class IsLackBracket:
def __init__(self, text_):
self._list = SStack()
self.__text = text_
def is_lack_bracket(self):
i = 0
while True:
while i < len(self.__text):
if self.__text[i] not in ("([{)]}"):
i += 1
break
if self.__text[i] in ("([{"):
self._list.push(self.__text[i])
i += 1
break
if self.__text[i] is ")" and self._list.top() is "(":
self._list.pop()
elif self.__text[i] is "]" and self._list.top() is "[":
self._list.pop()
elif self.__text[i] is "}" and self._list.top() is "{":
self._list.pop()
elif self.__text[i] in (")]}"):
raise SStackError("%s不匹配" % self.__text[i])
i += 1
else:
if self._list.is_empty():
raise SStackError("%s不匹配" % self._list.top())
else:
print("匹配")
def Inf2Suf(line):
st = SStack()
exp = []
for x in tokens(line):
if x not in infix_operators:
exp.append(x)
elif st.is_empty() or x == '(':
st.push(x)
elif x == ')':
while not st.is_empty() and st.top() != '(':
exp.append(st.pop())
if st.is_empty():
raise SyntaxError("Missing '('.")
st.pop()
else:
while (not st.is_empty() and
priority[st.top()] >= priority[x]):
exp.append(st.pop())
st.push(x)
while not st.is_empty():
if st.top() == '(':
raise SyntaxError("Extra '('.")
exp.append(st.pop())
return exp
def trans_infix_suffix(line):
st = SStack()
exp = []
for x in tokens(line):
if x not in infix_operators: # 运算对象直接送出
exp.append(x)
elif st.is_empty() or x == '(': # 左括号进栈
st.push(x)
elif x == ')': # 处理右括号
while not st.is_empty() and st.top() != '(':
exp.append(st.pop())
if st.is_empty(): # 没找到左括号
raise SyntaxError("Missing '('.")
st.pop() # 弹出左括号
else: # 处理算术运算符，运算符都看作左结合
while(not st.is_empty() and
priority[st.top()] >= priority[x]):
exp.append(st.pop())
st.push(x)
while not st.is_empty(): # 送出栈里面剩下的运算符
if st.top() == '(': # 多余的左括号
raise SyntaxError("Extra '('.")
exp.append(st.pop())
return exp
def postorder_nonrec(t, proc):
s = SStack()
while t is not None or not s.is_empty():
while t is not None:
s.push(t)
t = t.left if t.left else t.right
t = s.pop()
proc(t.data)
if not s.is_empty() and s.top().left == t:
t = s.top().right
else:
t = None
def postorder_nonrec(t, proc):
s = SStack()
while t or not s.is_empty():
while t: # 下行循环，直到栈顶的两子树空
s.push(t)
t = t.left if t.left else t.right # 能左就左，否则向右
t = s.pop() # 栈顶是应访问节点
proc(t.data)
if not s.is_empty() and s.top().left == t:
t = s.top().right
else:
t = None