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simple check for all var arguments

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This commit is contained in:
Vítor Santos Costa 2013-06-07 09:26:21 -05:00
parent b6b44c655f
commit 5303f2f479
1 changed files with 38 additions and 0 deletions
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38
C/utilpreds.c
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@ -5541,6 +5541,43 @@ p_skip_list4( USES_REGS1 ) {
Yap_unify(t, ARG4);
}
static Int
p_free_arguments( USES_REGS1 )
{
Term t = Deref(ARG1);
if (IsVarTerm(t))
return FALSE;
if (IsAtomTerm(t) || IsIntTerm(t))
return TRUE;
if (IsPairTerm(t)) {
Term th = HeadOfTerm(t);
Term tl = TailOfTerm(t);
return IsVarTerm(th) && IsVarTerm(tl) && th != tl;
} else {
Functor f = FunctorOfTerm(t);
UInt i, ar;
Int ret = TRUE;
if (IsExtensionFunctor(f))
return TRUE;
ar = ArityOfFunctor(f);
for (i = 1 ; i <= ar; i++) {
Term ta = ArgOfTerm(i, t);
Int j;
ret = IsVarTerm(ta);
if (!ret) break;
/* stupid quadractic algorithm, but needs no testing for overflows */
for (j = 1 ; j < i; j++) {
ret = ArgOfTerm(j, t) != ta;
if (!ret) break;
}
if (!ret) break;
}
return ret;
}
}
void Yap_InitUtilCPreds(void)
{
CACHE_REGS
@ -5565,6 +5602,7 @@ void Yap_InitUtilCPreds(void)
/* use this carefully */
Yap_InitCPred("$skip_list", 3, p_skip_list, SafePredFlag|TestPredFlag);
Yap_InitCPred("$skip_list", 4, p_skip_list4, SafePredFlag|TestPredFlag);
Yap_InitCPred("$free_arguments", 1, p_free_arguments, TestPredFlag);
CurrentModule = TERMS_MODULE;
Yap_InitCPred("variable_in_term", 2, p_var_in_term, 0);
Yap_InitCPred("term_hash", 4, p_term_hash, 0);