static ord_RESULT rpos_LexGreaterEqual(TERM T1, TERM T2, BOOL VarIsConst)
/**************************************************************
INPUT: Two terms with equal top symbols and lexicographic status.
RETURNS: ord_GREATER_THAN if <T1> is greater than <T2>,
ord_EQUAL if both terms are equal and
ord_UNCOMPARABLE otherwise.
CAUTION: If <VarIsConst> is set then variables are interpreted as constants
with lowest precedence. They are ranked to each other using
their variable index.
***************************************************************/
{
ord_RESULT result;
LIST l1, l2, scan1, scan2;
if (symbol_HasProperty(term_TopSymbol(T1), ORDRIGHT)) {
l1 = list_Reverse(term_ArgumentList(T1)); /* Create new lists */
l2 = list_Reverse(term_ArgumentList(T2));
} else {
l1 = term_ArgumentList(T1);
l2 = term_ArgumentList(T2);
}
/* First ignore equal arguments */
result = ord_Equal();
for (scan1 = l1, scan2 = l2; !list_Empty(scan1);
scan1 = list_Cdr(scan1), scan2 = list_Cdr(scan2)) {
result = rpos_GreaterEqual(list_Car(scan1), list_Car(scan2), VarIsConst);
if (!ord_IsEqual(result))
break;
}
if (ord_IsEqual(result)) /* All arguments are equal, so the terms */
/* empty */; /* are equal with respect to RPOS */
else if (ord_IsGreaterThan(result)) {
/* Check if T1 > each remaining argument of T2 */
for (scan2 = list_Cdr(scan2); !list_Empty(scan2) &&
rpos_Greater(T1, list_Car(scan2), VarIsConst);
scan2 = list_Cdr(scan2)); /* Empty body */
if (list_Empty(scan2))
result = ord_GreaterThan();
else
result = ord_Uncomparable();
}
else {
/* Argument of T1 was not >= argument of T2. */
/* Try to find an argument of T1 that is >= T2 */
for (scan1 = list_Cdr(scan1), result = ord_Uncomparable();
!list_Empty(scan1) && !ord_IsGreaterThan(result);
scan1 = list_Cdr(scan1)) {
if (!ord_IsUncomparable(rpos_GreaterEqual(list_Car(scan1), T2, VarIsConst)))
result = ord_GreaterThan();
}
}
if (symbol_HasProperty(term_TopSymbol(T1), ORDRIGHT)) {
list_Delete(l1); /* Delete the lists create above */
list_Delete(l2);
}
return result;
}
static ord_RESULT rpos_ContLexGreaterEqual(CONTEXT C1, TERM T1,
CONTEXT C2, TERM T2)
/**************************************************************
INPUT: Two contexts and two terms with equal top symbols
and lexicographic status.
RETURNS: ord_GREATER_THAN if <T1> is greater than <T2>,
ord_EQUAL if both terms are equal and
ord_UNCOMPARABLE otherwise.
EFFECT: Variable bindings are considered.
***************************************************************/
{
ord_RESULT result;
LIST l1, l2, scan1, scan2;
/* Don't apply bindings at top level, since that happened */
/* in rpos_ContGreaterEqual */
if (symbol_HasProperty(term_TopSymbol(T1), ORDRIGHT)) {
l1 = list_Reverse(term_ArgumentList(T1)); /* Create new lists */
l2 = list_Reverse(term_ArgumentList(T2));
} else {
l1 = term_ArgumentList(T1);
l2 = term_ArgumentList(T2);
}
/* First ignore equal arguments */
result = ord_Equal();
for (scan1 = l1, scan2 = l2; !list_Empty(scan1);
scan1 = list_Cdr(scan1), scan2 = list_Cdr(scan2)) {
result = rpos_ContGreaterEqual(C1, list_Car(scan1), C2, list_Car(scan2));
if (!ord_IsEqual(result))
break;
}
if (ord_IsEqual(result)) /* All arguments are equal, so the terms */
/* empty */; /* are equal with respect to RPOS */
else if (ord_IsGreaterThan(result)) {
/* Check if T1 > each remaining argument of T2 */
for (scan2 = list_Cdr(scan2);
!list_Empty(scan2) && rpos_ContGreater(C1, T1, C2, list_Car(scan2));
scan2 = list_Cdr(scan2)); /* Empty body */
if (list_Empty(scan2))
result = ord_GreaterThan();
else
result = ord_Uncomparable();
}
else {
/* Argument of T1 was not >= argument of T2. */
/* Try to find an argument of T1 that is >= T2 */
for (scan1 = list_Cdr(scan1), result = ord_Uncomparable();
!list_Empty(scan1) && !ord_IsGreaterThan(result);
scan1 = list_Cdr(scan1)) {
if (!ord_IsUncomparable(rpos_ContGreaterEqual(C1,list_Car(scan1),C2,T2)))
result = ord_GreaterThan();
}
}
if (symbol_HasProperty(term_TopSymbol(T1), ORDRIGHT)) {
list_Delete(l1); /* Delete the lists create above */
list_Delete(l2);
}
return result;
}
