Fire Method by predefined string!
Mark Lawrence
breamoreboy at yahoo.co.uk
Sun Nov 17 21:29:52 EST 2013
On 18/11/2013 01:41, Steven D'Aprano wrote:
> On Sun, 17 Nov 2013 17:20:52 -0500, Roy Smith wrote:
>
>> In article <mailman.2807.1384725251.18130.python-list at python.org>,
>> Tamer Higazi <th982a at googlemail.com> wrote:
>
>>> I want the param which is a string to be converted, that I can fire
>>> directly a method. Is it somehow possible in python, instead of writing
>>> if else statements ???!
>>
>> I'm not sure why you'd want to do this, but it's certainly possible
>
> It is very good for implementing the Command Dispatch pattern, which in
> turn is very good for building little command interpreters or mini-
> shells. Python even comes with a battery for that:
>
>
> import cmd
> import sys
> class MyShell(cmd.Cmd):
> # Override default behaviour of empty lines.
> def emptyline(self):
> pass
> # Define commands for our shell by prefixing them with "do_".
> def do_hello(self, person):
> if person:
> print("Hello, %s!" % person)
> else:
> print("Hello!")
> def do_echo(self, line):
> print(line)
> def do_double(self, num):
> print(2*float(num))
> def do_bye(self, line):
> return True
>
> MyShell().cmdloop()
>
>
> This defines and runs a command interpreter that understands commands
> "bye", "double", "echo", "hello" and "help". (Help is predefined for you.)
>
> See also http://drunkenpython.org/dispatcher-pattern-safety.html for
> another use of command dispatch.
>
Neat, and yet another Python site to add to my list to keep an eye on,
thanks.
--
Python is the second best programming language in the world.
But the best has yet to be invented. Christian Tismer
Mark Lawrence
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