From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on ip-172-31-74-118.ec2.internal X-Spam-Level: X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.5-pre1 Date: 30 Jul 93 22:17:50 GMT From: agate!howland.reston.ans.net!noc.near.net!inmet!spock!stt@ucbvax.Berkeley .EDU (Tucker Taft) Subject: Re: Porting to Ada 9x Message-ID: List-Id: In article <1993Jul29.134804.17614@aio.jsc.nasa.gov> ddanley@gothamcity.jsc.nasa.gov writes: >In the Ada 9x compatability guide, Bill Taylor stated that there >are 32 upward incompatabilities between Ada 83 and Ada 9x. >Are there only 32 upward incompatabilities to the 9x specification? Actually, the number of upward incompatibilities has dropped since Bill Taylor's initial report was released. In any case, almost all of the incompatibilities are straightforward to accommodate, as the compiler detects them or can warn the programmer of them, and the fix is relatively mechanical (e.g. add an underscore to the end of an variable name that is now a reserved word). There are a few incompatibilities that are a bit more difficult -- for example, the number of characters in Standard.Character has gone from 128 to 256. This changes the value of Character'Last, and means that the programmer has to decide how they want to handle 8-bit characters as opposed to Ada 83's 7-bit characters. To ease transition, this change has been approved for Ada 83 compilers, so compilers can start supporting the 8-bit character model, and programmers can get a jump on handling 8-bit characters properly. It is also anticipated that Ada 9X compilers will warn users during the transition period when they encounter references to values such as Character'Last that have changed. S. Tucker Taft stt@inmet.com Ada 9X Mapping/Revision Team Intermetrics, Inc. Cambridge, MA 02138