Re: private types

[Brian May <bam@snoopy.apana.org.au>]

I am not sure how this:

  function exists return boolean is

    --Later assignment to found_it is evitable
    --
    found_it : boolean := false;

  begin

    if some_precondition then

      found_it := some_other_condition;

    end if;

    return found_it;

  end exists;

Is any better/worse then this:

  function exists return boolean is

    --Later assignment to found_it is evitable
    --
    found_it : boolean;

  begin

    if some_precondition then

      found_it := some_other_condition;

    end if;

    return found_it;

  end exists;

It is possible a smart compiler might trigger a warning in the second
case - but this depends on you noticing the warning and investigating
it. There are cases when the compiler might get confused and produce
false positives or false negatives.

Otherwise, the above problem is a problem that can only be found
either by careful inspection of the code or by proper testing.

For testing the code, as found_it is undefined in the second test, it
is possible it might just fluke the tests you give it and pass
everyone.

The first code is predictable though, and as long as you give it the
same inputs, it will always produce the same outputs, making it easier
(IMHO) to test.
-- 
Brian May <bam@snoopy.apana.org.au>