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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: Initializing an array of tasks with discrimants
Date: Fri, 22 Nov 2019 23:39:53 +0100
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Date: 2019-11-22T23:39:53+01:00
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On 11/22/19 11:07 PM, Jere wrote:
> I recently ran into a situation where I had an array
> of tasks that had discriminants (with a default), but
> I couldn't find a simple way to initialize them.  I
> did come up with a workaround, but wanted to see if
> the language defined a way to do this:

The standard way to do this is for the default to be a function call:

Next_Value : Positive := 1;

function Next return Positive is
    Result : constant Positive := Next_Value;
begin -- Next
    Next_Value := Next_Value + 1;

    return Result;
end Next;

task type T (D : Positive := Next);

type T_List is array (Positive range <>) of T;

A : T_List (1 .. Num_Tasks);

The language guarantees that the calls to Next will occur sequentially. The 
order of the calls is not defined, so there is no guarantee that the index and 
discriminant of a T in A will be the same.

-- 
Jeff Carter
"I would never want to belong to any club that
would have someone like me for a member."
Annie Hall
41