nice features in Ada 2012, expressions

nice features in Ada 2012, expressions

[Nasser M. Abbasi]

I was looking at Ada 2012 expressions

http://www.adacore.com/uploads/technical-papers/Ada2012_Rationale_Chp2_expressions.pdf

and I really like what I see. Ada is becoming more expressive now,
with less code, which I think is a good thing(TM).

It is getting almost as short as Matlab now (but with the strong
type build-in)

Given a matrix A, and I want to find if all elements in
the matrix are say positive, then in Matlab I would write

--------------------
B = all(A(:)>0)

In ada 2012 it is

B := (for all e of A => e>0);
--------------------

and if I want to find if there is at least one
value > 0 then in Matlab I would write

----------------------
B = any(A(:)>0)

and in Ada 2012

B := (for some e of A => e>0);
-----------------------

I think this is nice.

I am not sure yet, since I do not know much about Ada 2012,
if I can use this new iterator form if A was a standard array
variable, or if it will work only if A was a 'container' variable?

i.e. if A above was just variable of type like

        'A_type is array(integer) of float'

I hope it will work on standard arrays and not just on
collections so I can use it this form more.

I think these are the type of improvements needed in Ada to
make it more popular and more used. Real practical and
useful things.

I am looking forward for the 2012 gnat to try it out.

--Nasser

Re: nice features in Ada 2012, expressions

[Pascal Obry]

Nasser,

> I am not sure yet, since I do not know much about Ada 2012,
> if I can use this new iterator form if A was a standard array
> variable, or if it will work only if A was a 'container' variable?

It works fine with standard arrays.

Pascal.

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