Re: Estimating conversion of Ada 83 to Ada 95

["Robert I. Eachus" <eachus@mitre.org>]

"Terry J. Westley" wrote:

> We're converting a 640 KSLOC real-time, distributed simulation from
> Ada 83 (VADS) to Ada 95.  I expect most of the work will be replacing
> VADS-specific packages with Ada 95 library packages and POSIX packages.

> Based on some limited conversion work we've already done, I'm using
> 162 LOC/Hour for converting from VADS to GNAT Ada 95 for those files
> which include lots of special stuff such as OS calls, use of VADS
> packages, use of Oracle Pro*Ada, etc.  For the rest, I figure it'll
> be at least 5 times faster than that, for a conversion rate of
> 812 LOC/Hour.  This includes conversion, compilation, and testing.

    If the Pro*Ada stuff is pervasive, the estimate is very optimistic.
Pro*Ada is the one area where I have found that you are often better off
rewriting using ODBC or some such.  Maybe you can convince Oracle to
create GNAT versions of the support packages for Pro*Ada, but in the
cases I have converted, using a vendor independent interface had two
benefits:

    1) I wouldn't have to do it again.
    2) The size of executables shrank significantly.
 
> I expect we'll use the GNAT Ada83 switch for the first pass, then
> turn it off to see what happens.

    You can, but I have never found much benefit from it.  It is much
more useful for making sure your code is Ada 83 compatible.

> Anyone have any evidence that I'm way off on this estimate?

    Pro*Ada is one that I almost mentioned on the Team Ada list.  I've
tried going the minimal conversion route and not been very happy.

-- 

                                        Robert I. Eachus

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