BOOL cont_TermEqual(CONTEXT Context1, TERM Term1, CONTEXT Context2, TERM Term2)
/*********************************************************
INPUT: Two terms and two contexts.
RETURNS: TRUE iff the two terms are equal, where
variables are interpreted with respect to
the bindings in the contexts.
********************************************************/
{
#ifdef CHECK
if (!(term_IsTerm(Term1) && term_IsTerm(Term2))) {
misc_StartErrorReport();
misc_ErrorReport("\n In cont_TermEqual: Input terms are corrupted.\n");
misc_FinishErrorReport();
}
#endif
Term1 = cont_Deref(&Context1,Term1);
Term2 = cont_Deref(&Context2,Term2);
if (!term_EqualTopSymbols(Term1, Term2))
return FALSE;
else if (term_ArgumentList(Term1)) {
LIST Scan1, Scan2;
for (Scan1=term_ArgumentList(Term1), Scan2=term_ArgumentList(Term2);
list_Exist(Scan1) && list_Exist(Scan2);
Scan1=list_Cdr(Scan1), Scan2=list_Cdr(Scan2))
if (!cont_TermEqual(Context1,list_Car(Scan1), Context2,list_Car(Scan2)))
return FALSE;
return (list_Empty(Scan1) ? list_Empty(Scan2) : FALSE);
} else
return TRUE;
}
BOOL cont_TermEqual(CONTEXT GlobalContext1, CONTEXT TermContext1, TERM Term1,
CONTEXT GlobalContext2, CONTEXT TermContext2, TERM Term2)
/*********************************************************
INPUT: Two terms and two local contexts for the terms and
two global contexts
RETURNS: TRUE iff the two terms are equal, where
variables are interpreted with respect to
the bindings in the contexts.
CAUTION: Variables of <Term1> and <Term2> are bound in
<TermContext1> and <TermContext2> respectively and
the index variables are bound in <GlobalContext1>
and <GlobalContext2> respectively.
********************************************************/
{
#ifdef CHECK
if (!(term_IsTerm(Term1) && term_IsTerm(Term2))) {
misc_StartErrorReport();
misc_ErrorReport("\n In cont_TermEqual: Input terms are corrupted.\n");
misc_FinishErrorReport();
}
#endif
Term1 = cont_Deref(GlobalContext1,&TermContext1,Term1);
Term2 = cont_Deref(GlobalContext2,&TermContext2,Term2);
if (!term_EqualTopSymbols(Term1, Term2))
return FALSE;
else if (term_ArgumentList(Term1)) {
LIST Scan1, Scan2;
for (Scan1=term_ArgumentList(Term1), Scan2=term_ArgumentList(Term2);
list_Exist(Scan1) && list_Exist(Scan2);
Scan1=list_Cdr(Scan1), Scan2=list_Cdr(Scan2))
if (!cont_TermEqual(GlobalContext1, TermContext1,list_Car(Scan1),
GlobalContext2, TermContext2,list_Car(Scan2)))
return FALSE;
return (list_Empty(Scan1) ? list_Empty(Scan2) : FALSE);
} else
return TRUE;
}
static BOOL kbo_ContGreaterCompareStruc(CONTEXT Context1, TERM Term1,
CONTEXT Context2, TERM Term2)
/**************************************************************
INPUT: Two contexts and two terms where the kbo-variable condition
for <Term1> and <Term2> is satisfied as well as the
weight difference between the terms is zero.
RETURNS: TRUE if Term1 is greater than Term2.
The Terms are interpreted with respect to the contexts.
CAUTION: The precedence from the order module is used to determine
the precedence of symbols!
***************************************************************/
{
LIST Scan1,Scan2;
SYMBOL Top1,Top2;
Term1 = cont_Deref(&Context1,Term1);
Term2 = cont_Deref(&Context2,Term2);
Top1 = term_TopSymbol(Term1);
Top2 = term_TopSymbol(Term2);
if (symbol_IsStandardVariable(Top1)) {
if (symbol_IsStandardVariable(Top2))
return FALSE;
else
return FALSE;
}
else if (symbol_IsStandardVariable(Top2) ||
symbol_PrecedenceGreater(ord_PRECEDENCE, Top1, Top2))
return TRUE;
else if (Top1 == Top2) {
int RecWeightDiff;
BOOL T1VarCond, T2VarCond;
TERM RecTerm1,RecTerm2;
Scan1 = term_ArgumentList(Term1);
Scan2 = term_ArgumentList(Term2);
if (symbol_HasProperty(Top1,ORDRIGHT)) {
int i;
for (i = symbol_Arity(Top1);
i > 0 && cont_TermEqual(Context1,list_NthElement(Scan1,i),
Context2,list_NthElement(Scan2,i));
i--);
if (i > 0) {
RecTerm1 = cont_Deref(&Context1,list_NthElement(Scan1,i));
RecTerm2 = cont_Deref(&Context2,list_NthElement(Scan2,i));
}
else
return FALSE;
}
else {
while (!list_Empty(Scan1) && cont_TermEqual(Context1,list_Car(Scan1),Context2,list_Car(Scan2))) {
Scan1 = list_Cdr(Scan1);
Scan2 = list_Cdr(Scan2);
}
if (list_Empty(Scan1)) /* Implies that list_Empty(Scan2) */
return FALSE;
else {
RecTerm1 = cont_Deref(&Context1,list_Car(Scan1));
RecTerm2 = cont_Deref(&Context2,list_Car(Scan2));
}
}
RecWeightDiff = kbo_ContCompVarCondAndWeight(Context1,RecTerm1,&T1VarCond,
Context2,RecTerm2,&T2VarCond);
if (T1VarCond) {
if (RecWeightDiff > 0)
return TRUE;
else if (RecWeightDiff == 0)
return kbo_ContGreaterCompareStruc(Context1, RecTerm1, Context2, RecTerm2);
}
}
return FALSE;
}
