Calling a string as a function.

[Raymond Hettinger]

brandon.mcginty at gmail.com wrote:
> I'm completely new to python, so sorry for my ignorence.
> How does one go about converting a string, for instants one received through
> tcp, into something that can be called as a function?
> I'm trying to have what the user sends to the computer through the network,
> run as a function.
> If the user sends "motd", the function motd will be run inside the script.

The unsafe way is to run the string through exec or eval():

  s = 'motd()'  # string received from user via the network
    . . .
  exec s

A safer way is to create a limited vocabulary of calls,
look them up in a dictionary and dispatch them to pre-built functions:


  vocab = {'motd': motd, 'quit':quit, 'save':save}
    . . .
  s = 'motd'  # string received from user via the network
    . . . 
  vocab[s]()  # lookup the string and run it if defined