From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,1e4280c6ade7eb23 X-Google-Attributes: gid103376,public From: dewar@merv.cs.nyu.edu (Robert Dewar) Subject: Re: Exception types? Date: 1998/06/21 Message-ID: #1/1 X-Deja-AN: 364717356 References: <3584F47B.3ADF7442@elca-matrix.ch> X-Complaints-To: usenet@news.nyu.edu X-Trace: news.nyu.edu 898439338 16159 (None) 128.122.140.58 Organization: New York University Newsgroups: comp.lang.ada Date: 1998-06-21T00:00:00+00:00 List-Id: <<> The proposal was in the mapping, but was removed. Maybe someone who > participated actively in the language design can tell us why ? >> There was a LOT of stuff in the mapping documents. There was virtually unanimous agreement (with only the design team dissenting) that in aggregate the design was far too extensive. So it had to be cut back. This feature in particular was one that introduced a lot of implementation complexity for insufficient gain, and there was general agreement that it had too low a value-to-effort ratio. Note that this does not mean that in isolation this feature was "bad" (there is nothing wrong per se with the last straw on the camel's back :-) Note that I think the general level of change turned out about right. Most (but still not all) Ada vendors have managed to upgrade to Ada 95 (GNAT acted as a useful nudge). We still have at least one vendor remainin committed to Ada 83, and one major vendor that dropped out completely (Digital) and one of the reasons for that dropout was (as Bevin has noted), the extent of the change. We also had one Ada technology drop out of site (the old Alsys technology) as a direct result of the fact that the change was too extensive. SO I think we compromised at a reasonable level. We lost some implementations but kept the majority. If we had accepted everything in the mapping team's design document, I think we would have far fewer Ada 95 compilers on the market today (perhaps none). That being said, at this stage, it is very worthwhile to go back and look at some of the (very good) suggestions that were dropped. Another example of a feature worth looking at for example is the extension of 'Class to non-tagged types. There are many others. At this stage, it would be definitely interesting on a research project basis to attempt adding some of these features to experimental versions of GNAT (this is one of the advantages of having the sources available!)