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,FREEMAIL_FROM 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!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail From: Victor Porton Newsgroups: comp.lang.ada Subject: Re: Dynamic type system for Ada Date: Fri, 27 Jan 2017 21:20:33 +0200 Organization: Aioe.org NNTP Server Message-ID: References: <874m0nlmqw.fsf@nightsong.com> NNTP-Posting-Host: eAyfEuoyb82Xkl8rYnvycQ.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit X-Complaints-To: abuse@aioe.org User-Agent: KNode/4.14.10 X-Notice: Filtered by postfilter v. 0.8.2 Xref: news.eternal-september.org comp.lang.ada:33202 Date: 2017-01-27T21:20:33+02:00 List-Id: Paul Rubin wrote: > Victor Porton writes: >> Due to pure curiosity, I ask: Has anybody developed a dynamic type system >> for Ada? > > That's not so easy. You have to be able to wrap an arbitrary Ada object > in another object, along with a tag saying what the Ada type is. That > means you have to be able to encode every Ada type into a tag, and types > can be quite complicated (maybe arbitrary tree structures even). Also > the compiler might or might not have a way of telling the runtime what > type something has. In my initial request there was no proposal to encode arbitrary Ada object. > There is something like this in Haskell called Data.Dynamic, but they > had to add special features to the compiler and runtime to support it. -- Victor Porton - http://portonvictor.org