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!feeder.eternal-september.org!aioe.org!.POSTED.fn3LatRFkm9/xzEj7F2/NQ.user.gioia.aioe.org!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Ada in command / control systems Date: Tue, 5 Mar 2019 17:09:39 +0100 Organization: Aioe.org NNTP Server Message-ID: References: <2199b15b-d704-403f-a6c4-00fab29792d5@googlegroups.com> <72738cc8-3f65-4cc1-8c61-b1166cb5e3c2@googlegroups.com> <9807ec3a-4c34-4641-acfa-e9cf22de95ce@googlegroups.com> <51611452-1f49-4d8d-b93d-363cbbee29d0@googlegroups.com> <6a0fe4c2-a8e6-4d15-8cbf-f5a85ba0cd86@googlegroups.com> <1a5fae09-bbbf-4bdb-be8c-6a2e3fd70dfa@googlegroups.com> NNTP-Posting-Host: fn3LatRFkm9/xzEj7F2/NQ.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.9.2 Xref: reader01.eternal-september.org comp.lang.ada:55788 Date: 2019-03-05T17:09:39+01:00 List-Id: On 2019-03-05 10:33, Maciej Sobczak wrote: >> Rather incompleteness and/or lack of usability. > > But why do you expect a single tool to be complete, if we can get completeness from the combination of tools? Because the tool is claimed to state the "requirements". There can be nothing above that. > From what G.B. wrote in a sibling post, it looks like source code alone is not complete and usable in some contexts, either. The source code is complete per definition, otherwise you could not compile and build the solution from it. > But nobody would like to do it. So everybody accepts technology mixes for the sake of work efficiency. My point was that the technology is basically same. > That's why nobody complains about s-functions, it just looks like any other mix. Apart from the issue of being "requirement" rather than code, the difference is technical impossibility to implement things in Simulik on one side and mere reuse of existing components on another. >> You have a huge system integration problems caused by language >> impedance > > No. This integration happens at a lower scale, so it is not a system problem. I can call s-function written in C (or Ada!) form the Simulink model without much concern about language impedance. There are lots of concerns when calling s-function, e.g. when the block containing this function is in the feedback loop. Models are extremely fragile. Using s-functions is like throwing arbitrary assembler insertions into Ada code. When you couple two models from two different frameworks what would be the effect? Programming languages have means for proper encapsulation and insulation the side effects. Domain-specific languages have nothing of this sort. > I think that calling Ada functions from Python is more involved, even though they share paradigms. > >> which becomes impossible when you have to connect models from >> different paradigms. You must break out of one model go to a reasonable >> language and then re-enter into yet another model. > > And what can prevent me from doing it? If I call C functions from Ada, the integration is actually happening at the object level (by linker, not by compiler), because these languages do not much care about each other. It is the same paradigm and after a half of century we more or less know how to write reusable components in C and Ada. >> Better. This debunks the whole argument about pseudo-requirements. How >> can you write requirements in a model language bounds of which >> applicability and the role in the whole system is unknown? > > Making this judgement is the responsibility of person doing tool evaluation. Experience with previous projects helps. I am talking about the architecture. The requirement telling not to implement the client DB in Simulink are written in Simulink? > This is an interesting observation, and perhaps related to the bigger notion of change that is slowly happening. But still, it has nothing to do with model-based engineering. It has to do with how much of free space is left for using garbage paradigms that have no technical merits. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de