import pygtk
pygtk.require('2.0')
import gtk

from math import sqrt
from operator import add,sub,mul,div,pow

import util

opfns = {
    '+' : add,
    '-' : sub,
    '*' : mul,
    '/' : div,
    '**' : pow,
    'sqrt' : sqrt
    }

def handle_operation (entry, label):
    ops = entry.props.text.split ()
    try:
        operador  = ops [0] 
        operandos = ops [1:]
        funcion = opfns [operador]
        res = funcion (* map (float, operandos))
        label.props.label = " = " + str (res)
    except (KeyError, IndexError, ValueError, TypeError):
        util.show_error_dialog ("Error", "Orden incorrecta")

def calculadora ():
    win = gtk.Window ()
    win.connect ('destroy', gtk.main_quit)
    win.props.title = "Super calculadora!"
    
    
    box = gtk.VBox (False, 0)
    win.add (box)

    label = gtk.Label (" = 0")
    entry = gtk.Entry ()
    entry.connect ("activate", handle_operation, label)
    
    box.pack_start (entry)
    box.pack_start (label)

    opfns ["exit"] = win.destroy
    
    win.show_all ()
    gtk.main ()


if __name__ == '__main__':
    calculadora ()