Python
Number of characters: 382
Yet another Python solution, heavily using regular expression replacement. Each run through the loop the simplest expressions are computed and the results are put back into the string.
This is the unobfuscated code, unless you consider regular expressions to be obfuscated.
import re
from operator import *
operators = dict(zip("+-/*", (add, sub, truediv, mul)))
def compute(s):
def repl(m):
v1, op, v2 = m.groups()
return str(operators[op](float(v1), float(v2)))
while not re.match("^\d+\.\d+$", s):
s = re.sub("([.\d]+)\s*([+-/*])\s*([.\d]+)", repl, s)
s = re.sub("\(([.\d]+)\)", r"\1", s)
return s
Had this idea just as I was turning in and couldn't let it go until I wrote it down and made it work.
