Calling a string as a function.

[Guest]

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.
Thanks Much,
Brandon McGinty
Brandon.mcginty @gmail.com

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[Grant Edwards]

Re: Calling a string as a function.

On 2006-02-03, <brandon.mcgint y@gmail.com> <brandon.mcgint y@gmail.com> wrote:
[color=blue]
> How does one go about converting a string, for instants one received through
> tcp, into something that can be called as a function?[/color]

http://groups.google.com/group/comp.lang.python/browse_thread/thread/6735f7e30fffb077

[Raymond Hettinger]

Re: Calling a string as a function.

brandon.mcginty @gmail.com wrote:[color=blue]
> 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.[/color]

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