Re: [boost] Review Request: Variadic Macro Data library

Subject: Re: [boost] Review Request: Variadic Macro Data library
From: Paul Mensonides (pmenso57_at_[hidden])
Date: 2011-02-20 10:43:52

On Sun, 20 Feb 2011 09:55:14 -0500, Daniel Larimer wrote:

> I think that you have identified a very good use for the variadic
> argument, but I am not sure that it completely conflicts with the ideas
> present in the VMD library.  So unless providing utilities to convert
> from VA_ARGS -> SEQ, LIST, Array, etc somehow prevents you from
> expanding the FOR_EACH macro like you described, I would tend to favor
> an incremental approach.  Don't hold up useful functionality because
> there is more useful functionality you could add.
>
> Reworking the whole of the PP library with VA support sounds like it
> would significantly delay the adoption of some very useful tools.

I don't have a problem with the particular macros.  I do have a concern 
about establishing practices which I don't consider to be terribly good 
practices.

I'd really like to see a use case that is different from what I'm 
envisioning.  What I'm envisioning is something like:

#define ALGORITHM_B(...) \
    ALGORITHM_A(DATA_TO_SEQ(__VA_ARGS__)) \
    /**/

ALGORITHM_B(a, b, c)

I don't find that use case compelling, and that point of view is based on 
heavy experience utilizing variadics.  When I was initially writing chaos-
pp, I went down this path, but ultimately rejected it.  It simply doesn't 
scale and results in other intrastructure that doesn't scale.

To attempt to clarify, something like

ALGORITHM_A(DATA_TO_SEQ(a, b, c))

is not really a problem, but the existence of the ALGORITHM_B definition 
(as a non-local construct) *is* a problem.

Regards,
Paul Mensonides