[m-dev.] for review: remove Prolog support

[Fergus Henderson]

On 15-Mar-1999, Peter Schachte <schachte at cs.mu.OZ.AU> wrote:
> On Mon, Mar 15, 1999 at 02:58:23PM +1100, Fergus Henderson wrote:
> > Yes.  The diff I posted yesterday included the following addition to
> > the NEWS file:
> > 
> > +  (Normally we would try to warn if any feature is to be removed at least
> > +  one release in advance.  However, in this case a simple work-around is
> > +  possible: in the unlikely event that anyone happened to have any makefiles
> > +  or scripts that depended on this support, they can install the latest
> > +  Mercury distribution and still continue to use the Prolog support from
> > +  Mercury 0.8, just by including the `bin' directories for both versions
> > +  in their PATH, with the more recent one first, of course.)
> > 
> > Do you think that is sufficient explanation?
> 
> I would suggest replacing the first sentence with:
> 
> 	Normally we would warn at least one release in advance if any
> 	feature is to be removed.
> 
> Also, I think it would be a good idea to put in a sentence stating why
> you've chosen not to follow that policy.  The existence of a
> workaround isn't really a reason, it just mitigates the inconvenience.

Here's what I've got now:

Index: NEWS
===================================================================
RCS file: /home/mercury1/repository/mercury/NEWS,v
retrieving revision 1.133
diff -u -u -r1.133 NEWS
--- NEWS	1999/03/07 14:02:28	1.133
+++ NEWS	1999/03/15 08:39:43
@@ -15,3 +15,27 @@
   See the "Interactive query commands" subsection of the "Debugger commands"
   section of the "Debugging" chapter of the Mercury User's Guide for details.
 
+* We've removed the support for using a Prolog debugger on Mercury programs.
+
+  Now that we have a working Mercury debugger, there's no longer any need to
+  use a Prolog debugger for debugging Mercury code.
+
+  Normally we would warn at least one or two releases in advance, if
+  any feature is to be removed.  However, in this case
+
+  	- it was an implementation feature rather than a language feature;
+	- the cost of maintaining the feature was quite high;
+	- the feature was already broken is various ways [one being that it
+	  doesn't work with the latest versions of SICStus Prolog, due to
+	  those versions removing support for a SICStus Prolog feature
+	  (save/1), apparently without any advance notice]; and
+	- a simple work-around is available if anything breaks as a result
+	  of the feature being removed. 
+
+  In the unlikely event that anyone happened to have any makefiles or
+  scripts that depended on the support for using Prolog, they can
+  install the latest Mercury distribution and still continue to use the
+  Prolog support from Mercury 0.8, just by including the `bin'
+  directories for both versions in their PATH, with the more recent one
+  first, of course.
+
-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.