function with a lot of parameters --maintainability issue

[William Park]

On Tue, Oct 31, 2000 at 07:16:26PM +0000, etsang at my-deja.com wrote:
> Hi all,
> 
> I have several functions that takes in more than 255 parameters and
> cause Python to complain about com_addbyte error out of range.
> We are using Python 1.5.2 and have to take that versiona t the moment.
> 
> I think one way to get around that is as follows:
> 
> Since a lot of your functions are like:
> def func(sid,a,b,c,d,e,f, ..... more than 255 parameters):
> 
>     setVariable(sid,.....,a);
>     setVariable(sid,.....,b);
>     .....
>     setVariable(sid,.....,z);
>     ......
>     sendPrim(sid,"somePrim ..");
> we can break the function into several functions:
> 
> def func1(sid,a,b,c,d,e):
>     setVariable(sid,.....,a);
>     setVariable(sid,.....,b);
>     ....
>     setVariable(sid,.....,d);
>     setVariable(sid,.....,e);
> def func2(sid,f,g,h,i,....):
>     setVariable(sid,.....,f);
>     setVariable(sid,.....,g);
>     ....
> 
> def func3(sid,......):
>     setVariable(sid, ....);
>     sendPrim(sid,........);
> Note that setVariable and sendPrim are just other user defined
> functions.
> 
> Then just call these three functions in order of func1,func2,func3.
> 
> That is in places that call func, that following is replaced
> func1, func2, func3. There are quite a lot of places that call func.
> So this may generate maintainability issue, as we need to keep track of
> three functions instead of one.
> 
> So can anyone suggest a better solution at the moment?

Yes, pass dictionary to the function, ie.

    def func(sid, args):
	for i in args.keys():
	    setVariable(sid, ..., args[i])	# argv['a'], ...

    argv = {'a':..., 'b':..., 'c':..., ...}
    func(sid, argv)

---William Park, Open Geometry Consulting