Re: AQ&S Guidance on pragma Elaborate_Body

[bobduff@world.std.com (Robert A Duff)]

In article <mheaney-ya023680002404970055380001@news.ni.net>,
Matthew Heaney <mheaney@ni.net> wrote:
>What should the instantiator do if the generic has a pragma Pure, Preelab,
>or Elab_Body?  Does the instantiator still have to pragma Elaborate_All the
>generic package?  Or can he omit that pragma?

Elab_All can be omitted in this case, which is one reason why Pure,
Preelab, and Elab_Body are so convenient.  (Robert has pointed out how
to put debugging statements in Pure units -- if you're not using GNAT,
you can cheat in a similar way by calling some pragma-Imported thing --
which I suppose could be written in Ada.)

>Can you explain when exactly does the pragma Pure of the generic package
>apply?  During elaboration of the generic, or of the instantiation?

The generic.  If you want the instance to be pure, you have to put the
pragma on the instance (if its a lib unit), or on the containing lib
unit.  This last is not obvious from the RM -- there's an AI on this
issue.

- Bob