Re: [RFC] GCC 8 Project proposal: Extensions supporting C Metaprogramming, pseudo-templates

[Daniel Santos <daniel.santos@pobox.com>]

On 05/12/2017 10:49 AM, Martin Sebor wrote:
> On 05/10/2017 04:14 PM, Daniel Santos wrote:
>> Well my primary goal is programming with values that are constant in the
>> compiler.  There is no language in any C specification (that I'm aware
>> of) for a "compile-time constant", but the concept is very important.
>> So just because some expression is a compile-time constant doesn't mean
>> we morph into a "constant expression" (as per the spec), even with
>> __attribute__((const)).
>
> The C committee has discussed extending the set of expressions
> that are considered constant in C2X.  A proposal was submitted
> last year that, at least in spirit, gained pretty broad support
> (the finer details, including the syntax, especially the reuse
> of the register keyword, are likely to evolve):
>
>   http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2067.pdf
>
> The C committee's charter for C2X is to increase compatibility
> with C++, so new language features with that effect have a good
> chance of being considered.
>
> I don't expect C2X to go as far as to add something as complex
> as templates but some on the committee are working on enhancing
> support for generic programming (via _Generic).  Interestingly,
> C11 (by accident) introduced a requirement for implementations
> to support true type genericity in the form of the C11 atomic
> APIs.  It may not be too far out there to propose to generalize
> the underlying machinery and make it available to programs (as
> opposed to just the standard library alone).
>
> Martin

Thank you for this!  It sounds like I need to read up on what is in the 
works with the C committee and maybe prepare my own proposal and become 
involved.  I see the monetary cost of not having generic support as very 
high -- you end up with more boiler-plate code that has to be 
maintained, thus increasing development time and the chance for bugs.  
It also takes more time to analyze the code, diagnose problems and get 
new programmers up to speed.

Thanks,
Daniel