Re: Understanding Booleans

[dewar@gnat.com (Robert Dewar)]

Jeffrey Carter <jeffrey.carter@boeing.com> wrote in message news:<3BFBDF14.4B83708B@boeing.com>...
> Preben Randhol wrote:
> > 
> >       if Get_Active (Object) = True then
> 
> Am I the only one who finds this objectionable? It ends 
> up meaning the
> same thing as
> 
> if Get_Active (Object) then


Absolute rules of style are the hobgoblins ... OK you know
the quote. But it really is appropriate here.

Write whatever is clearer to the reader, and do not think
you can avoid the obligation of figuring out what is clearer by having
absolute rules.

       if At_End_Of_File = True then

seems redundant, indeed, though objectionable seems a 
strong term to use

On the other hand

       if Status_Flags (X) = True then

may be quite clear, depending on the context ...

       if External_Data = True then

would also seem OK to me. 

Where possible choose predicate like names for tests and
then you definitely do not need the "= True".

A related query arises with

   A := (b = c) or (e = f);

some people prefer to write

   if (b = c) or (e = f) then
      A := True;
   else
      A := False;
   end if;

And often people object, but I find that sometimes the
extended form is clearer (boolean values are perfectly
ordinary values from a language point of view, but not
from a normal conceptual point of view, they are rather
special :-)