def term(self):
""" term ::= [atom/*factor]
"""
lbranch = self.atom()
t = Operator('')
t.add_branch(lbranch)
# flag == True ==> We don't wrap tree as term. Keep it atom.
flag = True
# onetime == True ==> Every iteration in while() we build new tree, where old tree = left branch of it.
onetime = False
while self.symbol.value in ['/', '*']:
flag = False
tt = t
if onetime:
tt = Operator('')
tt.add_branch(t)
tt.mark = self.symbol.value
if self.symbol.value == '/':
rbranch = self.div()
tt.name = '/'
if self.symbol.value == '*':
rbranch = self.mul()
tt.name = '*'
tt.add_branch(rbranch)
onetime = True
t = tt
if (flag):
t = lbranch
return t
def term(self):
""" term ::= [atom/*factor]
"""
lbranch = self.atom()
t = Operator('')
t.add_branch(lbranch)
# flag == True ==> We don't wrap tree as term. Keep it atom.
flag = True
# onetime == True ==> Every iteration in while() we build new tree, where old tree = left branch of it.
onetime = False
while self.symbol.value in ['/', '*']:
flag = False
tt = t
if onetime:
tt = Operator('')
tt.add_branch(t)
tt.mark = self.symbol.value
if self.symbol.value == '/':
rbranch = self.div()
tt.name = '/'
if self.symbol.value == '*':
rbranch = self.mul()
tt.name = '*'
tt.add_branch(rbranch)
onetime = True
t = tt
if(flag):
t = lbranch
return t
def expression(self):
""" expression ::= [term+-term]
"""
t = Operator('')
sign = 1
# I have no good idea for unary [+/-]
if self.symbol.value == '+':
# ignore this operator
#t.add_branch(Tree(self.symbol))
self.next()
if self.symbol.value == '-':
t.add_branch(Node(self.symbol.value, self.symbol.type))
self.next()
sign = -1
lbranch = self.term()
t.add_branch(lbranch)
flag = True
onetime = False
while self.symbol.value in ['+', '-']:
flag = False
if (onetime):
tt = Operator('')
tt.add_branch(t)
else:
tt = Operator('')
tt.add_branch(lbranch)
symbol = self.symbol
if self.symbol.value == '+':
rbranch = self.add()
tt.name = '+'
if self.symbol.value == '-':
rbranch = self.sub()
tt.name = '-'
tt.mark = symbol.value
tt.add_branch(rbranch)
t = tt
onetime = True
if flag:
t = lbranch
return t
def expression(self):
""" expression ::= [term+-term]
"""
t = Operator( '')
sign = 1
# I have no good idea for unary [+/-]
if self.symbol.value == '+' :
# ignore this operator
#t.add_branch(Tree(self.symbol))
self.next()
if self.symbol.value == '-':
t.add_branch(Node(self.symbol.value, self.symbol.type))
self.next()
sign = -1
lbranch = self.term()
t.add_branch(lbranch)
flag = True
onetime = False
while self.symbol.value in ['+', '-']:
flag = False
if(onetime):
tt = Operator('')
tt.add_branch(t)
else:
tt = Operator('')
tt.add_branch(lbranch)
symbol = self.symbol
if self.symbol.value =='+':
rbranch = self.add()
tt.name = '+'
if self.symbol.value =='-':
rbranch = self.sub()
tt.name = '-'
tt.mark = symbol.value
tt.add_branch(rbranch)
t = tt
onetime = True
if flag:
t = lbranch
return t
