def assign_stmt(self):
node = Node(self.values[self.iterator])
#node.set_children(Node(self.values[self.iterator]))
self.match('identifier')
self.match(':=')
node.set_children(self.exp())
return node
def exp(self):
left_node=self.simple_exp()
if self.token=='<' or self.token=='>' or self.token=='=':
op_node=Node(self.values[self.iterator])
self.comparison_op()
op_node.set_children(left_node)
op_node.set_children(self.simple_exp())
left_node = op_node
return left_node
def term(self):
right_node = self.factor()
while self.token=='*' or self.token=='/':
op_node = Node(self.values[self.iterator])
self.mulop()
op_node.set_children(right_node)
right_node = op_node
right_node.set_children(self.factor())
return right_node
def simple_exp(self):
left_node=self.term()
while self.token=='+' or self.token=='-':
op_node = Node(self.values[self.iterator])
self.addop()
op_node.set_children(left_node)
op_node.set_children(self.term())
left_node = op_node
return left_node
def term(self):
right_node = self.factor()
while self.token == '*' or self.token == '/':
op_node = Node(self.values[self.iterator])
self.match(self.token, nonTerminal=True)
op_node.set_children(right_node)
right_node = op_node
right_node.set_children(self.factor())
return right_node
def simple_exp(self):
left_node = self.term()
while self.token == '+' or self.token == '-':
op_node = Node(self.values[self.iterator])
self.match(self.token, nonTerminal=True)
op_node.set_children(left_node)
op_node.set_children(self.term())
left_node = op_node
return left_node
def repeat_stmt(self):
repeat_node=Node(self.values[self.iterator])
if self.token=='repeat':
self.match('repeat')
repeat_node.set_children(self.stmt_sequence())
self.match('until')
#until_node = Node('until')
#until_node.set_children(self.exp())
repeat_node.set_children(self.exp())
return repeat_node
def stmt_sequence(self):
start_node = Node(' ')
start_node.set_children(self.statement())
end_if = self.types[self.iterator-1] == 'end'
while self.token==';' or end_if:
if not end_if:
if not self.match(';'):
break
next_node=self.statement()
if next_node == None:
break
else:
start_node.set_children(next_node)
end_if = self.types[self.iterator-1] == 'end'
return start_node
def if_stmt(self):
if_node=Node(self.values[self.iterator])
if self.token=='if':
self.match('if')
exp_node = Node(' ')
exp_node.set_children(self.exp())
if_node.set_children(exp_node)
self.match('then')
then_node = Node('then')
then_node.set_children(self.stmt_sequence())
if_node.set_children(then_node)
if self.token=='else':
self.match('else')
else_node = Node('else')
else_node.set_children(self.stmt_sequence())
if_node.set_children(else_node)
self.match('end')
return if_node
def write_stmt(self):
node=Node(self.values[self.iterator])
self.match('write')
node.set_children(self.exp())
return node
def read_stmt(self):
node=Node(self.values[self.iterator])
self.match('read')
node.set_children(Node(self.values[self.iterator]))
self.match('identifier')
return node