提供了评估语言和表达式的方式

使用场景

  1. 解决重复类型的问题，
  2. 通过构建语法树解释语音

Demo

  1. """
  2. 解释器模式
  3. """
  6. class Expression:
  7.     def interpret(self, context):
  8.         raise NotImplementedError()
  11. class TerminalExpression(Expression):
  12.     def __init__(self, data: str):
  13.         self.data = data
  15.     def interpret(self, context: str):
  16.         if context.find(self.data) > -1:
  17.             return True
  18.         return False
  21. class OrExpression(Expression):
  22.     def __init__(self, expr1: Expression, expr2: Expression):
  23.         self.expr1 = expr1
  24.         self.expr2 = expr2
  26.     def interpret(self, context):
  27.         return self.expr1.interpret(context) or self.expr2.interpret(context)
  30. class AndExpression(Expression):
  31.     def __init__(self, expr1: Expression, expr2: Expression):
  32.         self.expr1 = expr1
  33.         self.expr2 = expr2
  35.     def interpret(self, context):
  36.         return self.expr1.interpret(context) and self.expr2.interpret(context)
  39. def get_male_expression():
  40.     r = TerminalExpression('r')
  41.     m = TerminalExpression('m')
  42.     return OrExpression(r, m)
  45. def get_married_woman_expression():
  46.     j = TerminalExpression('j')
  47.     m = TerminalExpression('m')
  48.     return AndExpression(j, m)
  51. if __name__ == '__main__':
  52.     is_male = get_male_expression()
  53.     print("r is male:", is_male.interpret('r'))
  54.     is_married_expression = get_married_woman_expression()
  55.     print(f"ju is a married women:", is_married_expression.interpret('j m'))