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=-0.8 required=5.0 tests=BAYES_00,INVALID_DATE, MSGID_SHORT autolearn=no autolearn_force=no version=3.4.4 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!hellgate.utah.edu!dog.ee.lbl.gov!nosc!cod!sampson From: sampson@cod.NOSC.MIL (Charles H. Sampson) Newsgroups: comp.lang.ada Subject: Re: procedural variables Message-ID: <2834@cod.NOSC.MIL> Date: 15 Feb 91 18:32:11 GMT References: <9102110959.aa23851@PARIS.ICS.UCI.EDU> <662@esosun.UUCP> <24590@neptune.inf.ethz.ch> Organization: Computer Sciences Corporation List-Id: In article <24590@neptune.inf.ethz.ch> mneerach@iiic.ethz.ch writes: > >Could anybody explain what the rationale for not including procedural >variables in Ada is (I have heard it has been discussed and dismissed again >in the past few years) ? I've been searching for some pertinent ancient documents, but without success, so I'm going to have to rely on memory. Probably everybody remem- bers that Ada is the result of an effort by the U. S. Department of Defense. This effort had a limited scope: to define a single computer language that could be used for all embedded computer applications within the DoD. (An embedded computer is one that is a part of a larger system, such as an air- craft or a smart torpedo.) This was a well executed project. It began with a survey of many of the groups withing the DoD, to determine what capabili- ties were required, followed by a set of successively refined requirements documents. As I remember it, one result of this survey was that there was no need at all for procedural variables (in DoD embedded computer applica- tions). I also remember that the first requirements document (called Straw- man; this is the one I can't find) explicitly stated that the language would not have such a capability. In the successors to Strawman the requirement was stated positively in terms of the current three formal parameter modes. Incidentally, at one stage of this process the capability that ulti- mately became exceptions was defined as a fourth formal parameter mode. Charlie