calculatrice_aboulin/expression.py

import re

class Token:
    NUMBER = 0
    OPERATOR = 1
    PARENTHESE = 2
    FUNCTION = 3

    @staticmethod
    def isNumber(n):
        return re.match(r'\d+', str(n)) is not None

    @staticmethod
    def getPrecedence(tok):
        if tok == "(" or tok == "":
            return 4
        elif tok == "*" or tok == "/":
            return 3
        elif tok == "+" or tok == "-":
            return 2


    def __init__(self, type, val):
        self.type = type
        self.val = val

class Expression:

    def __init__(self, val=None, gauche=None, droite=None):
        if Token.isNumber(val) and (gauche != None or droite != None):
            raise AttributeError("gauche et droite ne peuvent pas exister si val est un nombre")
        self.val = val
        self.gauche = gauche
        self.droite = droite

    def evalue(self):
        if self.val == "+":
            return self.gauche.evalue() + self.droite.evalue()
        elif self.val == "-":
            return self.gauche.evalue() - self.droite.evalue()
        elif self.val == "*":
            return self.gauche.evalue() * self.droite.evalue()
        elif self.val == "/":
            return self.gauche.evalue() / self.droite.evalue()
        else:
            return float(self.val)

    def __str__(self):
        if Token.isNumber(self.val):
            return str(self.val)
        return "(" + str(self.gauche.__str__()) + str(self.val) + str(self.droite.__str__()) + ")"