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9156b90b66
yap-6.3/C/terms.c
Vitor Santos Costa 044329d115 bbdd
2019-03-15 12:38:09 +00:00

1416 lines
33 KiB
C
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/*************************************************************************
* *
* 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"
#define debug_pop_text_stack(l) [ if (to_visit != to_visit0) printf("%d\n",__LINE__); pop_text_stack(l) \
}
#include "attvar.h"
#include "yapio.h"
#ifdef HAVE_STRING_H
#include "string.h"
#endif
extern int cs[10];
int cs[10];
static inline void clean_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;
}
//#define CELL *pt0, *pt0_end, *ptf;
//} non_singletons_t;
#define IS_VISIT_MARKER \
(IsAtomTerm(d0) && AtomOfTerm(d0) >= (Atom)to_visit0 && \
AtomOfTerm(d0) <= (Atom)to_visit)
#define VISIT_MARKER MkAtomTerm((Atom)to_visit)
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();\
CELL *pt0, *pt0_end; \
size_t auxsz = 1024 * sizeof(struct non_single_struct_t);\
struct non_single_struct_t *to_visit0=NULL, *to_visit,* to_visit_max;\
CELL *InitialH = HR;\
tr_fr_ptr TR0 = TR;\
if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) { \
/* Trail overflow */\
goto trail_overflow;\
}\
if (HR + 1024 > ASP) { \
goto global_overflow;\
}\
reset:\
to_visit0 = Realloc(to_visit0,auxsz); \
pt0 = pt0_; pt0_end = pt0_end_; \
to_visit = to_visit0, \
to_visit_max = to_visit + auxsz/sizeof(struct non_single_struct_t);\
\
while (to_visit >= to_visit0) { \
CELL d0; \
CELL *ptd0; \
restart: \
while (pt0 < pt0_end) { \
++pt0; \
ptd0 = pt0; \
d0 = *ptd0; \
list_loop: \
/*fprintf(stderr, "%ld at %s\n", to_visit - to_visit0, __FUNCTION__);*/ \
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); \
d0 = ptd0[0]; \
LIST0; \
if (IS_VISIT_MARKER) \
goto restart; \
to_visit->pt0 = pt0; \
to_visit->pt0_end = pt0_end; \
to_visit->ptd0 = ptd0; \
to_visit->d0 = d0; \
to_visit++; \
*ptd0 = VISIT_MARKER; \
pt0 = ptd0; \
pt0_end = pt0 + 1; \
goto list_loop; \
} else if (IsApplTerm(d0)) { \
register Functor f; \
/* store the terms to visit */ \
ptd0 = RepAppl(d0); \
f = (Functor)(d0 = *ptd0); \
if (IsExtensionFunctor(f)) {\
continue;\
}\
\
if (to_visit + 32 >= to_visit_max) { \
goto aux_overflow; \
} \
STRUCT0; \
if (IS_VISIT_MARKER) { \
\
continue; \
} \
to_visit->pt0 = pt0; \
to_visit->pt0_end = pt0_end; \
to_visit->ptd0 = ptd0; \
to_visit->d0 = d0; \
to_visit++; \
\
*ptd0 = VISIT_MARKER; \
Term d1 = ArityOfFunctor(f); \
pt0 = ptd0; \
pt0_end = ptd0 + d1; \
continue; \
} else { \
if (IS_VISIT_MARKER) { \
\
continue; \
} \
PRIMI0; \
continue; \
} \
derefa_body(d0, ptd0, var_in_term_unk, var_in_term_nvar)
#define WALK_COMPLEX_TERM() WALK_COMPLEX_TERM__({}, {}, {})
#define END_WALK() \
} \
} \
/* Do we still have compound terms to visit */ \
to_visit--; \
if (to_visit >= to_visit0) { \
pt0 = to_visit->pt0; \
pt0_end = to_visit->pt0_end; \
*to_visit->ptd0 = to_visit->d0; \
} \
} \
pop_text_stack(lvl);
#define def_aux_overflow() \
aux_overflow : { \
while (to_visit > to_visit0) { \
to_visit--; \
CELL *ptd0 = to_visit->ptd0; \
*ptd0 = to_visit->d0; \
} \
clean_tr(TR0 PASS_REGS); \
auxsz += auxsz;\
goto reset; }
#define def_trail_overflow() \
trail_overflow: { \
while (to_visit > to_visit0) { \
to_visit--; \
CELL *ptd0 = to_visit->ptd0; \
*ptd0 = to_visit->d0; \
} \
size_t expand = (TR - TR0) * sizeof(tr_fr_ptr *); \
clean_tr(TR0 PASS_REGS); \
HR = InitialH; \
pop_text_stack(lvl); \
/* Trail overflow */ \
if (!Yap_growtrail(expand, false)) { \
Yap_ThrowError(RESOURCE_ERROR_TRAIL, TermNil, expand);\
} \
goto reset;\
}
#define def_global_overflow() \
global_overflow : { \
while (to_visit > to_visit0) { \
to_visit--; \
CELL *ptd0 = to_visit->ptd0; \
*ptd0 = to_visit->d0; \
} \
clean_tr(TR0 PASS_REGS); \
HR = InitialH; \
LOCAL_Error_TYPE = RESOURCE_ERROR_STACK; \
size_t expand = 0L; \
if (!Yap_gcl(expand, 3, ENV, gc_P(P, CP))) { \
Yap_ThrowError(RESOURCE_ERROR_STACK, TermNil, sizeof(CELL)*(HR-H0)); \
return false;\
}\
goto reset;\
}
#define CYC_LIST \
if (IS_VISIT_MARKER) { \
while (to_visit > to_visit0) { \
to_visit--; \
to_visit->ptd0[0] = to_visit->d0; \
} \
pop_text_stack(lvl); \
return true; \
}
#define def_overflow() \
def_aux_overflow(); \
def_global_overflow(); \
def_trail_overflow()
#define CYC_APPL \
if (IS_VISIT_MARKER) { \
while (to_visit > to_visit0) { \
to_visit--; \
to_visit->ptd0[0] = 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(CELL *pt0_, CELL *pt0_end_ USES_REGS) {
WALK_COMPLEX_TERM__(CYC_LIST, CYC_APPL, {});
/* leave an empty slot to fill in later */
END_WALK();
return false;
def_overflow();
}
bool Yap_IsCyclicTerm(Term t USES_REGS) {
cs[2]++;
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));
}
static Term BREAK_LOOP(CELL d0,struct non_single_struct_t *to_visit ) {
char buf[64];
snprintf(buf, 63, "@^[" Int_FORMAT "]", to_visit-(struct non_single_struct_t*)AtomOfTerm(d0));
return MkAtomTerm(Yap_LookupAtom(buf));
}
/**
@brief routine to locate all variables in a term, and its applications */
static int cycles_in_complex_term( CELL *pt0_, CELL *pt0_end_ USES_REGS) {
CELL *pt0, *pt0_end;
int lvl = push_text_stack();
size_t auxsz = 1024 * sizeof(struct non_single_struct_t);
struct non_single_struct_t *to_visit0=NULL, *to_visit, *to_visit_max;
CELL *InitialH = HR;
tr_fr_ptr TR0 = TR;
if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) { \
/* Trail overflow */\
goto trail_overflow;\
}\
reset:
pt0 = pt0_, pt0_end = pt0_end_;
to_visit0 = Realloc(to_visit0,auxsz);
to_visit= to_visit0;
to_visit_max = to_visit0 + auxsz/sizeof(struct non_single_struct_t);
auxsz *= 2;
int rc = 0;
CELL *ptf;
ptf = HR;
HR++;
while (to_visit >= to_visit0) {
CELL d0;
CELL *ptd0;
while (pt0 < pt0_end) {
++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);
d0 = ptd0[0];
if (IS_VISIT_MARKER) {
rc++;
*ptf++ = BREAK_LOOP(d0, to_visit);
continue;
}
*ptf++ = AbsPair(HR);
to_visit->pt0 = pt0;
to_visit->pt0_end = pt0_end;
to_visit->ptd0 = ptd0;
to_visit->d0 = d0;
to_visit->ptf = ptf;
to_visit++;
ptf = HR;
if (HR + 1024 > ASP) { \
goto global_overflow;\
}\
HR += 2;
*ptd0 = VISIT_MARKER;
pt0 = ptd0;
pt0_end = pt0+1;
ptf = HR - 2;
goto list_loop;
} else if (IsApplTerm(d0)) {
register Functor f;
/* store the terms to visit */
ptd0 = RepAppl(d0);
f = (Functor)(d0 = *ptd0);
if (IsExtensionFunctor(f)) {
*ptf++ = AbsAppl(ptd0);
continue;
}
if (IS_VISIT_MARKER) {
rc++;
*ptf++ = BREAK_LOOP(d0, to_visit);
continue;
}
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 = d0;
to_visit->ptf = ptf;
to_visit++;
*ptd0 = VISIT_MARKER;
*HR++ = (CELL)f;
ptf = HR;
Term d1 = ArityOfFunctor(f);
pt0 = ptd0;
pt0_end = ptd0 + (d1);
HR+=d1;
continue;
} else {
if (IS_VISIT_MARKER) {
rc++;
*ptf++ = BREAK_LOOP(d0, to_visit);
continue;
}
*ptf++ = d0;
continue;
}
derefa_body(d0, ptd0, var_in_term_unk, var_in_term_nvar);
*ptf++ = d0;
}
}
/* Do we still have compound terms to visit */
to_visit--;
if (to_visit >= to_visit0) {
pt0 = to_visit->pt0;
pt0_end = to_visit->pt0_end;
ptf = to_visit->ptf;
*to_visit->ptd0 = to_visit->d0;
}
}
pop_text_stack(lvl);
return rc;
def_overflow();
}
Term Yap_CyclesInTerm(Term t USES_REGS) {
cs[3]++;
t = Deref(t);
if (IsVarTerm(t)) {
return t;
} else if (IsPrimitiveTerm(t)) {
return t;
} else {
CELL *Hi = HR;
if ( cycles_in_complex_term(&(t)-1, &(t)PASS_REGS) >0) {
return Hi[0];
} else {
HR = Hi;
return t;
}
}
}
/** @pred cycles_in_term( + _T_ )
Succeeds if the graph representation of the term has markers in every
loop. 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 cycles_in_term(USES_REGS1) /* cyclic_term(+T) */
{
return Yap_CyclesInTerm(Deref(ARG1));
}
/**
@brief routine to locate all variables in a term, and its applications */
static bool ground_complex_term(CELL * pt0_, 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 */
pop_text_stack(lvl);
return true;
def_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(CELL *pt0_, CELL *pt0_end_ ,
Term v USES_REGS) {
WALK_COMPLEX_TERM();
if ((CELL)ptd0 == 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;
}
goto restart;
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_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(CELL *pt0_, CELL *pt0_end_ ,
Term inp USES_REGS) {
Int count=0;
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;
}
}
}
inp = TailOfTerm(inp);
}
CELL output = AbsPair(HR);
WALK_COMPLEX_TERM();
/* do or pt2 are unbound */
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 */
goto trail_overflow;
}
TrailTerm(TR++) = (CELL)ptd0;
*ptd0 = TermFoundVar;
END_WALK();
clean_tr(TR0-count 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);
} else {
return (inp);
}
def_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;
inp = Deref(ARG2);
Term t = Deref(ARG1);
out = vars_in_complex_term(&(t)-1, &(t), inp 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 term_variables3(
USES_REGS1) /* variables in term t */
{
Term out;
cs[0]++;
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);
}
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;
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);
}
return out;
}
static Term Yap_TermAddVariables(
Term t, Term vs USES_REGS) /* variables in term t */
{
Term out;
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), vs PASS_REGS);
}
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 term_variables(
USES_REGS1) /* variables in term t */
{
Term out;
if (!Yap_IsListOrPartialListTerm(ARG2)) {
Yap_ThrowError(TYPE_ERROR_LIST, ARG2, "term_variables/2");
return false;
}
Term t = Deref(ARG1);
out = vars_in_complex_term(&(t)-1, &(t), TermNil PASS_REGS);
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(
CELL *pt0_, CELL *pt0_end_ , Term inp USES_REGS) {
CELL output = inp;
WALK_COMPLEX_TERM();
if (IsAttVar(ptd0)) {
/* do or pt2 are unbound */
attvar_record *a0 = RepAttVar(ptd0);
d0 = *ptd0;
/* 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;
}
TrailTerm(TR++) = a0->Done;
a0->Done=TermNil;
if ((tr_fr_ptr)LOCAL_TrailTop - TR < 1024) {
if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) {
goto trail_overflow;
}
pop_text_stack(lvl);
}
pt0_end = &a0->Atts;
pt0 = pt0_end - 1;
}
END_WALK();
clean_tr(TR0 PASS_REGS);
pop_text_stack(lvl);
/*fprintf(stderr,"<%ld at %s\n", d0, __FUNCTION__)*/;
return output;
def_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 term_attvars(USES_REGS1) /* variables in term t */
{
Term out;
Term t = Deref(ARG1);
if (IsPrimitiveTerm(t)) {
return Yap_unify(TermNil, ARG2);
} else {
out = attvars_in_complex_term(&(t)-1, &(t), TermNil PASS_REGS);
}
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(
CELL *pt0_, CELL *pt0_end_ , Term inp USES_REGS) {
Int n=0;
CELL output = TermNil;
{
int lvl = push_text_stack();
while (!IsVarTerm(inp) && IsPairTerm(inp)) {
Term t = HeadOfTerm(inp);
if (IsVarTerm(t)) {
n++;
TrailTerm(TR++) = t;
*VarOfTerm(t) = TermFoundVar;
if ((tr_fr_ptr)LOCAL_TrailTop - TR < 1024) {
if (!Yap_growtrail(n * sizeof(tr_fr_ptr *), true)) {
goto trail_overflow;
}
}
}
inp = TailOfTerm(inp);
}
pop_text_stack(lvl);
}
WALK_COMPLEX_TERM();
output = MkPairTerm((CELL)ptd0, output);
TrailTerm(TR++) = *ptd0;
*ptd0 = TermFoundVar;
if ((tr_fr_ptr)LOCAL_TrailTop - TR < 1024) {
goto trail_overflow;
}
/* leave an empty slot to fill in later */
if (HR + 1024 > ASP) {
goto global_overflow;
}
END_WALK();
clean_tr(TR0-n PASS_REGS);
pop_text_stack(lvl);
return output;
def_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;
Term t = Deref(ARG2);
if (IsPrimitiveTerm(t))
out = TermNil;
else {
out = new_vars_in_complex_term(&(t)-1, &(t), Deref(ARG1) PASS_REGS);
}
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(
CELL *pt0_, CELL *pt0_end_, Term inp USES_REGS) {
Int n=0;
CELL output = AbsPair(HR);
while (!IsVarTerm(inp) && IsPairTerm(inp)) {
Term t = HeadOfTerm(inp);
if (IsVarTerm(t)) {
CELL *ptr = VarOfTerm(t);
*ptr = TermFoundVar;
n++;
TrailTerm(TR++) = t;
if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) {
Yap_growtrail(2*n * sizeof(tr_fr_ptr *), true);
}
}
inp = TailOfTerm(inp);
}
WALK_COMPLEX_TERM__({}, {}, FOUND_VAR());
goto restart;
END_WALK();
clean_tr(TR0-n PASS_REGS);
pop_text_stack(lvl);
if (HR != InitialH) {
HR[-1] = TermNil;
return output;
} else {
return TermNil;
}
def_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;
Term t = Deref(ARG2);
if (IsPrimitiveTerm(t))
out = TermNil;
else {
out = vars_within_complex_term(&(t)-1, &(t), Deref(ARG1) PASS_REGS);
}
return Yap_unify(ARG3, out);
}
/* variables within term t */
static Int free_variables_in_term(
USES_REGS1)
{
Term out;
Term t, t0;
Term found_module = 0L;
Term bounds = TermNil;
t = t0 = Deref(ARG1);
while (!IsVarTerm(t) && IsApplTerm(t)) {
Functor f = FunctorOfTerm(t);
if (f == FunctorHat) {
bounds = MkPairTerm(ArgOfTerm(1,t),bounds);
} 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 = new_vars_in_complex_term(&(t)-1, &(t), Yap_TermVariables(bounds, 3) PASS_REGS);
}
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) \
{ \
HR[0] = (CELL)ptd0; \
HR[1] = AbsPair(HR + 2); \
HR += 2; \
*ptd0 = TermRefoundVar; \
}
static Term non_singletons_in_complex_term(CELL * pt0_,
CELL * pt0_end_ USES_REGS) {
WALK_COMPLEX_TERM__({}, {}, FOUND_VAR_AGAIN());
/* 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)
{
goto trail_overflow;
}
TrailTerm(TR++) = (CELL)ptd0;
END_WALK();
clean_tr(TR0 PASS_REGS);
pop_text_stack(lvl);
if (HR != InitialH) {
/* close the list */
HR[-1] = Deref(ARG2);
return AbsPair(InitialH);
} else {
return ARG2;
}
def_overflow();
}
static Int p_non_singletons_in_term(
USES_REGS1) /* non_singletons in term t */
{
Term t;
Term out;
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);
}
return Yap_unify(ARG3,out);
}
static Term numbervar(Int me USES_REGS) {
Term ts[1];
ts[0] = MkIntegerTerm(me);
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 me USES_REGS) {
Term *ts = RepAppl(t);
ts[1] = MkIntegerTerm(me);
}
#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) {
WALK_COMPLEX_TERM__({}, {}, {});
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);
END_WALK();
pop_text_stack(lvl);
return numbv;
def_overflow();
}
Int Yap_NumberVars(Term inp, Int numbv,
bool handle_singles) /*
* numbervariables in term t */
{
CACHE_REGS
Int out;
Term t;
t = Deref(inp);
if (IsPrimitiveTerm(t)) {
return numbv;
} else {
out = numbervars_in_complex_term(&(t)-1, &(t), numbv,
handle_singles PASS_REGS);
}
return out;
}
/** @pred numbervars( _T_,+ _N1_,- _Nn_)
Instantiates each variable in term _T_ to a term of the form:
`$VAR( _I_)`, with _I_ increasing from _N1_ to _Nn_.
*/
static Int p_numbervars(USES_REGS1) {
Term t2 = Deref(ARG2);
Int out;
if (IsVarTerm(t2)) {
Yap_Error(INSTANTIATION_ERROR, t2, "numbervars/3");
return false;
}
if (!IsIntegerTerm(t2)) {
Yap_Error(TYPE_ERROR_INTEGER, t2, "numbervars/3");
return (false);
}
if ((out = Yap_NumberVars(ARG1, IntegerOfTerm(t2), false)) < 0)
return false;
return Yap_unify(ARG3, MkIntegerTerm(out));
}
#define MAX_NUMBERED \
if (FunctorOfTerm(d0) == FunctorDollarVar) { \
Term t1 = ArgOfTerm(1, d0); \
Int i; \
if (IsIntegerTerm(t1) && ((i = IntegerOfTerm(t1)) > *maxp)) \
*maxp = i; \
goto restart; \
}
static int max_numbered_var(CELL * pt0_, CELL * pt0_end_,
Int * maxp USES_REGS) {
WALK_COMPLEX_TERM__({}, MAX_NUMBERED, {});
END_WALK();
/* Do we still have compound terms to visit */
if (to_visit > to_visit0) {
to_visit--;
pt0 = to_visit->pt0;
pt0_end = to_visit->pt0_end;
CELL *ptd0 = to_visit->ptd0;
*ptd0 = to_visit->d0;
}
prune(B PASS_REGS);
pop_text_stack(lvl);
return 0;
def_overflow();
}
static Int MaxNumberedVar(Term inp, UInt arity PASS_REGS) {
Term t = Deref(inp);
if (IsPrimitiveTerm(t)) {
return MkIntegerTerm(0);
} else {
Int res;
Int max;
res = max_numbered_var(&t - 1, &t, &max PASS_REGS) - 1;
if (res < 0)
return -1;
return MkIntegerTerm(max);
}
}
/**
* @pred largest_numbervar( +_Term_, -Max)
*
* Unify _Max_ with the largest integer _I_ such that `$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 UNFOLD_LOOP(Term t, Term * b) {
Term os[2], o;
os[0] = o = MkVarTerm();
os[1] = t;
Term ti = Yap_MkApplTerm(FunctorEq, 2, os), t0 = *b;
*b = MkPairTerm(ti, t0);
return o;
}
typedef struct block_connector {
CELL * parent; //> index in the array;
Term source; //> source;
CELL *copy; //> copy;
CELL header; //> backup of first word of the source data;
CELL reference; //> term used to refer the copy.
} cl_connector;
static Int t_ref(cl_connector *d, cl_connector * q, Int *mep, Int max) {
if ( d >= q && d < q+max) {
*mep = d-q;
return true;
}
return false; //&& d->source == (void *;
}
static Int create_entry(Term t, Int i, Int j, cl_connector * q, Int max) {
Term ref, h, *s, *ostart;
ssize_t n;
// fprintf(stderr,"[%ld,%ld]/%ld, %lx\n",i,j,max,t);
restart:
// first time, create a new term
if (IsVarTerm(t)) {
return -1;
}
if (IsPairTerm(t)) {
Int me;
s = RepPair(t);
h = s[0];
if (IsAtomTerm(h) && t_ref((cl_connector *)AtomOfTerm(h), q, &me, max)) {
return me;
}
n = 2;
ostart = HR;
ref = AbsPair(ostart);
HR += 2;
} else if (IsApplTerm(t)) {
Int me;
h = (CELL)FunctorOfTerm(t);
if (IsExtensionFunctor((Functor)h)) {
return -1;
}
if (IsAtomTerm(h) &&
t_ref((cl_connector*)AtomOfTerm(h),q,&me,max)) {
return me;
}
n = ArityOfFunctor((Functor)h);
s = RepAppl(t);
ostart = HR;
ref = AbsAppl(ostart);
*ostart++ = s[0];
HR=ostart+n;
} else {
Int me;
if (IsAtomTerm(t) && t_ref((cl_connector*)AtomOfTerm(t),q,&me,max)) {
t = q[me].source;
goto restart;
} else {
return -1;
}
}
q[max].header = h;
q[max].parent = q[i].copy+j;
q[i].copy[j] = ref;
q[max].source = t;
q[max].copy = ostart;
q[max].reference = ref;
s[0] = MkAtomTerm((void*)(q+max));
return max+1;
}
Int cp_link(Term t, Int i, Int j, cl_connector * q, Int max, CELL * tailp) {
Int me;
t = Deref(t);
if ((me = create_entry(t, i, j, q, max)) < max) {
if (me < 0) {
q[i].copy[j] = t;
return max;
}
Term ref = q[me].reference;
if (IsVarTerm(ref)) {
q[i].copy[j] = ref;
// fprintf(stderr," - %p\n", ref);
}
else {
Term v = UNFOLD_LOOP(ref, tailp);
q[i].copy[j] = v;
if (me)
q[me].parent[0] = v;
q[me].reference = v;
}
return max;
}
return me;
}
Term Yap_BreakCycles(Term inp, UInt arity, Term * listp USES_REGS) {
int lvl = push_text_stack();
Term t = Deref(inp);
ssize_t qsize = 2048, qlen = 0;
cl_connector *q = Malloc(qsize * sizeof(cl_connector));
Term *s;
Int i = 0;
HB = HR;
qlen = 0;
Term t0 = MkPairTerm(t, TermNil);
q[0].copy = HR;
HR+=2;
if (IsVarTerm(t) || IsPrimitiveTerm(t)) {
return t;
} else {
// initialization
qlen = create_entry(Deref(t0), i, 0, q, qlen);
while(i<qlen) {
arity_t n, j;
if (IsPairTerm(q[i].source)) {
s = RepPair(q[i].source);
n = 2;
// fetch using header field.
qlen = cp_link(q[i].header, i, 0, q, qlen, listp);
// fetch using standard access
qlen = cp_link(s[1], i, 1, q, qlen, listp);
} else {
s = RepAppl(q[i].source) + 1;
n = ArityOfFunctor((Functor)q[i].header);
for (j = 0; j < n; j++) {
qlen = cp_link(s[j], i, j, q, qlen, listp);
}
}
i++;
}
}
for (i=0; i< qlen; i++) {
CELL *p = IsPairTerm(q[i].source) ? RepPair(q[i].source) : RepAppl(q[i].source);
p[0] = (q[i].header);
}
pop_text_stack(lvl);
HB = B->cp_h;
return HeadOfTerm( q[0].reference );
}
/** @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 rational_term_to_tree(USES_REGS1) {
Term t = Deref(ARG1);
Term l = Deref(ARG4);
if (IsVarTerm(l))
Yap_unify(l, MkVarTerm());
return Yap_unify(Yap_BreakCycles(t, 4, &l PASS_REGS), ARG2) &&
Yap_unify(l, ARG3);
}
void Yap_InitTermCPreds(void) {
Yap_InitCPred("cycles_in_term", 2, cycles_in_term, 0);
Yap_InitCPred("term_variables", 2, term_variables, 0);
Yap_InitCPred("term_variables", 3, term_variables3, 0);
Yap_InitCPred("$variables_in_term", 3, variables_in_term, 0);
Yap_InitCPred("$free_variables_in_term", 3, free_variables_in_term, 0);
Yap_InitCPred("free_variables_in_term", 3, free_variables_in_term, 0);
Yap_InitCPred("term_attvars", 2, 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("rational_term_to_tree", 4, rational_term_to_tree, 0);
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);
}
//@}
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