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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: basic questions on using Ada arrays
Date: Sat, 9 Oct 2010 01:35:37 -0500
Organization: Jacob Sparre Andersen
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Date: 2010-10-09T01:35:37-05:00
List-Id: <comp.lang.ada>

"Jacob Sparre Andersen" <sparre@nbi.dk> wrote in message 
news:871v80g2s7.fsf@hugsarin.sparre-andersen.dk...
> Randy Brukardt wrote;
>
>> If you're using an Ada 2005, [...]
>
...
> Wouldn't this implementation of the function be more elegant?
>
>   function Apply (Func : access function (F : Float) return Float;
>                   Arr  : in     Float_Array) return Float_Array is
>   begin
>      return Result : Float_Array (Arr'Range) do
>         Result (I) := Func (Arr (I));
>      end return;
>   end Apply;

It's too elegant: you forgot the for loop! (Thus, there is no declaration 
for I). It should be:

   function Apply (Func : access function (F : Float) return Float;
                   Arr  : in     Float_Array) return Float_Array is
   begin
      return Result : Float_Array (Arr'Range) do
         for I in Arr'Range loop
            Result (I) := Func (Arr (I));
         end loop;
      end return;
   end Apply;

Using the extended return does simplify the code and possibly improves the 
performance as well (by eliminating a copy of the array).

                            Randy.