Re: some questions re. Ada/GNAT from a C++/GCC user

[Simon Johnston <skj@ACM.ORG>]

> Bill asked:
>
> The Ada Programming FAQ pooh-poohs STL, but I like it.  (Yes, I know
> I could write my own versions of what I need, but a bunch of Ada
> programmers shouldn't need to be told that that's not the ideal
> solution.)  This FAQ also says the Booch components library is
> coming
>
>   Those opinions do not represent the opinions of all in the Ada
>   community by any means. The STL is a remarkable piece of work in
>   my opinion. There is some very nice work going on at Rensaleer
>   rewriting STL in Ada.

I also like the STL, I also have to use it in C++ development so an
Ada *equivalent* (not necessarily direct port) would be great. I read
a paper recently (can't lay my hand on it now) about implementing the
STL in Ada-95, which although favourable might lead non-Ada people to
believe that an implementation in Ada-95 would be hard, slow,
inefficient and unwieldy. I think such issues should be directly
challanged and lets have an STL-like library ASAP!!

> Does GNAT completely implement generics as defined in the standard?
>
>   Yes
>
> I *assume* that GNAT supports exceptions completely
>
>   You assume correctly
>
> I didn't notice anything about garbage collection in the GNAT docs,
> so I assume it doesn't support it.  Will GNAT support GC in the
> foreseeable future?
>
>   We have no such plans. Several volunteers have mentioned projects
>   to this effect. Perhaps you would like to help in this area!
>
> How well does GDB work with GNAT output?
>
>   Very well. We have used GDB for years to debug GNAT itself, and
>   many of our customers have used it to debug large programs. There
>   are areas where improvements are possible and planned,
>   particularly in the tasking area.
>
>   You assume correctly
>
> I didn't notice anything about garbage collection in the GNAT docs,
> so I assume it doesn't support it.  Will GNAT support GC in the
> foreseeable future?
>
>   We have no such plans. Several volunteers have mentioned projects
>   to this effect. Perhaps you would like to help in this area!
>
> How well does GDB work with GNAT output?
>
>   Very well. We have used GDB for years to debug GNAT itself, and
>   many of our customers have used it to debug large programs. There
>   are areas where improvements are possible and planned,
>   particularly in the tasking area.
>
> Is it possible to get GDB to
> interactively call arbitrary procedures/functions from
> GNAT-generated code?
>
>   Yes.
>
> When I make two different instantiations of a generic package with
> the same arguments, I understand the compiler treats them formally
> as two different packages, which is OK with me.  However, I'd
> appreciate knowing the compiler wouldn't actually output two
> redundant copies of the corresponding (identical?) machine code, but
> instead share the code.
>
>   It is not easy in general to share code. GNAT always generates
>   separate code which results in optimizing time at the expense of
>   space. There are no plans to change this. (Note of course that
>   plans can always be changed by customers with requirements and
>   $$$$)
>
> Can someone give me an idea what kind of compilation speed I could
> expect from GNAT on a 486DX2/66 with 20 Mb of RAM, for projects of
> 1,000-50,000 lines?
>
>   Why not just try it? the cost of a trial copy of GNAT is not
>   expensive! Generally we see compilation speeds of several thousand
>   lines a minute on such machines, but there are many variables.
>
> Robert Dewar
> Ada Core Technologies
>

with StandardDisclaimer; use StandardDisclaimer;
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