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: 103376,34d47d048b177d0b X-Google-Attributes: gid103376,public From: jsa@alexandria.synquiry.com (Jon S Anthony) Subject: Re: limited/non-limited in Ada95 Date: 1997/10/21 Message-ID: #1/1 X-Deja-AN: 284714092 Distribution: world References: <3442C2A3.3781@bix.com> Organization: PSINet Newsgroups: comp.lang.ada Date: 1997-10-21T00:00:00+00:00 List-Id: In article mheaney@ni.net (Matthew Heaney) writes: > I don't understand Henry's problem. If I implement a bank account as The problem he points out in the paper is quite clear IMO. > I agree that aliasing can comprimise the safely of a limited type (everyone > ought to read Baker's Limited Robbery paper), but if the programmer always > implements a limited private type by using a full view that is itself > limited - which one can do in Ada 95 - then there is no problem. There are important cases where this is at _best_ impractical and actually is more like not _feasible_. The _view_ for the implementation should not (can _not_) have limited semantics. This is particularly evident when you are constructing GC for Ada _within_ the language. Since this is one of Henry's main baileywicks, and since I've constructed such a GC asset suite _within_ the language, I can very easily understand where he is coming from. It's _painfully_ obvious when you have to actually deal with the situation. > If the programmer doesn't use a by-reference type, then it's a case of > programmer indolence, not a language problem. Rubbish. /Jon -- Jon Anthony Synquiry Technologies, Ltd., Belmont, MA 02178, 617.484.3383 "Nightmares - Ha! The way my life's been going lately, Who'd notice?" -- Londo Mollari