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From: Lutz Donnerhacke <lutz@iks-jena.de>
Newsgroups: comp.lang.ada
Subject: Re: Keyword "null" Question
Date: Fri, 17 Jan 2003 15:10:10 +0000 (UTC)
Organization: IKS GmbH Jena
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* Michael Bustillo wrote:
>     if SOME_EVENT_TOOK_PLACE then
>         null;
>     end if;
>
> This statement is simply standing alone by itself, not part of any
> "case-like" structure or anything sneaky.  I guess my question is when
> it says "...it does nothing..." does it actually mean that it is putting
> a NO OP there?

For the null statement: Yep.

> Because then this would actually be doing something,
> most likely a timing issue, and that's what I need to know.

No. If SOME_EVENT_TOOK_PLACE is pure, the whole IF statement is a NO OP.
Otherwise it's the same as
  declare
     dummy : constant Boolean := SOME_EVENT_TOOK_PLACE;
  begin
     null;
  end;