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=-1.9 required=5.0 tests=BAYES_00 autolearn=unavailable autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!peer02.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!nntp.club.cc.cmu.edu!micro-heart-of-gold.mit.edu!newsswitch.lcs.mit.edu!nntp.TheWorld.com!.POSTED!not-for-mail From: Robert A Duff Newsgroups: comp.lang.ada Subject: Re: Pass a serial port as user data in a GTK callback handler? Date: Mon, 17 Feb 2014 16:31:26 -0500 Organization: The World Public Access UNIX, Brookline, MA Message-ID: References: <050a1b45-c312-4fff-96f9-7c3d01466500@googlegroups.com> <58fb9abc-1892-4a36-9895-c494dbc727c9@googlegroups.com> NNTP-Posting-Host: shell01.theworld.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: pcls7.std.com 1392672690 9643 192.74.137.71 (17 Feb 2014 21:31:30 GMT) X-Complaints-To: abuse@TheWorld.com NNTP-Posting-Date: Mon, 17 Feb 2014 21:31:30 +0000 (UTC) User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (irix) Cancel-Lock: sha1:BgaPzoFou46GrJFDiLBato68ojo= X-Received-Bytes: 2138 X-Received-Body-CRC: 1993918097 Xref: news.eternal-september.org comp.lang.ada:18649 Date: 2014-02-17T16:31:26-05:00 List-Id: adambeneschan@gmail.com writes: > To expound on this a bit, since you mentioned you were overwhelmed by > the complexity of the language: This particular inconsistency is there > because of backward compatibility. Ada 83 did not have access types > that could point to variables, nor did it have anonymous access types. > Those were added in Ada 95. The Ada 95 designers decided that since > Ada 83 access types didn't have to be implemented as addresses, it was > necessary to have some way to distinguish between an access type that > could point to a variable and an access type that was required to > point to something allocated with "new"; in order not to break > existing Ada 83 programs, the "access all" type was added, which I'm > sure they hated having to do... We didn't have to do it, and Tucker didn't want to do it, but I convinced him it was a good idea. I later realized I was wrong, too late. Mea Culpa. >... (adding the extra keyword) "all" was already a keyword in Ada 83, so I guess you mean "adding it to the syntax for access types". >..., but sometimes > there just isn't a good solution. - Bob