Re: scripting/extension language for Ada (we have an opportunity here)

["Samuel T. Harris" <samuel_t_harris@Raytheon.com>]

Robert A Duff wrote:
> 
> "Samuel T. Harris" <samuel_t_harris@Raytheon.com> writes:
> 
> >... So I don't need syntax non-terminals
> > such as function_call_or_array_index_or_qualified_aggregate
> > with all the complexity involved. The semantics
> > still have to verify the appropriate nature of
> > the element.
> >
> > Given this, I believe you would agree that the substitution
> > of () for [] and {} would now be trivial.
> 
> Yes.
> 
> But the simplification of the grammar is fairly minor, when compared
> with the complexity of overload resolution.

I feel the simplification of the grammar is much more than minor.
I get much closer to being able to apply the Ada syntax directly
to aflex/ayacc with these special substitutions. I suppose we
place a different priority on the ease of syntax translation.

However, I do agree with you on the semantics.
They are just as hard with or without special delimiters.

> 
> There may be good and bad things about "[", but I wouldn't say "["
> greatly simplifies the compiler/interpreter, as you've defined it.
> 
> By the way, aggregates (qualified or not) can be syntactically
> distinguished from function calls and whatnot.  The aggregate issue is
> the potential confusion between a parenthesized expression and a
> one-element positional aggregate.  (I consider it a design flaw in Ada
> that there are no one-element and zero-element positional aggregates.
> But with you're "trivial substitution" model, you can't solve that
> problem.)

Yes, that is a stickler with me as well.
All in all, when my short list of Ada peeves contains
these kinds of things, I thinks that speaks very highly
of the quality of the language.

> 
> - Bob

-- 
Samuel T. Harris, Principal Engineer
Raytheon, Aerospace Engineering Services
"If you can make it, We can fake it!"