static Int
p_binary_is(void)
{ /* X is Y */
Term t = Deref(ARG2);
Term t1, t2;
if (IsVarTerm(t)) {
Yap_ArithError(INSTANTIATION_ERROR,t, "X is Y");
return(FALSE);
}
t1 = Yap_Eval(Deref(ARG3));
if (!Yap_FoundArithError(t1, ARG3)) {
return FALSE;
}
t2 = Yap_Eval(Deref(ARG4));
if (!Yap_FoundArithError(t2, ARG4)) {
return FALSE;
}
if (IsIntTerm(t)) {
Term tout = Yap_FoundArithError(eval2(IntOfTerm(t), t1, t2), 0L);
if (!tout)
return FALSE;
return Yap_unify_constant(ARG1,tout);
}
if (IsAtomTerm(t)) {
Atom name = AtomOfTerm(t);
ExpEntry *p;
Term out;
if (EndOfPAEntr(p = RepExpProp(Yap_GetExpProp(name, 2)))) {
Term ti[2];
/* error */
ti[0] = t;
ti[1] = MkIntTerm(1);
t = Yap_MkApplTerm(FunctorSlash, 2, ti);
Yap_Error(TYPE_ERROR_EVALUABLE, t,
"functor %s/%d for arithmetic expression",
RepAtom(name)->StrOfAE,2);
P = FAILCODE;
return(FALSE);
}
if (!(out=Yap_FoundArithError(eval2(p->FOfEE, t1, t2), 0L)))
return FALSE;
return Yap_unify_constant(ARG1,out);
}
return FALSE;
}
static Int
p_binary_op_as_integer(void)
{ /* X is Y */
Term t = Deref(ARG1);
if (IsVarTerm(t)) {
Yap_Error(INSTANTIATION_ERROR,t, "X is Y");
return(FALSE);
}
if (IsIntTerm(t)) {
return Yap_unify_constant(ARG2,t);
}
if (IsAtomTerm(t)) {
Atom name = AtomOfTerm(t);
ExpEntry *p;
if (EndOfPAEntr(p = RepExpProp(Yap_GetExpProp(name, 2)))) {
return Yap_unify(ARG1,ARG2);
}
return Yap_unify_constant(ARG2,MkIntTerm(p->FOfEE));
}
return(FALSE);
}
static Term
Eval(Term t USES_REGS)
{
if (IsVarTerm(t)) {
return Yap_ArithError(INSTANTIATION_ERROR,t,"in arithmetic");
} else if (IsNumTerm(t)) {
return t;
} else if (IsAtomTerm(t)) {
ExpEntry *p;
Atom name = AtomOfTerm(t);
if (EndOfPAEntr(p = RepExpProp(Yap_GetExpProp(name, 0)))) {
/* error */
Term ti[2];
/* error */
ti[0] = t;
ti[1] = MkIntTerm(0);
t = Yap_MkApplTerm(FunctorSlash, 2, ti);
return Yap_ArithError(TYPE_ERROR_EVALUABLE, t,
"atom %s in arithmetic expression",
RepAtom(name)->StrOfAE);
}
return Yap_eval_atom(p->FOfEE);
} else if (IsApplTerm(t)) {
Functor fun = FunctorOfTerm(t);
if (fun == FunctorString) {
const char *s = StringOfTerm(t);
if (s[1] == '\0')
return MkIntegerTerm(s[0]);
return Yap_ArithError(TYPE_ERROR_EVALUABLE, t,
"string in arithmetic expression");
} else if ((Atom)fun == AtomFoundVar) {
return Yap_ArithError(TYPE_ERROR_EVALUABLE, TermNil,
"cyclic term in arithmetic expression");
} else {
Int n = ArityOfFunctor(fun);
Atom name = NameOfFunctor(fun);
ExpEntry *p;
Term t1, t2;
if (EndOfPAEntr(p = RepExpProp(Yap_GetExpProp(name, n)))) {
Term ti[2];
/* error */
ti[0] = t;
ti[1] = MkIntegerTerm(n);
t = Yap_MkApplTerm(FunctorSlash, 2, ti);
return Yap_ArithError(TYPE_ERROR_EVALUABLE, t,
"functor %s/%d for arithmetic expression",
RepAtom(name)->StrOfAE,n);
}
if (p->FOfEE == op_power && p->ArityOfEE == 2) {
t2 = ArgOfTerm(2, t);
if (IsPairTerm(t2)) {
return get_matrix_element(ArgOfTerm(1, t), t2 PASS_REGS);
}
}
*RepAppl(t) = (CELL)AtomFoundVar;
t1 = Eval(ArgOfTerm(1,t) PASS_REGS);
if (t1 == 0L) {
*RepAppl(t) = (CELL)fun;
return FALSE;
}
if (n == 1) {
*RepAppl(t) = (CELL)fun;
return Yap_eval_unary(p->FOfEE, t1);
}
t2 = Eval(ArgOfTerm(2,t) PASS_REGS);
*RepAppl(t) = (CELL)fun;
if (t2 == 0L)
return FALSE;
return Yap_eval_binary(p->FOfEE,t1,t2);
}
} /* else if (IsPairTerm(t)) */ {
if (TailOfTerm(t) != TermNil) {
return Yap_ArithError(TYPE_ERROR_EVALUABLE, t,
"string must contain a single character to be evaluated as an arithmetic expression");
}
return Eval(HeadOfTerm(t) PASS_REGS);
}
}
