ord_RESULT rpos_ContGreaterEqual(CONTEXT C1, TERM T1, CONTEXT C2, TERM T2)
/**************************************************************
INPUT: Two contexts and two terms.
RETURNS: ord_GREATER_THAN if <T1> is greater than <T2>
ord_EQUAL if both terms are equal
ord_UNCOMPARABLE otherwise.
EFFECT: Variable bindings are considered.
CAUTION: The precedence from the order module is used to determine
the precedence of symbols!
***************************************************************/
{
LIST scan;
T1 = cont_Deref(&C1, T1);
T2 = cont_Deref(&C2, T2);
if (term_IsVariable(T1)) {
if (term_EqualTopSymbols(T1, T2))
return ord_Equal(); /* T2 is the same variable */
else
/* A variable can't be greater than another term */
return ord_Uncomparable();
} else if (term_IsVariable(T2)) { /* T1 isn't a variable */
if (cont_TermContainsSymbol(C1, T1, term_TopSymbol(T2)))
return ord_GreaterThan();
else
return ord_Uncomparable();
} else if (term_EqualTopSymbols(T1, T2)) {
if (symbol_HasProperty(term_TopSymbol(T1), ORDMUL))
return rpos_ContMulGreaterEqual(C1, T1, C2, T2);
else
return rpos_ContLexGreaterEqual(C1, T1, C2, T2);
} else {
if (symbol_PrecedenceGreater(ord_PRECEDENCE, term_TopSymbol(T1),
term_TopSymbol(T2))) {
/* Different top symbols, symbol of T1 > symbol of T2. */
/* Try if T1 > each argument of T2. */
for (scan = term_ArgumentList(T2); !list_Empty(scan); scan = list_Cdr(scan))
if (!rpos_ContGreater(C1, T1, C2, list_Car(scan)))
return ord_Uncomparable();
return ord_GreaterThan();
} else {
/* Try to find an argument of T1 that is >= T2 */
for (scan = term_ArgumentList(T1); !list_Empty(scan); scan = list_Cdr(scan))
if (!ord_IsUncomparable(rpos_ContGreaterEqual(C1,list_Car(scan),C2,T2)))
return ord_GreaterThan(); /* Argument of T1 >= T2 */
return ord_Uncomparable();
}
}
}
ord_RESULT rpos_ContGreaterEqual(CONTEXT GlobalC1, CONTEXT TermC1, TERM T1,
CONTEXT GlobalC2, CONTEXT TermC2, TERM T2,
BOOL VarIsConst)
/**************************************************************
INPUT: Two contexts and two terms.
RETURNS: ord_GREATER_THAN if <T1> is greater than <T2>
ord_EQUAL if both terms are equal
ord_UNCOMPARABLE otherwise.
EFFECT: Variable bindings are considered.
CAUTION: The precedence from the order module is used to determine
the precedence of symbols!
If <VarIsConst> is set then variables are interpreted as constants
with lowest precedence. They are ranked to each other using
their variable index.
ASSUMPTION: All index variables of <T1> and <T2> are bound in
<GlobalC1> and <GlobalCt2>, respectively
***************************************************************/
{
LIST scan;
T1 = cont_Deref(GlobalC1, &TermC1, T1);
T2 = cont_Deref(GlobalC2, &TermC2, T2);
if (term_IsVariable(T1)) {
if (term_EqualTopSymbols(T1, T2))
return ord_Equal(); /* T2 is the same variable */
else
/* A variable can't be greater than another term */
return ord_Uncomparable();
} else if (term_IsVariable(T2)) { /* T1 isn't a variable */
if (cont_TermContainsSymbol(GlobalC1, TermC1, T1, term_TopSymbol(T2)))
return ord_GreaterThan();
else
return ord_Uncomparable();
} else if (term_EqualTopSymbols(T1, T2)) {
if (symbol_HasProperty(term_TopSymbol(T1), ORDMUL))
return rpos_ContMulGreaterEqual(GlobalC1, TermC1, T1,
GlobalC2, TermC2, T2, VarIsConst);
else
return rpos_ContLexGreaterEqual(GlobalC1, TermC1, T1,
GlobalC2, TermC2, T2, VarIsConst);
} else {
if (symbol_PrecedenceGreater(ord_PRECEDENCE, term_TopSymbol(T1),
term_TopSymbol(T2))) {
/* Different top symbols, symbol of T1 > symbol of T2. */
/* Try if T1 > each argument of T2. */
for (scan = term_ArgumentList(T2); !list_Empty(scan); scan = list_Cdr(scan))
if (!rpos_ContGreaterAux(GlobalC1, TermC1, T1,
GlobalC2, TermC2, list_Car(scan), VarIsConst))
return ord_Uncomparable();
return ord_GreaterThan();
} else {
/* Try to find an argument of T1 that is >= T2 */
for (scan = term_ArgumentList(T1); !list_Empty(scan); scan = list_Cdr(scan))
if (!ord_IsUncomparable(rpos_ContGreaterEqual(GlobalC1, TermC1,list_Car(scan),
GlobalC2, TermC2,T2,
VarIsConst)))
return ord_GreaterThan(); /* Argument of T1 >= T2 */
return ord_Uncomparable();
}
}
}