Re: Bad coding standards

[Wayne Magor <none@nowhere.com>]

Ken Garlington wrote:

>
>   function "+" (Left, Right: Some_Type) return Some_Type renames
> Some_Package."+";
>
>   function "-" (Left, Right: Some_Type) return Some_Type renames
> Some_Package."+";
>

This example illustrates why I consider the absolute worst coding standard ever
to have been the common Ada83 standard of "the use of the USE clause is
prohibited".  When you have this ridiculous coding standard, you are almost
forced into doing operator renaming, however, this is very dangerous in Ada.

Do you see the bug in the above code?  The minus operator renames the plus
operator.  If the code is not tested for proper operation through every single
line, it is possible for this to show up in released software (I have seen it).
When you consider the applications for which Ada was designed for (and is being
used in), it is possible that this stupid coding standard could result in
someone's death.

When you consider why is was ever adopted, which was simply to make it easier to
find items declared in other packages, it seems out of proportion to the (albeit
small) risk of catastrophic software failure.  I found 5 of these types of
errors in an avionics application that prohibited the "use" clause in their
coding standards (did not make it on a plane though).  After this, they STILL
did not change the coding standards...

Thank God the "use type" was added to Ada.  Before Ada95, I actually REQUIRED
people to include a "use" clause instead of using operator renaming because of
this very risk.

Wayne.