); return false; END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } pop_text_stack(lvl); return true; def_aux_overflow(); } bool Yap_IsGroundTerm(Term t) { CACHE_REGS if (IsVarTerm(t)) { return false; } else if (IsPrimitiveTerm(t)) { return true; } else { return ground_complex_term(&(t)-1, &(t)PASS_REGS); } } /** @pred ground( _T_) is iso Succeeds if there are no free variables in the term _T_. */ static Int ground(USES_REGS1) /* ground(+T) */ { return Yap_IsGroundTerm(Deref(ARG1)); } static Int var_in_complex_term(register CELL *pt0, register CELL *pt0_end, Term v USES_REGS) { WALK_COMPLEX_TERM(); if ((CELL)d0 == v) { /* we found it */ /* Do we still have compound terms to visit */ while (to_visit > to_visit0) { to_visit--; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; } pop_text_stack(lvl); return true; } END_WALK(); if (to_visit > to_visit0) { to_visit--; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; } pop_text_stack(lvl); return false; def_aux_overflow(); } static Int var_in_term(Term v, Term t USES_REGS) /* variables in term t */ { must_be_variable(v); t = Deref(t); if (IsVarTerm(t)) { return (v == t); } else if (IsPrimitiveTerm(t)) { return (false); } return (var_in_complex_term(&(t)-1, &(t), v PASS_REGS)); } /** @pred variable_in_term(? _Term_,? _Var_) Succeed if the second argument _Var_ is a variable and occurs in term _Term_. */ static Int variable_in_term(USES_REGS1) { return var_in_term(Deref(ARG2), Deref(ARG1) PASS_REGS); } /** * @brief routine to locate all variables in a term, and its applications. */ static Term vars_in_complex_term(register CELL *pt0, register CELL *pt0_end, Term inp USES_REGS) { register tr_fr_ptr TR0 = TR; CELL *InitialH = HR; CELL output = AbsPair(HR); WALK_COMPLEX_TERM(); /* do or pt2 are unbound */ *ptd0 = TermNil; /* leave an empty slot to fill in later */ if (HR + 1024 > ASP) { goto global_overflow; } HR[1] = AbsPair(HR + 2); HR += 2; HR[-2] = (CELL)ptd0; /* next make sure noone will see this as a variable again */ if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) { /* Trail overflow */ if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) { goto trail_overflow; } } TrailTerm(TR++) = (CELL)ptd0; END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } clean_tr(TR0 PASS_REGS); pop_text_stack(lvl); if (HR != InitialH) { /* close the list */ Term t2 = Deref(inp); if (IsVarTerm(t2)) { RESET_VARIABLE(HR - 1); Yap_unify((CELL)(HR - 1), inp); } else { HR[-1] = t2; /* don't need to trail */ } return (output); } else { return (inp); } def_trail_overflow(); def_aux_overflow(); def_global_overflow(); } /** * @pred variables_in_term( +_T_, +_SetOfVariables_, +_ExtendedSetOfVariables_ ) * * _SetOfVariables_ must be a list of unbound variables. If so, * _ExtendedSetOfVariables_ will include all te variables in the union * of `vars(_T_)` and _SetOfVariables_. */ static Int variables_in_term(USES_REGS1) /* variables in term t */ { Term out, inp; int count; restart: count = 0; inp = Deref(ARG2); while (!IsVarTerm(inp) && IsPairTerm(inp)) { Term t = HeadOfTerm(inp); if (IsVarTerm(t)) { CELL *ptr = VarOfTerm(t); *ptr = TermFoundVar; TrailTerm(TR++) = t; count++; if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) { clean_tr(TR - count PASS_REGS); if (!Yap_growtrail(count * sizeof(tr_fr_ptr *), false)) { return false; } goto restart; } } inp = TailOfTerm(inp); } do { Term t = Deref(ARG1); out = vars_in_complex_term(&(t)-1, &(t), ARG2 PASS_REGS); if (out == 0L) { if (!expand_vts(3 PASS_REGS)) return false; } } while (out == 0L); clean_tr(TR - count PASS_REGS); return Yap_unify(ARG3, out); } /** @pred term_variables(? _Term_, - _Variables_, +_ExternalVars_) is iso Unify the difference list between _Variables_ and _ExternaVars_ with the list of all variables of term _Term_. The variables occur in the order of their first appearance when traversing the term depth-first, left-to-right. */ static Int p_term_variables3(USES_REGS1) /* variables in term t */ { Term out; do { Term t = Deref(ARG1); if (IsVarTerm(t)) { Term out = Yap_MkNewPairTerm(); return Yap_unify(t, HeadOfTerm(out)) && Yap_unify(ARG3, TailOfTerm(out)) && Yap_unify(out, ARG2); } else if (IsPrimitiveTerm(t)) { return Yap_unify(ARG2, ARG3); } else { out = vars_in_complex_term(&(t)-1, &(t), ARG3 PASS_REGS); } if (out == 0L) { if (!expand_vts(3 PASS_REGS)) return false; } } while (out == 0L); return Yap_unify(ARG2, out); } /** * Exports a nil-terminated list with all the variables in a term. * @param[t] the term * @param[arity] the arity of the calling predicate (required for exact garbage * collection). * @param[USES_REGS] threading */ Term Yap_TermVariables( Term t, UInt arity USES_REGS) /* variables in term t */ { Term out; do { t = Deref(t); if (IsVarTerm(t)) { return MkPairTerm(t, TermNil); } else if (IsPrimitiveTerm(t)) { return TermNil; } else { out = vars_in_complex_term(&(t)-1, &(t), TermNil PASS_REGS); } if (out == 0L) { if (!expand_vts(arity PASS_REGS)) return false; } } while (out == 0L); return out; } /** @pred term_variables(? _Term_, - _Variables_) is iso Unify _Variables_ with the list of all variables of term _Term_. The variables occur in the order of their first appearance when traversing the term depth-first, left-to-right. */ static Int p_term_variables(USES_REGS1) /* variables in term t */ { Term out; if (!Yap_IsListOrPartialListTerm(ARG2)) { Yap_Error(TYPE_ERROR_LIST, ARG2, "term_variables/2"); return false; } do { Term t = Deref(ARG1); out = vars_in_complex_term(&(t)-1, &(t), TermNil PASS_REGS); if (out == 0L) { if (!expand_vts(3 PASS_REGS)) return false; } } while (out == 0L); return Yap_unify(ARG2, out); } /** routine to locate attributed variables */ typedef struct att_rec { CELL *beg, *end; CELL oval; } att_rec_t; static Term attvars_in_complex_term(register CELL *pt0, register CELL *pt0_end, Term inp USES_REGS) { register tr_fr_ptr TR0 = TR; CELL *InitialH = HR; CELL output = inp; WALK_COMPLEX_TERM(); if (IsAttVar(ptd0)) { /* do or pt2 are unbound */ attvar_record *a0 = RepAttVar(ptd0); if (a0->AttFunc == (Functor)TermNil) goto restart; /* leave an empty slot to fill in later */ if (HR + 1024 > ASP) { goto global_overflow; } output = MkPairTerm( (CELL) & (a0->Done), output); /* store the terms to visit */ if (to_visit + 32 >= to_visit_max) { goto aux_overflow; } ptd0 = (CELL *)a0; to_visit->pt0 = pt0; to_visit->pt0_end = pt0_end; to_visit->d0 = *ptd0; to_visit->ptd0 = ptd0; to_visit++; *ptd0 = TermNil; pt0_end = &RepAttVar(ptd0)->Atts; pt0 = pt0_end - 1; } END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } clean_tr(TR0 PASS_REGS); pop_text_stack(lvl); if (HR != InitialH) { /* close the list */ Term t2 = Deref(inp); if (IsVarTerm(t2)) { RESET_VARIABLE(HR - 1); Yap_unify((CELL)(HR - 1), t2); } else { HR[-1] = t2; /* don't need to trail */ } } return (output); def_aux_overflow(); def_global_overflow(); } /** @pred term_attvars(+ _Term_,- _AttVars_) _AttVars_ is a list of all attributed variables in _Term_ and its attributes. I.e., term_attvars/2 works recursively through attributes. This predicate is Cycle-safe. */ static Int p_term_attvars(USES_REGS1) /* variables in term t */ { Term out; do { Term t = Deref(ARG1); if (IsPrimitiveTerm(t)) { return Yap_unify(TermNil, ARG2); } else { out = attvars_in_complex_term(&(t)-1, &(t), TermNil PASS_REGS); } if (out == 0L) { if (!expand_vts(3 PASS_REGS)) return false; } } while (out == 0L); return Yap_unify(ARG2, out); } /** @brief output the difference between variables in _T_ and variables in some * list. */ static Term new_vars_in_complex_term(register CELL *pt0, register CELL *pt0_end, Term inp USES_REGS) { register tr_fr_ptr TR0 = TR; CELL *InitialH = HR; CELL output = AbsPair(HR); { int lvl = push_text_stack(); while (!IsVarTerm(inp) && IsPairTerm(inp)) { Term t = HeadOfTerm(inp); if (IsVarTerm(t)) { CELL *ptr = VarOfTerm(t); *ptr = TermFoundVar; TrailTerm(TR++) = t; if ((tr_fr_ptr)LOCAL_TrailTop - TR < 1024) { if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) { goto trail_overflow; } } } inp = TailOfTerm(inp); } pop_text_stack(lvl); } WALK_COMPLEX_TERM(); /* do or pt2 are unbound */ *ptd0 = TermNil; /* leave an empty slot to fill in later */ if (HR + 1024 > ASP) { goto global_overflow; } HR[1] = AbsPair(HR + 2); HR += 2; HR[-2] = (CELL)ptd0; /* next make sure noone will see this as a variable again */ if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) { /* Trail overflow */ while (to_visit > to_visit0) { to_visit--; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; } if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) { goto trail_overflow; } } TrailTerm(TR++) = (CELL)ptd0; END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } clean_tr(TR0 PASS_REGS); pop_text_stack(lvl); if (HR != InitialH) { HR[-1] = TermNil; return output; } else { return 0; } def_aux_overflow(); def_trail_overflow(); def_global_overflow(); } /** @pred new_variables_in_term(+_CurrentVariables_, ? _Term_, -_Variables_) Unify _Variables_ with the list of all variables of term _Term_ that do not occur in _CurrentVariables_. The variables occur in the order of their first appearance when traversing the term depth-first, left-to-right. */ static Int p_new_variables_in_term(USES_REGS1) /* variables within term t */ { Term out; do { Term t = Deref(ARG2); if (IsPrimitiveTerm(t)) out = TermNil; else { out = new_vars_in_complex_term(&(t)-1, &(t), Deref(ARG1) PASS_REGS); } if (out == 0L) { if (!expand_vts(3 PASS_REGS)) return false; } } while (out == 0L); return Yap_unify(ARG3, out); } #define FOUND_VAR() \ if (d0 == TermFoundVar) { \ /* leave an empty slot to fill in later */ \ if (HR + 1024 > ASP) { \ goto global_overflow; \ } \ HR[1] = AbsPair(HR + 2); \ HR += 2; \ HR[-2] = (CELL)ptd0; \ *ptd0 = TermNil; \ } static Term vars_within_complex_term(register CELL *pt0, register CELL *pt0_end, Term inp USES_REGS) { tr_fr_ptr TR0 = TR; CELL *InitialH = HR; CELL output = AbsPair(HR); while (!IsVarTerm(inp) && IsPairTerm(inp)) { Term t = HeadOfTerm(inp); if (IsVarTerm(t)) { CELL *ptr = VarOfTerm(t); *ptr = TermFoundVar; TrailTerm(TR++) = t; if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) { Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true); } } inp = TailOfTerm(inp); } WALK_COMPLEX_TERM__({}, {}, FOUND_VAR()); END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } clean_tr(TR0 PASS_REGS); pop_text_stack(lvl); if (HR != InitialH) { HR[-1] = TermNil; return output; } else { return TermNil; } def_aux_overflow(); def_global_overflow(); } /** @pred variables_within_term(+_CurrentVariables_, ? _Term_, -_Variables_) Unify _Variables_ with the list of all variables of term _Term_ that *also* occur in _CurrentVariables_. The variables occur in the order of their first appearance when traversing the term depth-first, left-to-right. This predicate performs the opposite of new_variables_in_term/3. */ static Int p_variables_within_term(USES_REGS1) /* variables within term t */ { Term out; do { Term t = Deref(ARG2); if (IsPrimitiveTerm(t)) out = TermNil; else { out = vars_within_complex_term(&(t)-1, &(t), Deref(ARG1) PASS_REGS); } if (out == 0L) { if (!expand_vts(3 PASS_REGS)) return false; } } while (out == 0L); return Yap_unify(ARG3, out); } static Term free_vars_in_complex_term(CELL *pt0, CELL *pt0_end, tr_fr_ptr TR0 USES_REGS) { Term o = TermNil; CELL *InitialH = HR; WALK_COMPLEX_TERM(); /* do or pt2 are unbound */ *ptd0 = TermNil; /* leave an empty slot to fill in later */ if (HR + 1024 > ASP) { o = TermNil; goto global_overflow; } HR[0] = (CELL)ptd0; HR[1] = o; o = AbsPair(HR); HR += 2; /* next make sure noone will see this as a variable again */ if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) { /* Trail overflow */ if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) { goto trail_overflow; } } TrailTerm(TR++) = (CELL)ptd0; END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } clean_tr(TR0 PASS_REGS); pop_text_stack(lvl); return o; def_aux_overflow(); def_trail_overflow(); def_global_overflow(); } static Term bind_vars_in_complex_term(CELL *pt0, CELL *pt0_end, tr_fr_ptr TR0 USES_REGS) { CELL *InitialH = HR; WALK_COMPLEX_TERM(); /* do or pt2 are unbound */ *ptd0 = TermFoundVar; /* next make sure noone will see this as a variable again */ if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) { /* Trail overflow */ if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) { while (to_visit > to_visit0) { to_visit--; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; } goto trail_overflow; } } TrailTerm(TR++) = (CELL)ptd0; END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->ptd0; *pt0 = to_visit0->d0; goto list_loop; } pop_text_stack(lvl); return TermNil; def_aux_overflow(); def_trail_overflow(); } static Int p_free_variables_in_term(USES_REGS1) /* variables within term t */ { Term out; Term t, t0; Term found_module = 0L; do { tr_fr_ptr TR0 = TR; t = t0 = Deref(ARG1); while (!IsVarTerm(t) && IsApplTerm(t)) { Functor f = FunctorOfTerm(t); if (f == FunctorHat) { out = bind_vars_in_complex_term(RepAppl(t), RepAppl(t) + 1, TR0 PASS_REGS); if (out == 0L) { goto trail_overflow; } } else if (f == FunctorModule) { found_module = ArgOfTerm(1, t); } else if (f == FunctorCall) { t = ArgOfTerm(1, t); } else if (f == FunctorExecuteInMod) { found_module = ArgOfTerm(2, t); t = ArgOfTerm(1, t); } else { break; } t = ArgOfTerm(2, t); } if (IsPrimitiveTerm(t)) out = TermNil; else { out = free_vars_in_complex_term(&(t)-1, &(t), TR0 PASS_REGS); } if (out == 0L) { trail_overflow: if (!expand_vts(3 PASS_REGS)) return false; } } while (out == 0L); if (found_module && t != t0) { Term ts[2]; ts[0] = found_module; ts[1] = t; t = Yap_MkApplTerm(FunctorModule, 2, ts); } return Yap_unify(ARG2, t) && Yap_unify(ARG3, out); } #define FOUND_VAR_AGAIN() \ if (d0 == TermFoundVar) { \ CELL *pt2 = pt0; \ while (IsVarTerm(*pt2)) \ pt2 = (CELL *)(*pt2); \ HR[1] = AbsPair(HR + 2); \ HR[0] = (CELL)pt2; \ HR += 2; \ *pt2 = TermRefoundVar; \ } static Term non_singletons_in_complex_term(CELL *pt0, CELL *pt0_end USES_REGS) { tr_fr_ptr TR0 = TR; CELL *InitialH = HR; HB = (CELL *)ASP; CELL output = AbsPair(HR); WALK_COMPLEX_TERM__({}, {}, FOUND_VAR_AGAIN()); /* do or pt2 are unbound */ YapBind(ptd0,TermFoundVar); END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } clean_tr(TR0 PASS_REGS); pop_text_stack(lvl); HB = (CELL*)B->cp_b; if (HR != InitialH) { /* close the list */ HR[-1] = Deref(ARG2); return output; } else { return ARG2; } def_aux_overflow(); } static Int p_non_singletons_in_term( USES_REGS1) /* non_singletons in term t */ { Term t; Term out; while (true) { t = Deref(ARG1); if (IsVarTerm(t)) { out = ARG2; } else if (IsPrimitiveTerm(t)) { out = ARG2; } else { out = non_singletons_in_complex_term(&(t)-1, &(t)PASS_REGS); } if (out != 0L) { return Yap_unify(ARG3, out); } } } static Term numbervar(Int id USES_REGS) { Term ts[1]; ts[0] = MkIntegerTerm(id); return Yap_MkApplTerm(FunctorDollarVar, 1, ts); } static Term numbervar_singleton(USES_REGS1) { Term ts[1]; ts[0] = MkIntegerTerm(-1); return Yap_MkApplTerm(FunctorDollarVar, 1, ts); } static void renumbervar(Term t, Int id USES_REGS) { Term *ts = RepAppl(t); ts[1] = MkIntegerTerm(id); } #define RENUMBER_SINGLES \ if (singles ) { \ renumbervar(d0, numbv++ PASS_REGS); \ goto restart; \ } static Int numbervars_in_complex_term(CELL *pt0, CELL *pt0_end, Int numbv, int singles USES_REGS) { tr_fr_ptr TR0 = TR; CELL *InitialH = HR; WALK_COMPLEX_TERM__({}, RENUMBER_SINGLES, {}); if (IsAttVar(pt0)) continue; /* do or pt2 are unbound */ if (singles) d0 = numbervar_singleton(PASS_REGS1); else d0 = numbervar(numbv++ PASS_REGS); /* leave an empty slot to fill in later */ if (HR + 1024 > ASP) { goto global_overflow; } /* next make sure noone will see this as a variable again */ YapBind(ptd0, d0); continue; END_WALK(); /* Do we still have compound terms to visit */ while (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; if (pt0 >= pt0_end) continue; goto restart; } pop_text_stack(lvl); return numbv; def_aux_overflow(); def_global_overflow(); def_trail_overflow(); } Int Yap_NumberVars(Term inp, Int numbv, bool handle_singles) /* * numbervariables in term t */ { CACHE_REGS Int out; Term t; restart: t = Deref(inp); if (IsPrimitiveTerm(t)) { return numbv; } else { out = numbervars_in_complex_term(&(t)-1, &(t), numbv, handle_singles PASS_REGS); } if (out < numbv) { if (!expand_vts(3 PASS_REGS)) return false; goto restart; } return out; } /** @pred numbervars( _T_,+ _N1_,- _Nn_) Instantiates each variable in term _T_ to a term of the form: `$VAR( _I_)`, with _I_ increasing from _N1_ to _Nn_. */ static Int p_numbervars(USES_REGS1) { Term t2 = Deref(ARG2); Int out; if (IsVarTerm(t2)) { Yap_Error(INSTANTIATION_ERROR, t2, "numbervars/3"); return false; } if (!IsIntegerTerm(t2)) { Yap_Error(TYPE_ERROR_INTEGER, t2, "numbervars/3"); return (false); } if ((out = Yap_NumberVars(ARG1, IntegerOfTerm(t2), false)) < 0) return false; return Yap_unify(ARG3, MkIntegerTerm(out)); } #define MAX_NUMBERED \ if (FunctorOfTerm(d0) == FunctorDollarVar) { \ Term t1 = ArgOfTerm(1, d0); \ Int i; \ if (IsIntegerTerm(t1) && ((i = IntegerOfTerm(t1)) > *maxp)) \ *maxp = i; \ goto restart; \ } static int max_numbered_var(CELL *pt0, CELL *pt0_end, Int *maxp USES_REGS) { WALK_COMPLEX_TERM__({}, MAX_NUMBERED, {}); END_WALK(); /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; pt0_end = to_visit->pt0_end; CELL *ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; } prune(B PASS_REGS); pop_text_stack(lvl); return 0; def_aux_overflow(); } static Int MaxNumberedVar(Term inp, UInt arity PASS_REGS) { Term t = Deref(inp); if (IsPrimitiveTerm(t)) { return MkIntegerTerm(0); } else { Int res; Int max; res = max_numbered_var(&t - 1, &t, &max PASS_REGS) - 1; if (res < 0) return -1; return MkIntegerTerm(max); } } /** * @pred largest_numbervar( +_Term_, -Max) * * Unify _Max_ with the largest integer _I_ such that `$VAR(I)` is a * sub-term of _Term_. * * This built-in predicate is useful if part of a term has been grounded, and * now you want to ground the full term. */ static Int largest_numbervar(USES_REGS1) { return Yap_unify(MaxNumberedVar(Deref(ARG1), 2 PASS_REGS), ARG2); } static Term BREAK_LOOP(int ddep) { Term t0 = MkIntegerTerm(ddep); return Yap_MkApplTerm(Yap_MkFunctor(Yap_LookupAtom("@^"), 1), 1, &t0); } static Term UNFOLD_LOOP(Term t, Term *b) { Term os[2], o; os[0] = o = MkVarTerm(); os[1] = t; Term ti = Yap_MkApplTerm(FunctorEq, 2, os); *b = MkPairTerm(ti, *b); return o; } static int loops_in_complex_term(CELL *pt0, CELL *pt0_end, Term *listp, Term tail USES_REGS) { int lvl = push_text_stack(); struct non_single_struct_t *to_visit = Malloc( 1024 * sizeof(struct non_single_struct_t)), *to_visit0 = to_visit, *to_visit_max = to_visit + 1024; CELL *ptf = HR; CELL *ptd0; if (listp) *listp = tail; restart: while (pt0 < pt0_end) { CELL d0; ++pt0; ptd0 = pt0; d0 = *ptd0; list_loop: deref_head(d0, vars_in_term_unk); vars_in_term_nvar: if (IsPairTerm(d0)) { if (to_visit + 32 >= to_visit_max) { goto aux_overflow; } CELL *ptd0 = RepPair(d0); d0 = ptd0[0]; if (IsAtomTerm(d0) && (CELL *)AtomOfTerm(d0) >= (CELL *)to_visit0 && (CELL *)AtomOfTerm(d0) < (CELL *)to_visit) { // LIST0; struct non_single_struct_t *v0 = (struct non_single_struct_t *)AtomOfTerm(d0); if (listp) { *ptf = UNFOLD_LOOP(AbsPair(v0->ptf-1), listp); ptf++; } else { *ptf++ = BREAK_LOOP(to_visit - v0); } continue; } *ptf++ = AbsPair(HR); to_visit->pt0 = pt0; to_visit->pt0_end = pt0_end; to_visit->ptd0 = ptd0; to_visit->ptf = ptf; to_visit->d0 = d0 = *ptd0; *ptd0 = MkAtomTerm((AtomEntry *)to_visit); to_visit++; pt0 = ptd0; pt0_end = pt0 + 1; ptd0 = pt0; ptf = HR; HR+=2; goto list_loop; } else if (IsApplTerm(d0)) { register Functor f; /* store the terms to visit */ ptd0 = RepAppl(d0); f = (Functor)(*ptd0); if (IsExtensionFunctor(f)) { *ptf++ = d0; continue; } if (IsAtomTerm((CELL)f)) { struct non_single_struct_t *v0 = (struct non_single_struct_t *)AtomOfTerm(*ptd0); if (listp) { *ptf = UNFOLD_LOOP(AbsAppl(v0->ptf-1), listp); ptf++; } else { *ptf++ = BREAK_LOOP(to_visit - v0); } continue; } // STRUCT0; if (to_visit + 32 >= to_visit_max) { goto aux_overflow; } *ptf++ = AbsAppl(HR); to_visit->pt0 = pt0; to_visit->pt0_end = pt0_end; to_visit->ptd0 = ptd0; to_visit->d0 = *ptd0; to_visit->ptf = ptf; *ptd0 = MkAtomTerm((AtomEntry *)to_visit); to_visit++; pt0 = ptd0; pt0_end = ptd0 + (ArityOfFunctor(f)); HR[0] = (CELL)f; ptf = HR+1; HR = ptf +ArityOfFunctor(f); } else { *ptf++ = d0; } goto restart; derefa_body(d0, ptd0, vars_in_term_unk, vars_in_term_nvar); *ptf++ = d0; goto restart; } /* Do we still have compound terms to visit */ if (to_visit > to_visit0) { to_visit--; pt0 = to_visit->pt0; ptf = to_visit->ptf; pt0_end = to_visit->pt0_end; ptd0 = to_visit->ptd0; *ptd0 = to_visit->d0; goto restart; } pop_text_stack(lvl); return 0; def_aux_overflow(); } Term Yap_BreakCycles(Term inp, UInt arity, Term *listp, Term tail USES_REGS) { Term t = Deref(inp); if (IsVarTerm(t) || IsPrimitiveTerm(t)) { return t; } else { Int res; CELL *op = HR; res = loops_in_complex_term((&t) - 1, &t, listp, tail PASS_REGS); if (res < 0) return -1; if (IsPairTerm(t)) return AbsPair(op); else return AbsAppl(op); } } /** @pred rational_term_to_tree(? _TI_,- _TF_, ?SubTerms, ?MoreSubterms) The term _TF_ is a forest representation (without cycles) for the Prolog term _TI_. The term _TF_ is the main term. The difference list _SubTerms_-_MoreSubterms_ stores terms of the form _V=T_, where _V_ is a new variable occuring in _TF_, and _T_ is a copy of a sub-term from _TI_. */ static Int p_break_rational(USES_REGS1) { Term t = (ARG1); Term l = Deref(ARG4), k; if (IsVarTerm(l)) Yap_unify(l, MkVarTerm()); return Yap_unify(Yap_BreakCycles(t, 4, &k, l PASS_REGS), ARG2) && Yap_unify(k, ARG3); } void Yap_InitTermCPreds(void) { Yap_InitCPred("rational_term_to_tree", 4, p_break_rational, 0); Yap_InitCPred("term_variables", 2, p_term_variables, 0); Yap_InitCPred("term_variables", 3, p_term_variables3, 0); Yap_InitCPred("$variables_in_term", 3, variables_in_term, 0); Yap_InitCPred("$free_variables_in_term", 3, p_free_variables_in_term, 0); Yap_InitCPred("term_attvars", 2, p_term_attvars, 0); CurrentModule = TERMS_MODULE; Yap_InitCPred("variable_in_term", 2, variable_in_term, 0); Yap_InitCPred("variables_within_term", 3, p_variables_within_term, 0); Yap_InitCPred("new_variables_in_term", 3, p_new_variables_in_term, 0); CurrentModule = PROLOG_MODULE; Yap_InitCPred("$non_singletons_in_term", 3, p_non_singletons_in_term, 0); Yap_InitCPred("ground", 1, ground, SafePredFlag); Yap_InitCPred("cyclic_term", 1, cyclic_term, SafePredFlag); Yap_InitCPred("numbervars", 3, p_numbervars, 0); Yap_InitCPred("largest_numbervar", 2, largest_numbervar, 0); }