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From: "Wolf-Dieter Heker" <heker@aonix.de>
Subject: Elaboration Order
Date: 1999/11/15
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Date: 1999-11-15T00:00:00+00:00
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I think that Ada95 leaves too much freedom with respect to the elaborations
order of library units unless the user specifies lots of pragmas. This was
already the case in Ada83, although the introduction of elaborate_body
slightly improved the situation.
>From my point of view, most of the library packages ever written are 'simple
ones', i.e. they need no special treatment with respect to elaboration
order.  Hence I would suggest that these packages should contain an
elaborate_body pragma (except, of course, if the have no body). But alas,
most programmers - including myself ;-) - do not write these pragmas until
the get into trouble.
The lack of these pragmas is a portability issue. And isn't it true that if
a package body cannnot be elaborated immediately after the spec we have
generally a doubtful design? (This is not to say there might be no reasons
for such a structure, just that it would be more the exception rathern than
the rule.)

Now my major question: Why didn't the language designers choose an approach
that would make the standard case easy and provide a pragma
defer_elaboration_of_body for those rare cases, where the user doesn't want
the body elaborated immediately after the spec? Is there more reason that
just compatibility with the user unfriendly definition of Ada83?

Wolf-Dieter Heker