calc

calc.py

def parse3(l):
    stack = []
    for i in range(len(l)):
        if l[i]=='(':
            stack.insert(0, i)
        elif l[i]==')':
            print l[stack.pop(0):i+1]

def calc(l):
    ll = len(l)
    stack = []
    i = 0
    while(i<ll):
        if l[i]=='(':
            stack.insert(0, i)
        elif l[i]==')':
            b = stack.pop(0)
            e = l[b+1:i].split(' ')
            p = e.pop(0)
            n = int(e.pop(0))
            for j in e:
                n = eval('n'+p+j)
            l = l[:b] + str(n) + l[i+1:]
            i = b

        i+=1
        ll = len(l)

    return int(l)

if __name__=='__main__':

    while 1:
        s = raw_input('-->')
        print calc(s)