Re: Improving Ada's image - Was: 7E7 Flight Controls Electronics

["Robert I. Eachus" <rieachus@comcast.net>]

Robert I. Eachus wrote:

> I'll discuss user code first, then tomorrow sum up the other alternatives.

The compiler extension choices seem to rapidly evolve into a much more 
general feature, and one that is needed to support ASIS.  If there is a 
Spelling attribute for enumeration literals, why not support it for all 
variable names?  In fact, why not add it for types as well?  I'm not 
sure I can answer that, but the attribute for enumeration literals 
really needs to be useful in a loop.  You want to convert a value to a 
string, and the fact that it is also the name of an enumeration literal 
that masquerades as a subprogram is a language oddity.

But then again, how many times have you written:

type Color is (Red, Yellow, Green);
C: Color;
...
   Put(C'Image...

and then realized, that no it is Character'Image(C);  Of course, if you 
are using GNAT, you can change it to C'Img,  I guess GNAT could be 
modified to make Img return the original spelling for enumeration 
literals, but I'd much rather have a compiler switch to get that behavior.

Not that big a compiler change.  Will I do it?  No.  I'd rather use the 
methods I posted yesterday and keep the code 'pure' Ada 95 or Ada 05 or 
whatever.

Which leads to language changes.  I'm going to assume that changing 
'Image is a non-starter.  Why?  Well, we might as well implement any 
change the way GNAT implements 'Img, as an attribute of a type or an 
object.  I think if it were to be made a language change, it should be 
'Spelling not 'Img, or maybe there is some other option.

And I guess that is all I have to say on the subject.  It is easy enough 
to implement a 'pure' Ada function Image.  It would also be easy enough 
to add to existing compilers.  If enough people feel strongly that it 
should be done, the compiler vendors will take it from there.

As for me, I guess the only reason I would be in favor of a language 
change would be to get away from Character'Image(C); I think it is ugly, 
and the output you get is ugly too.

-- 

                                           Robert I. Eachus

"Reason and experience both forbid us to expect that national morality 
can prevail in exclusion of religious principles." -- George Washington