Re: Overriding discriminants perplexes GNAT 3.14p

[tmoran@acm.org]

> Why do you need more than one compiler?
  Perhaps the answer lies in another c.l.a. thread "Subject: Re: SofTech
Ada 86 Compiler":
>>I'm looking for a copy of the SofTech Ada 86 compiler, that is, their
>>compiler for the Intel 80x86 platform. Yes, I know that the compiler is no
>>longer support, and that any code developed with this compiler should be
>>moved to a more current platform. But we need to do some maintenance work on
>>a program developed with this compiler, and do it quickly. Any help you

Running code through more than one compiler is helpful in finding
non-portabilities, and sometimes one compiler will issue warnings about
your use of some construct, where another compiler is silent.

Programs supplied in source form must be able to compile on the compiler
the user has.  Claw, for instance, does not insist on anybody's specific
compiler, but compiles under the normal public versions of Apex, Gnat,
Janus, and ObjectAda.  There are a few things unspecified by Ada where we
have to supply different packages for the different compilers, and
sometimes one compiler will have a bug that needs a special workaround.
Since Claw targets the compilers users have, and not specially patched
versions some users can get, bug workarounds have to stay, typically for a
year or so, until the next corrected public release of a compiler.  Given
these circumstances, I think there is remarkably little special pieces of
code catering to specific compilers.