用python代码写模拟计算器的程序

import re
# 计算乘除
def cheng_chu(cc):
    cc_ret = cc
    while 1:
        ret1 = re.search('([\d\.]+)(\*|\/)(-?[\d\.]+)', cc_ret)
        if ret1:
            if ret1.group(2) == '*':
                s = float(ret1.group(1)) * float(ret1.group(3))
                cc_ret = cc_ret.replace(ret1.group(), str(s))
            elif ret1.group(2) == '/':
                s = float(ret1.group(1)) / float(ret1.group(3))
                cc_ret = cc_ret.replace(ret1.group(), str(s))
        else:
            break
    return cc_ret
# 计算加减
def jia_jian(jj):
    jj_ret = jj.replace('+-' or '-+', '-')
    jj_ret = jj_ret.replace('--', '+')
    s = 0
    ret1 = re.findall('\-([\d\.]+)', jj_ret)
    for n in ret1:
        s -= float(n)
    ret2 = re.findall('\+([\d\.]+)', jj_ret)
    for n in ret2:
        s += float(n)
    ret3 = re.findall('\(([\d\.]+)', jj_ret)
    for n in ret3:
        s += float(n)
    ret4 = re.findall('^([\d\.]+)', jj_ret)
    for n in ret4:
        s += float(n)
    return str(s)

exp = '1-2*((60-30+(-40/5)*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))'
exp2 = exp
while True:
    ret = re.findall('\(([^()]+)\)', exp2)  # 1.匹配小括号中的内容
    if ret:
        for i in ret:
            step2 = cheng_chu(i)  # 计算出括号内乘除法的结果
            step3 = jia_jian(f'({step2})')  # 计算出括号内加减法的结果
            exp2 = exp2.replace(f'({i})', step3)
    else:
        break
print(jia_jian(cheng_chu(exp2)))