This repo contains code to mirror other repos. It also contains the code that is getting mirrored.
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1.2 KiB

  1. from lark import Lark, InlineTransformer
  2. calc_grammar = """
  3. ?start: sum
  4. | NAME "=" sum -> assign_var
  5. ?sum: product
  6. | sum "+" product -> add
  7. | sum "-" product -> sub
  8. ?product: atom
  9. | product "*" atom -> mul
  10. | product "/" atom -> div
  11. ?atom: /[\d.]+/ -> number
  12. | "-" atom -> neg
  13. | NAME -> var
  14. | "(" sum ")"
  15. NAME: /[a-zA-Z]\w*/
  16. WS.ignore: /\s+/
  17. """
  18. class CalculateTree(InlineTransformer):
  19. from operator import add, sub, mul, truediv as div, neg
  20. number = float
  21. def __init__(self):
  22. self.vars = {}
  23. def assign_var(self, name, value):
  24. self.vars[name] = value
  25. return value
  26. def var(self, name):
  27. return self.vars[name]
  28. calc_parser = Lark(calc_grammar, parser='lalr', transformer=CalculateTree())
  29. calc = calc_parser.parse
  30. def main():
  31. while True:
  32. try:
  33. s = raw_input('> ')
  34. except EOFError:
  35. break
  36. print(calc(s))
  37. def test():
  38. # print calc("a=(1+2)")
  39. print(calc("a = 1+2"))
  40. print(calc("1+a*-3"))
  41. if __name__ == '__main__':
  42. test()
  43. # main()