Python Four-Function Calculator

var = ['float(']
key = 0

def proc(k):
    elif k == 93:
        return "1"
    elif k == 98:
         return "2"
    elif k == 103:
        return "3"
    elif k == 92:
        return "4"
    elif k == 97:
        return "5"
    elif k == 102:
        return "6"
    elif k == 91:
        return "7"
    elif k == 96:
        return "8"
    elif k == 101:
        return "9"
    elif k == 99:
        return "0"
    elif k == 95:
        return ')/float('
    elif k == 100:
        return ')*float('
    elif k == 105:
        return ')-float('
    elif k == 106:
        return ')+float('
    else:
        return '#'

while key != 108:
    key = input()
    if key == 108:
        break
    elif key != 104:
        key = proc(key)
        if key != '#':
            var.append(key)
        else:
            print 'Invalid entry registered'
    else:
        var.pop()
    print var

var.append(')')
result = ''.join(str(e) for e in var)

print result
print eval(result)