Re: Ada202X : Adding functors

[Georg Bauhaus <rm.dash-bauhaus@futureapps.de>]

On 15.11.12 08:12, Martin wrote:
> Yup...I think I listed lambdas in another post...possibly even my 'No 1'! No chance of me using them in my C++ work, our compilers aren't up to C++11.
>

If lambda-expressions should help with not naming small
expressions that don't deserve a name (that'll be fun!),
and if lambda-expressions need not be passed upwards,
then maybe more along the lines of if-expressions, and
expression functions,

with Ada.Containers.Vectors;

procedure Foo is
    
    package Nats is new Ada.Containers.Vectors
      (Index_Type => Positive,
       Element_Type => Natural);

    V : Nats.Vector;
    Sum : Natural := 0;

begin  -- not Ada

    V.Iterate (Process => (with (Position : Cursor) do
                             Sum := Sum + Element (Position)));

    declare
       Copy2 : Nats.Vector;
    begin
       for E of V loop
          Copy2.Append
            (New_Item =>
               (with (X : Natural => E) return Natural is
                  2 * X));
       end loop;
    end;

end Foo;