Re: ADA compilers

[Jeff C <jcreem@yahoo.com>]

Patty wrote:
> Yes, we are trying to port an existing application.  I have looked at
> GNAT, but they only have ADA95.
> 

The issues involved with an update from Ada 83 to Ada 95 are <<= any 
issues you will run into with simply porting code from one compiler/os 
to another.

If the existing code makes use of a lot of vendor specific packages and 
it does not encapsulate it well, this will be a bit of work.

In any case if I were doing a bid (and I've done lots of them) the port 
from Ada 83 to Ada 95 would probably not even how up in the last digit 
compared to any other issues associated with the port.


What can be a bit more difficult (situation I have been in for a long 
time) is when you need the same (or mostly the same) codebase to be 
backwards compatible with the old compiler for some time. The only 
trouble in this case is just verifying from time to time that you did 
not "leak" any ada 95 features into your code base.

In any case I've got about 150K SLOC of Ada 83 that I also use with an 
Ada 95 compiler (with Ada 83 being the primary compiler still for a 
variety of reasons) and I've only got 1 file that is branched to make 
the Ada 83 work with the Ada 95 compiler because it is Ada 95 (note 
there are 5 or 6 other branched files but these are branched due to some 
vendor specific library issues or other areas that are due to vendor 
differences and not Ada language revision differences).