574 lines
13 KiB
C
574 lines
13 KiB
C
/*************************************************************************
|
|
* *
|
|
* YAP Prolog *
|
|
* *
|
|
* Yap Prolog was developed at NCCUP - Universidade do Porto *
|
|
* *
|
|
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
|
|
* *
|
|
**************************************************************************
|
|
* *
|
|
* File: corout.c *
|
|
* Last rev: *
|
|
* mods: *
|
|
* comments: Co-routining from within YAP *
|
|
* *
|
|
*************************************************************************/
|
|
#ifdef SCCS
|
|
static char SccsId[]="%W% %G%";
|
|
#endif
|
|
|
|
#include "Yap.h"
|
|
#include "Yatom.h"
|
|
#include "YapHeap.h"
|
|
#include "heapgc.h"
|
|
#include "attvar.h"
|
|
#ifndef NULL
|
|
#define NULL (void *)0
|
|
#endif
|
|
|
|
#ifdef COROUTINING
|
|
|
|
/* check if variable was there */
|
|
static Term AddVarIfNotThere(Term var , Term dest)
|
|
{
|
|
Term test = dest;
|
|
while (test != TermNil) {
|
|
if ((RepPair(test))[0] == var) return(dest);
|
|
else test = (RepPair(test))[1];
|
|
}
|
|
return(MkPairTerm(var,dest));
|
|
}
|
|
|
|
|
|
/* This routine verifies whether two complex structures can unify. */
|
|
static int can_unify_complex(register CELL *pt0,
|
|
register CELL *pt0_end,
|
|
register CELL *pt1,
|
|
Term *Vars)
|
|
{
|
|
|
|
/* This is really just unification, folks */
|
|
tr_fr_ptr saved_TR;
|
|
CELL *saved_HB;
|
|
choiceptr saved_B;
|
|
|
|
register CELL **to_visit = (CELL **)Yap_PreAllocCodeSpace();
|
|
CELL **to_visit_base = to_visit;
|
|
|
|
/* make sure to trail all bindings */
|
|
saved_TR = TR;
|
|
saved_B = B;
|
|
saved_HB = HB;
|
|
HB = H;
|
|
|
|
loop:
|
|
while (pt0 < pt0_end) {
|
|
register CELL d0, d1;
|
|
++ pt0;
|
|
++ pt1;
|
|
d0 = Derefa(pt0);
|
|
d1 = Derefa(pt1);
|
|
if (IsVarTerm(d0)) {
|
|
if (IsVarTerm(d1)) {
|
|
if (d0 != d1) {
|
|
/* we need to suspend on both variables ! */
|
|
*Vars = AddVarIfNotThere(d0, AddVarIfNotThere(d1,*Vars));
|
|
/* bind the two variables, we would have to do that to unify
|
|
them */
|
|
if (d1 > d0) { /* youngest */
|
|
/* we don't want to wake up goals */
|
|
Bind_Global((CELL *)d1, d0);
|
|
} else {
|
|
Bind_Global((CELL *)d0, d1);
|
|
}
|
|
}
|
|
/* continue the loop */
|
|
continue;
|
|
}
|
|
else {
|
|
/* oh no, some more variables! */
|
|
*Vars = AddVarIfNotThere(d0, *Vars);
|
|
}
|
|
/* now bind it */
|
|
Bind_Global((CELL *)d0, d1);
|
|
/* continue the loop */
|
|
} else if (IsVarTerm(d1)) {
|
|
*Vars = AddVarIfNotThere(d1, *Vars);
|
|
/* and bind it */
|
|
Bind_Global((CELL *)d1, d0);
|
|
/* continue the loop */
|
|
} else {
|
|
if (d0 == d1) continue;
|
|
if (IsAtomOrIntTerm(d0) || IsAtomOrIntTerm(d1)) {
|
|
if (d0 != d1) goto comparison_failed;
|
|
/* else continue the loop */
|
|
}
|
|
else if (IsPairTerm(d0)) {
|
|
if (!IsPairTerm(d1)) goto comparison_failed;
|
|
#ifdef RATIONAL_TREES
|
|
to_visit[0] = pt0;
|
|
to_visit[1] = pt0_end;
|
|
to_visit[2] = pt1;
|
|
to_visit[3] = (CELL *)*pt0;
|
|
to_visit += 4;
|
|
*pt0 = d1;
|
|
#else
|
|
/* store the terms to visit */
|
|
if (pt0 < pt0_end) {
|
|
to_visit[0] = pt0;
|
|
to_visit[1] = pt0_end;
|
|
to_visit[2] = pt1;
|
|
to_visit += 3;
|
|
}
|
|
#endif
|
|
pt0 = RepPair(d0) - 1;
|
|
pt0_end = RepPair(d0) + 1;
|
|
pt1 = RepPair(d1) - 1;
|
|
continue;
|
|
}
|
|
else if (IsApplTerm(d0)) {
|
|
register Functor f;
|
|
register CELL *ap2, *ap3;
|
|
if (!IsApplTerm(d1)) {
|
|
goto comparison_failed;
|
|
} else {
|
|
/* store the terms to visit */
|
|
ap2 = RepAppl(d0);
|
|
ap3 = RepAppl(d1);
|
|
f = (Functor)(*ap2);
|
|
/* compare functors */
|
|
if (f != (Functor)*ap3) {
|
|
goto comparison_failed;
|
|
}
|
|
if (IsExtensionFunctor(f)) {
|
|
switch((CELL)f) {
|
|
case (CELL)FunctorDBRef:
|
|
if (d0 == d1) continue;
|
|
goto comparison_failed;
|
|
case (CELL)FunctorLongInt:
|
|
if (ap2[1] == ap3[1]) continue;
|
|
goto comparison_failed;
|
|
case (CELL)FunctorDouble:
|
|
if (FloatOfTerm(d0) == FloatOfTerm(d1)) continue;
|
|
goto comparison_failed;
|
|
#ifdef USE_GMP
|
|
case (CELL)FunctorBigInt:
|
|
if (mpz_cmp(Yap_BigIntOfTerm(d0),Yap_BigIntOfTerm(d1)) == 0) continue;
|
|
goto comparison_failed;
|
|
#endif /* USE_GMP */
|
|
default:
|
|
goto comparison_failed;
|
|
}
|
|
}
|
|
#ifdef RATIONAL_TREES
|
|
to_visit[0] = pt0;
|
|
to_visit[1] = pt0_end;
|
|
to_visit[2] = pt1;
|
|
to_visit[3] = (CELL *)*pt0;
|
|
to_visit += 4;
|
|
*pt0 = d1;
|
|
#else
|
|
/* store the terms to visit */
|
|
if (pt0 < pt0_end) {
|
|
to_visit[0] = pt0;
|
|
to_visit[1] = pt0_end;
|
|
to_visit[2] = pt1;
|
|
to_visit += 3;
|
|
}
|
|
#endif
|
|
d0 = ArityOfFunctor(f);
|
|
pt0 = ap2;
|
|
pt0_end = ap2 + d0;
|
|
pt1 = ap3;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
/* Do we still have compound terms to visit */
|
|
if (to_visit > (CELL **)to_visit_base) {
|
|
#ifdef RATIONAL_TREES
|
|
to_visit -= 4;
|
|
pt0 = to_visit[0];
|
|
pt0_end = to_visit[1];
|
|
pt1 = to_visit[2];
|
|
*pt0 = (CELL)to_visit[3];
|
|
#else
|
|
to_visit -= 3;
|
|
pt0 = to_visit[0];
|
|
pt0_end = to_visit[1];
|
|
pt1 = to_visit[2];
|
|
#endif
|
|
goto loop;
|
|
}
|
|
/* success */
|
|
Yap_ReleasePreAllocCodeSpace((ADDR)to_visit);
|
|
/* restore B, and later HB */
|
|
B = saved_B;
|
|
HB = saved_HB;
|
|
/* untrail all bindings made by IUnify */
|
|
while (TR != saved_TR) {
|
|
pt1 = (CELL *)(TrailTerm(--TR));
|
|
RESET_VARIABLE(pt1);
|
|
}
|
|
return(TRUE);
|
|
|
|
comparison_failed:
|
|
/* failure */
|
|
Yap_ReleasePreAllocCodeSpace((ADDR)to_visit);
|
|
#ifdef RATIONAL_TREES
|
|
while (to_visit > (CELL **)to_visit_base) {
|
|
to_visit -= 4;
|
|
pt0 = to_visit[0];
|
|
pt0_end = to_visit[1];
|
|
pt1 = to_visit[2];
|
|
*pt0 = (CELL)to_visit[3];
|
|
}
|
|
#endif
|
|
/* restore B, and later HB */
|
|
B = saved_B;
|
|
HB = saved_HB;
|
|
/* the system will take care of TR for me, no need to worry here! */
|
|
return(FALSE);
|
|
}
|
|
|
|
static int
|
|
can_unify(Term t1, Term t2, Term *Vars)
|
|
{
|
|
t1 = Deref(t1);
|
|
t2 = Deref(t2);
|
|
if (t1 == t2) {
|
|
*Vars = TermNil;
|
|
return TRUE;
|
|
}
|
|
if (IsVarTerm(t1)) {
|
|
/* we know for sure they can't be different */
|
|
if (IsVarTerm(t2)) {
|
|
/* we need to suspend on both variables because otherwise
|
|
Y = susp(_) would not wakeup susp ! */
|
|
*Vars = MkPairTerm(t1,MkPairTerm(t2,TermNil));
|
|
return TRUE;
|
|
} else {
|
|
*Vars = MkPairTerm(t1,TermNil);
|
|
return TRUE;
|
|
}
|
|
} else if (IsVarTerm(t2)) {
|
|
/* wait until t2 is bound */
|
|
*Vars = MkPairTerm(t2,TermNil);
|
|
return TRUE;
|
|
}
|
|
/* Two standard terms at last! */
|
|
if (IsAtomOrIntTerm(t1) || IsAtomOrIntTerm(t2)) {
|
|
/* Two primitive terms can only be equal if they are
|
|
the same. If they are, $eq succeeds without further ado.
|
|
*/
|
|
if (t1 != t2)
|
|
return FALSE;
|
|
else {
|
|
*Vars = TermNil;
|
|
return TRUE;
|
|
}
|
|
} else if (IsPairTerm(t1)) {
|
|
if (IsPairTerm(t2)) {
|
|
return(can_unify_complex(RepPair(t1)-1, RepPair(t1)+1,
|
|
RepPair(t2)-1, Vars));
|
|
} else return FALSE;
|
|
} else {
|
|
Functor f = FunctorOfTerm(t1);
|
|
if (f != FunctorOfTerm(t2))
|
|
return FALSE;
|
|
if (IsExtensionFunctor(f)) {
|
|
switch((CELL)f) {
|
|
case (CELL)FunctorDBRef:
|
|
if (t1 == t2) return FALSE;
|
|
return FALSE;
|
|
case (CELL)FunctorLongInt:
|
|
if (RepAppl(t1)[1] == RepAppl(t2)[1]) return(TRUE);
|
|
return FALSE;
|
|
case (CELL)FunctorDouble:
|
|
if (FloatOfTerm(t1) == FloatOfTerm(t2)) return(TRUE);
|
|
return FALSE;
|
|
#ifdef USE_GMP
|
|
case (CELL)FunctorBigInt:
|
|
if (mpz_cmp(Yap_BigIntOfTerm(t1),Yap_BigIntOfTerm(t2)) == 0) return(TRUE);
|
|
return(FALSE);
|
|
#endif /* USE_GMP */
|
|
default:
|
|
return FALSE;
|
|
}
|
|
}
|
|
/* Two complex terms with the same functor */
|
|
return can_unify_complex(RepAppl(t1),
|
|
RepAppl(t1)+ArityOfFunctor(f),
|
|
RepAppl(t2), Vars);
|
|
}
|
|
}
|
|
|
|
/* This routine verifies whether a complex has variables. */
|
|
static int non_ground_complex(register CELL *pt0,
|
|
register CELL *pt0_end,
|
|
Term *Var)
|
|
{
|
|
|
|
register CELL **to_visit = (CELL **)Yap_PreAllocCodeSpace();
|
|
CELL **to_visit_base = to_visit;
|
|
|
|
loop:
|
|
while (pt0 < pt0_end) {
|
|
register CELL d0;
|
|
++ pt0;
|
|
d0 = Derefa(pt0);
|
|
if (IsVarTerm(d0)) {
|
|
*Var = d0;
|
|
goto var_found;
|
|
}
|
|
if (IsPairTerm(d0)) {
|
|
if (to_visit + 1024 >= (CELL **)AuxSp) {
|
|
goto aux_overflow;
|
|
}
|
|
#ifdef RATIONAL_TREES
|
|
to_visit[0] = pt0;
|
|
to_visit[1] = pt0_end;
|
|
to_visit[2] = (CELL *)*pt0;
|
|
to_visit += 3;
|
|
*pt0 = TermNil;
|
|
#else
|
|
/* store the terms to visit */
|
|
if (pt0 < pt0_end) {
|
|
to_visit[0] = pt0;
|
|
to_visit[1] = pt0_end;
|
|
to_visit += 2;
|
|
}
|
|
#endif
|
|
pt0 = RepPair(d0) - 1;
|
|
pt0_end = RepPair(d0) + 1;
|
|
}
|
|
else if (IsApplTerm(d0)) {
|
|
register Functor f;
|
|
register CELL *ap2;
|
|
|
|
/* store the terms to visit */
|
|
ap2 = RepAppl(d0);
|
|
f = (Functor)(*ap2);
|
|
|
|
if (IsExtensionFunctor(f)) {
|
|
continue;
|
|
}
|
|
if (to_visit + 1024 >= (CELL **)AuxSp) {
|
|
goto aux_overflow;
|
|
}
|
|
#ifdef RATIONAL_TREES
|
|
to_visit[0] = pt0;
|
|
to_visit[1] = pt0_end;
|
|
to_visit[2] = (CELL *)*pt0;
|
|
to_visit += 3;
|
|
*pt0 = TermNil;
|
|
#else
|
|
/* store the terms to visit */
|
|
if (pt0 < pt0_end) {
|
|
to_visit[0] = pt0;
|
|
to_visit[1] = pt0_end;
|
|
to_visit += 2;
|
|
}
|
|
#endif
|
|
d0 = ArityOfFunctor(f);
|
|
pt0 = ap2;
|
|
pt0_end = ap2 + d0;
|
|
}
|
|
/* just continue the loop */
|
|
}
|
|
|
|
/* Do we still have compound terms to visit */
|
|
if (to_visit > (CELL **)to_visit_base) {
|
|
#ifdef RATIONAL_TREES
|
|
to_visit -= 3;
|
|
pt0 = to_visit[0];
|
|
pt0_end = to_visit[1];
|
|
*pt0 = (CELL)to_visit[2];
|
|
#else
|
|
to_visit -= 2;
|
|
pt0 = to_visit[0];
|
|
pt0_end = to_visit[1];
|
|
#endif
|
|
goto loop;
|
|
}
|
|
|
|
/* the term is ground */
|
|
Yap_ReleasePreAllocCodeSpace((ADDR)to_visit);
|
|
return FALSE;
|
|
|
|
var_found:
|
|
/* the term is non-ground */
|
|
Yap_ReleasePreAllocCodeSpace((ADDR)to_visit);
|
|
#ifdef RATIONAL_TREES
|
|
while (to_visit > (CELL **)to_visit_base) {
|
|
to_visit -= 3;
|
|
pt0 = to_visit[0];
|
|
pt0_end = to_visit[1];
|
|
*pt0 = (CELL)to_visit[2];
|
|
}
|
|
#endif
|
|
/* the system will take care of TR for me, no need to worry here! */
|
|
return TRUE;
|
|
|
|
aux_overflow:
|
|
/* unwind stack */
|
|
Yap_ReleasePreAllocCodeSpace((ADDR)to_visit);
|
|
#ifdef RATIONAL_TREES
|
|
while (to_visit > (CELL **)to_visit_base) {
|
|
to_visit -= 3;
|
|
pt0 = to_visit[0];
|
|
*pt0 = (CELL)to_visit[2];
|
|
}
|
|
#endif
|
|
return -1;
|
|
}
|
|
|
|
static int
|
|
non_ground(Term t, Term *Var)
|
|
{
|
|
int out = -1;
|
|
while (out < 0) {
|
|
t = Deref(t);
|
|
if (IsVarTerm(t)) {
|
|
/* we found a variable */
|
|
*Var = t;
|
|
return TRUE;
|
|
}
|
|
if (IsPrimitiveTerm(t)) {
|
|
return FALSE;
|
|
} else if (IsPairTerm(t)) {
|
|
out = non_ground_complex(RepPair(t)-1, RepPair(t)+1, Var);
|
|
if (out >= 0)
|
|
return out;
|
|
} else {
|
|
Functor f = FunctorOfTerm(t);
|
|
if (IsExtensionFunctor(f)) {
|
|
return FALSE;
|
|
}
|
|
out = non_ground_complex(RepAppl(t),
|
|
RepAppl(t)+ArityOfFunctor(FunctorOfTerm(t)),
|
|
Var);
|
|
if (out >= 0)
|
|
return out;
|
|
}
|
|
if (!Yap_ExpandPreAllocCodeSpace(0, NULL, TRUE)) {
|
|
Yap_Error(OUT_OF_AUXSPACE_ERROR, ARG1, "overflow in ground");
|
|
return FALSE;
|
|
}
|
|
}
|
|
return FALSE;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* check whether the two terms unify and return what variables should
|
|
be bound before the terms are exactly equal */
|
|
static Int p_can_unify(void)
|
|
{
|
|
#ifdef COROUTINING
|
|
Term r = TermNil;
|
|
if (!can_unify(ARG1, ARG2, &r))
|
|
return FALSE;
|
|
return Yap_unify(ARG3, r);
|
|
#else
|
|
return FALSE;
|
|
#endif
|
|
}
|
|
|
|
/* if the term is not ground return a variable in the term */
|
|
static Int p_non_ground(void)
|
|
{
|
|
#ifdef COROUTINING
|
|
Term r = TermNil;
|
|
if (!non_ground(ARG1, &r))
|
|
return(FALSE);
|
|
return (Yap_unify(ARG2, r));
|
|
#else
|
|
return(FALSE);
|
|
#endif
|
|
}
|
|
|
|
/* if the term is not ground return a variable in the term */
|
|
static Int p_coroutining(void)
|
|
{
|
|
#ifdef COROUTINING
|
|
return(TRUE);
|
|
#else
|
|
return(FALSE);
|
|
#endif
|
|
}
|
|
|
|
#if COROUTINING
|
|
static Term
|
|
ListOfWokenGoals(void) {
|
|
return Yap_ReadTimedVar(WokenGoals);
|
|
}
|
|
|
|
Term
|
|
Yap_ListOfWokenGoals(void) {
|
|
return ListOfWokenGoals();
|
|
}
|
|
#endif
|
|
|
|
/* return a list of awoken goals */
|
|
static Int p_awoken_goals(void)
|
|
{
|
|
#ifdef COROUTINING
|
|
Term WGs = Yap_ReadTimedVar(WokenGoals);
|
|
if (WGs == TermNil) {
|
|
return(FALSE);
|
|
}
|
|
WGs = ListOfWokenGoals();
|
|
Yap_UpdateTimedVar(WokenGoals, TermNil);
|
|
return(Yap_unify(ARG1,WGs));
|
|
#else
|
|
return(FALSE);
|
|
#endif
|
|
}
|
|
|
|
static Int
|
|
p_yap_has_rational_trees(void)
|
|
{
|
|
#if RATIONAL_TREES
|
|
return TRUE;
|
|
#else
|
|
return FALSE;
|
|
#endif
|
|
}
|
|
|
|
static Int
|
|
p_yap_has_coroutining(void)
|
|
{
|
|
#if COROUTINING
|
|
return TRUE;
|
|
#else
|
|
return FALSE;
|
|
#endif
|
|
}
|
|
|
|
void
|
|
Yap_InitCoroutPreds(void)
|
|
{
|
|
#ifdef COROUTINING
|
|
Atom at;
|
|
PredEntry *pred;
|
|
|
|
at = AtomWakeUpGoal;
|
|
pred = RepPredProp(PredPropByFunc(Yap_MkFunctor(at, 2),0));
|
|
WakeUpCode = pred;
|
|
#endif
|
|
Yap_InitAttVarPreds();
|
|
Yap_InitCPred("$yap_has_rational_trees", 0, p_yap_has_rational_trees, SafePredFlag|HiddenPredFlag);
|
|
Yap_InitCPred("$yap_has_coroutining", 0, p_yap_has_coroutining, SafePredFlag|HiddenPredFlag);
|
|
Yap_InitCPred("$can_unify", 3, p_can_unify, SafePredFlag|HiddenPredFlag);
|
|
Yap_InitCPred("$non_ground", 2, p_non_ground, SafePredFlag|HiddenPredFlag);
|
|
Yap_InitCPred("$coroutining", 0, p_coroutining, SafePredFlag|HiddenPredFlag);
|
|
Yap_InitCPred("$awoken_goals", 1, p_awoken_goals, SafePredFlag|HiddenPredFlag);
|
|
}
|
|
|
|
|