Prompt the user for a value.

prompt.py

import sys
import types
 
castor = {types.IntType:int, types.LongType:long, types.FloatType:float, types.BooleanType:bool}
 
def ask(message, default):
    sys.stdout.write(message + " [" + str(default) + "]:")
    input = sys.stdin.readline().strip()
    
    if input == "":
        return default
    elif type(default) in castor:
        return castor[type(default)](input)
    else:
        return input