def expression():
"""
Parses
expression = simpleExpression
{("=" | "<>" | "<" | "<=" | ">" | ">=") simpleExpression}.
Generates code for the expression if no error is reported
"""
x = simpleExpression()
while SC.sym in {EQ, NE, LT, LE, GT, GE}:
op = SC.sym; getSym(); y = simpleExpression() # x op y
if x.tp == Int == y.tp:
#============== ADDED CONSTANT FOLDING =============
if type(x) == Const == type(y): #
if op == EQ and x.val != y.val: #
x = genSkip() #
elif op == NE and x.val == y.val: #
x = genSkip() #
elif op == LT and x.val >= y.val: #
x = genSkip() #
elif op == LE and x.val > y.val: #
x = genSkip() #
elif op == GT and x.val <= y.val: #
x = genSkip() #
elif op == GE and x.val < y.val: #
x = genSkip() #
else:
x = genRelation(op, x, y)
else: mark('bad type')
def expression():
"""
Parses
expression = simpleExpression
{("=" | "<>" | "<" | "<=" | ">" | ">=") simpleExpression}.
Generates code for the expression if no error is reported
"""
x = simpleExpression()
while SC.sym in {EQ, NE, LT, LE, GT, GE}:
op = SC.sym
getSym()
y = simpleExpression() # x op y
if x.tp == Int == y.tp:
x = genRelation(op, x, y)
else:
mark("bad type")
return x