Re: AQ&S Guidance on pragma Elaborate_Body

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Bob said

<<I just wish that (1) I didn't have to write zillions of pragmas in the
"normal" cases.  E.g. maybe Elaborate_Body or Preelab should be the
default, with a pragma to turn it off.  And (2) that all implementations
had to choose the same order for a given program.  The Modula-2 rules
are closer, but still don't quite make it.>>

In its default configuration, GNAT 3.10 does not require you to write
"zillions of pragmas", and guarantees that Program_Error cannot occur.
Now it is true that you can construct programs that are treated as
statically illegal in this default mode, when they are in fact legal,
but in practice we have found that the rules we implement (which basically
assume pragma Elaborate_All if not stated where needed because of access
from elaboratoin code) seem to work for a very large subset of programs.

So far, we have only found a few ACVC tests that defeated these static
checks. We will know more when more people have a chance to try out this
new approach.

Robert Dewar
Ada Core Technologies.