Re: S-expression I/O in Ada

[Georg Bauhaus <rm-host.bauhaus@maps.futureapps.de>]

On 8/29/10 12:45 PM, Natasha Kerensikova wrote:

> So I guess that would be "-gnatwae -gnaty" (I do like the idea of style
> checks too). But this raises the question, what is the rationale for
> excluding some warning from -gnatwa?

A programmer might know more than he or she can express  as an
instruction to a compiler, and still be portable among compilers.
Example:

overriding
procedure P (Item : in out Some_Type; Unused : Another_Type) is
   ...

Full warnings might list a message about "Unused" being unused.
You might not want to see it all the time. One possible reason is
that the parameter will not be used, since the algorithm does
not need it. I think that there is a GNAT specific pragma to
suppress the warning (which possibly is reflected somewhere in
the sequence of letters following -gnatw...).

On the other hand, other ways to deliberately ignore a warning are
possible, more portable, and less error prone than the pragma, IMHO.
For just as well, if the procedure P is currently being worked
on, parameter Unused might become used, and then the additional pragma
needs to be dealt with instead.  Other compilers might warn about a
pragma they don't recognize and will ignore. This defeats the purpose.



Georg