Re: Selective suppression of warnings --- gnat on GNU/Linux

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

On Dec 30, 4:13 am, Michael Mounteney <gat...@landcroft.co.uk> wrote:
> Hello, I am trying to build an application of which some of the source
> is automatically translated from Pascal, on the fly.  The problem is
> that the automatically-translated source is causing a lot of spurious
> warnings about declarations not being used.  This is because the
> Pascal code has many instances of:
>
>      type
>           somerange = 1..10;
>           somestruct = record ... end;
>
> which is translated into Ada as
>
>      type somerange is new integer range 1 .. 10;
>
>      type somestruct is record ... end record;
>
> but the problem is that any operators such as + and = are not visible
> in other units.  The solution to that is to rename the operators in
> the client units, thus:
>
>      with stage3;    -- contains definitions of somerange, somestruct
> etc.
>
>      package body myusage is
>
>           function "=" (L, R : in stage3.somestruct) return Boolean
> renames stage3."=";
>           function "+" (L, R : in stage3.somerange) return
> stage3.somerange renames stage3."+";
>           ..........
>      end myusage;
>
> without those renamings, any usage of = and + within the body of
> myusage are flagged as errors owing to lack of visibility/
> qualification.
>
> The translator is a rather crude line-by-line affair written in
> Haskell that only performs partial analysis of the source, and
> certainly isn't up to identifying the arguments to operators within
> expressions.  Thus, it produces the renaming clauses if it encounters
> the type name is the source;  e.g., if it sees somerange, it outputs
> all the renamings for somerange.  However, the renamings usually are
> not required, so gnat warns about them.  Normally, this would not be a
> problem;  one would simply remove the unneeded declaration from the
> source.  I did try putting the declarations into another package and
> then "with" and "use" that, but then the warning changes to "no
> declarations used from the package".
>
> I really really really don't like "use" anyway and prefer always to
> qualify imported names.
>
> What I'd like is a pragma that switches-off and switches-on the
> warning over the specific range of lines containing the renamings, but
> no such seems to be available.  I don't want to switch off the warning
> from the command line as that will suppress valid warnings.
>
> Is there another way ?  Is there some rearrangement of the source that
> WOULD suppress the unwanted warnings.
>
> So the question:

Have you tried replacing the renaming declarations with "use type
somerange;" ? One such clause applies to all operators. You will get
fewer warnings, as if a single operator is used then the "use type"
clause does not cause a warning.

--
Ludovic Brenta.