[m-dev.] for review: document backwards compat concerns in NEWS file

[Fergus Henderson]

Estimated hours taken: 0.25

NEWS:
	- warn about the backwards compatibility implications
	  of the change to add function versions of the standard
	  library predicates.

Workspace: /d-drive/home/hg/fjh/mercury
Index: NEWS
===================================================================
RCS file: /home/mercury1/repository/mercury/NEWS,v
retrieving revision 1.153
diff -u -d -r1.153 NEWS
--- NEWS	1999/11/23 08:13:40	1.153
+++ NEWS	1999/11/24 05:48:34
@@ -127,6 +127,16 @@
 * We've added function versions of many of the predicates in the
   Mercury standard library.
 
+  One small drawback of this change is that it is not completely
+  backwards compatible; in certain circumstances, there is a potential
+  ambiguity between a function call and a partially applied predicate,
+  and for some ocurrences of this the compiler may not be able to
+  resolve the ambiguity unless the user provides additional type
+  declarations (or the like).  But such cases should be quite rare,
+  and when they do occur the fix is easy, so we though the clear
+  advantages of using a functional syntax were well worth this
+  minor glitch in backwards compatibility.
+
 * The following predicates have been replaced by functions with
   the same names, and will be removed in a future release.
 

-- 
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.
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