Re: Do people who use Ada also use ocaml or F#?

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Sat, 30 Oct 2010 03:32:53 +0200, Chad  R. Meiners  
<chad.rmeiners@gmail.com> a écrit:
> let reduce foo =
>   let rec go carry = function
>     | [] -> carry
>     | value :: tail -> go (foo carry value) tail
>   in go
>
> the equivalent Ada would be (don't have an Ada compiler accessible)
>
> generic
>   type t is private;
>   type t_list is limited private;
>   with function foo(Left : t; Right : t) return t;
>   with function head(item : t_list) return t;
>   with function tail(item : t_list) return t_list;
>   with function isNull(item : t_list) return Boolean;
> function reduce(carry : t; list : t_list) return t is
> begin
>   if isNull(list) then
>     return carry;
>   else
>     return reduce(foo(carry, head(list)), tail(list));
>   end if;
> end reduce;

This would not be automatic generalization any more, but depending on the  
objects, tagged types may help here. And if the object type is always the  
same, there is even no need for a generic or a tagged type.

That where ML and Ada differs : the fist required analysis is not the  
same. With ML you do not have to know what will be the type(s) of the  
object, with Ada you must. That is one of the reason why I said ML is  
better at modeling, with Ada, the model is supposed to be known and not to  
be later discovered.

The example, although it is a good one, simply does not apply.

If you want both : model with ML, when the model is stable enough, design  
with Ada (and by the way you may discover and fix some flaws which was not  
visible with the ML view).

> It seems to me others may want to combine the nice traits in each
> language.  I build research algorithms, conciseness is very desirable
> because *I want to be able to fit complete algorithms on a page*
Fitting all on a page, Ada is not made for that. A modeling language is ;)

> I know.  I have used SPARK before, and I have built model checker
> generator in Ada.  I know a little bit about formal methods ;-p
You are experienced so, I am not so much (I just learned and played with  
SPARK).

> I was asking for others' vague and concrete ideas.  It is pretty
> difficult to figure out how ML feature and Ada features can be
> combined.  I am working on a gut feeling that the combination could be
> pretty awesome.  t'class would be pretty nice in an ML language.
Combined together in a whole and large process, from idea to  
implementation and deployment, certainly, but not combined at the language  
level, neither from Ada to ML or the opposite (by the way, I prefer one of  
the originals ML, which seems more pure to me, than OCaml and peers :p ).

> I was asking for others' vague and concrete ideas.
Hope you will get many

Have a nice day and enjoy your research


-- 
Si les chats miaulent et font autant de vocalises bizarres, c’est pas pour  
les chiens.