RE: [ESPResSo-devel] TCL procedures with variable calling parameters

[Limbach, Hans Joerg, LAUSANNE, NRC-FS]

Thanks Olaf!

So indeed that might be more clear, but it is also quite lengthy! But
probably one can pack this in a function that handles optional arguments
like
handle_opt_args "p1 p2 p3 p4" "d1 d2 d3 d4" $args  
(I guess that can be done using upvar or something similar), that one
then can call at the beginning of a procedure. Of course the additional
features of Olafs suggestion should also be possible.

And don't be afraid. I do not plan to change all interfaces in Espresso,
but I would like to add some stuff where this would be handy, and I
would like to agree on a way how to implement such a feature in a
defined way. Otherwise we end up with as many procedure interfaces as we
have programmers.

Greetings,
Hanjo

> -----Original Message-----
> From: Olaf Lenz [mailto:address@hidden 
> Sent: vendredi, 26. octobre 2007 14:24
> To: Limbach,Hans Joerg,LAUSANNE,NRC-FS
> Cc: address@hidden
> Subject: Re: [ESPResSo-devel] TCL procedures with variable 
> calling parameters
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Hi!
> 
> Limbach, Hans Joerg, LAUSANNE, NRC-FS wrote:
> > I find it often very anoying that you one always has to 
> look for the 
> > right order of arguments and in addition that you have to 
> give all of 
> > them all the time.
> 
> Indeed, this is annoying. In general, whenever a Tcl proc has 
> optional arguments, a comparable construct is required.
> 
> Attached, you'll find a modified version of Hanjos script 
> demonstarting the technique that I have been using in the 
> pbctools plugin for VMD and also in ESPResSo in 
> scripts/vtf.tcl (e.g. for the proc writevcf).
> 
> It basically does the same as Hanjos script, but has a number 
> of additional features:
> 1. It is more readable (I think).
> 2. It can handle optional arguments with no arguments 
> ("switches") or with more than one argument.
> 3. It passes through the mandatory arguments, i.e. after the 
> option processing, $args contains the remaining arguments 
> that can be handled classically.
> 
> Although this is not necessary, I have changed the optional 
> arguments to require a "-" in front of it, as is common e.g. 
> in Unix commands. This makes it easier to read the proc call, 
> as one can distinguish between the optional arguments and the 
> mandatory arguments.
> 
> > Have a look at it and let me know what you think.
> > I am almost sure that this either might exist already or 
> that somebody 
> > of you has a better idea how to handle this. In my opinion 
> something 
> > like this would make Espresso much more user friendly.
> 
> You are absolutely right. However, this would require to 
> change the UI of most of ESPResSos functions and would render 
> all already written scripts invalid! Therefore I think doing 
> this change would be something for ES++.
> 
> In general, this shows, how important it is to think 
> thoroughly about the UI that you give to a new function, 
> because it is very hard to change it afterwards, when it is 
> already used by many people.
> 
> Olaf
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.1 (GNU/Linux)
> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
> 
> iD8DBQFHIdxGtQ3riQ3oo/oRAlwIAJ4lfefzkr/C1/m3KJn3DL8aicdMpACgoYle
> mc5gMmAZ0QBpVie9LLW1mss=
> =KTPG
> -----END PGP SIGNATURE-----
>