Dans comp.lang.ada, Gautier  �crit :

>What I mean: a program that translates Ada 95 code into
>"intermediate" Ada 83 code, referencing some packages
>like Interfaces, implementation of streams etc., eventually
>system-dependant.

You may want to have a look at GNAT's expansion mechanism:
GNAT first parses an Ada 95 compilation unit into an abstract
tree whose structure is close to that of the grammar as
specified by the RM, then rewrites parts of that tree to remove
all "complicated" constructs such as tagged types and tasking.
The resulting expanded tree is then handed to the code generation
machinry.

The expanded tree does not always correspond to valid Ada constructions,
but it is probably closer to Ada 83 than the original Ada 95 tree.
Depending on your precise needs, this might be an appropriate starting
point.

You can obtain an Ada-like rendition of the expanded tree using
the -gnatD command line switch.

Thomas.

-- 
    Thomas.Quinot@Cuivre.FR.EU.ORG