class ReversePolishNotationConverterState:
"""
Class to store the state of RPN convert process
"""
def __init__(self, expression_in_infix_notation: str):
"""
:param expression_in_infix_notation: string with expression in infix notation
"""
self.expression_in_infix_notation = Queue_(
expression_in_infix_notation)
self.expression_in_postfix_notation = ReversePolishNotation()
self.stack = Stack()
def pop_from_stack_until_opening_bracket(self):
"""
Help function помогает вытащить все из стека
:return:
"""
el = self.stack.top()
while not isinstance(el, OpenBracket):
self.expression_in_postfix_notation.put(el)
self.stack.top()
# выкнуть откр скобку из стека
self.stack.pop()
def infix_to_postfix(expression):
postfix = []
priority = {'(': 1, '&': 2, '|': 2, '!': 2}
operators = Stack()
for token in expression:
if token in OPERATORS:
# Operators are added to the stack, but first the ones with a
# higher priority are added to the result:
while not operators.is_empty() and priority[token] <= priority[
operators.top()]:
postfix.append(operators.pop())
operators.push(token)
# Left parenthesis are added to the stack:
elif token == '(':
operators.push(token)
# Operators between parenthesis are added from the stack to the result:
elif token == ')':
while operators.top() != '(':
postfix.append(operators.pop())
operators.pop() # Pop the left parentheses from the stack.
# Operands are added to the result:
else:
postfix.append(token)
while not operators.is_empty():
# The remaining operators are added from the stack to the result:
postfix.append(operators.pop())
return postfix
class ReversePolishNotationConverterState:
"""
Class to store the state of RPN convert process
"""
def __init__(self, expression_in_infix_notation: str):
self.expression_in_infix_notation = Queue_(expression_in_infix_notation)
self.expression_in_postfix_notation = ReversePolishNotation()
self.stack = Stack()
while not ReversePolishNotationConverter.is_open_bracket(self.stack.top()):
self.expression_in_postfix_notation.put(self.stack.top())
self.stack.pop()
self.stack.pop()
def testStack(self):
stack = Stack()
self.assertTrue(stack.isEmpty())
stack.push(5)
self.assertFalse(stack.isEmpty())
stack.clear()
self.assertTrue(stack.isEmpty())
stack.push(6)
self.assertEqual(6, stack.top())
self.assertEqual(6, stack.pop())
self.assertTrue(stack.isEmpty())
stack.push(7)
stack.push(6)
stack.push(5)
self.assertEqual(5, stack.pop())
self.assertEqual(6, stack.pop())
self.assertEqual(7, stack.top())
def testStack(self):
stack = Stack()
self.assertTrue(stack.isEmpty())
stack.push(5)
self.assertFalse(stack.isEmpty())
stack.clear()
self.assertTrue(stack.isEmpty())
stack.push(6)
self.assertEqual(6, stack.top())
self.assertEqual(6, stack.pop())
self.assertTrue(stack.isEmpty())
stack.push(7)
stack.push(6)
stack.push(5)
self.assertEqual(5, stack.pop())
self.assertEqual(6, stack.pop())
self.assertEqual(7, stack.top())
class ReversePolishNotationConverterState:
"""
Class to store the state of RPN convert process
"""
def __init__(self, expression_in_infix_notation: str):
"""
:param expression_in_infix_notation: string with expression in infix notation
"""
self.expression_in_infix_notation = Queue_(
expression_in_infix_notation)
self.expression_in_postfix_notation = ReversePolishNotation()
self.stack = Stack()
def pop_from_stack_until_opening_bracket(self):
"""
Help function
:return:
"""
while not ReversePolishNotationConverter.is_open_bracket(
self.stack.top()):
self.expression_in_postfix_notation.put(self.stack.top())
self.stack.pop()
self.stack.pop()
class ReversePolishNotationConverter:
def __init__(self, infix_string: str):
self._infix_notation = Queue_(infix_string)
self._postfix_notation = ReversePolishNotation()
self.stack = Stack()
point = '.'
def convert(self, expression_in_infix_notation: str) -> ReversePolishNotation:
while not self._infix_notation.empty():
character = self._infix_notation.get()
if self.is_part_of_digit(character):
digit = self.read_digit(character)
self._postfix_notation.put(digit)
continue
elif self.is_opening_bracket(character):
self.stack.push(character)
continue
elif self.is_closing_bracket(character):
self.pop_from_stack_until_opening_bracket()
continue
operator = OpFactory.get_op_by_symbol(character)
if self.is_binary_operation(operator):
self.pop_from_stack_until_prioritizing(operator)
else:
raise Exception(character)
while not self.stack.empty():
self._postfix_notation.put(self.stack.top())
self.stack.pop()
return self._postfix_notation
def pop_from_stack_until_opening_bracket(self):
while not self.is_opening_bracket(self.stack.top()):
self._postfix_notation.put_operator(self.stack.top())
self.stack.pop()
self.stack.pop()
def pop_from_stack_until_prioritizing(self, operator: Op, state: ReversePolishNotationConverterState):
current_priority = operator.priority
while not self.stack.empty() and self.stack.top().priority > current_priority:
self._postfix_notation.put(self.stack.top())
self.stack.pop()
self.stack.push(operator)
def read_digit(self, character: str) -> Digit:
digit = character
while not self._infix_notation.empty() and self.is_part_of_digit(self._infix_notation.top()):
digit += self._infix_notation.get()
return Digit(digit)
@staticmethod
def is_part_of_digit(character: str) -> bool:
return character.isdigit() or character == ReversePolishNotationConverter.point
@staticmethod
def is_open_bracket(character: str, operator: Op) -> bool:
if character == '(':
return True
return False
@staticmethod
def is_close_bracket(character: str, operator: Op) -> bool:
if character == ')':
return True
return False
@staticmethod
def is_binary_operation(operator: Op) -> bool:
return isinstance(operator, BinaryOp)
