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 X-Received: by 10.182.92.169 with SMTP id cn9mr1216344obb.45.1403633205788; Tue, 24 Jun 2014 11:06:45 -0700 (PDT) X-Received: by 10.182.20.204 with SMTP id p12mr23182obe.29.1403633205508; Tue, 24 Jun 2014 11:06:45 -0700 (PDT) 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!news.glorb.com!hn18no9111162igb.0!news-out.google.com!qf4ni15igc.0!nntp.google.com!uq10no7778712igb.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Tue, 24 Jun 2014 11:06:45 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=71.252.147.203; posting-account=zwxLlwoAAAChLBU7oraRzNDnqQYkYbpo NNTP-Posting-Host: 71.252.147.203 References: <255b51cd-b23f-4413-805a-9fea3c70d8b2@googlegroups.com> <5ebe316d-cd84-40fb-a983-9f953f205fef@googlegroups.com> <2100734262424129975.133931laguest-archeia.com@nntp.aioe.org> <5156oy7vhg99.17wu6q2ef45ke.dlg@40tude.net> <18et97c0c22vc$.y98lxxfblijn.dlg@40tude.net> <08f83f70-ccb1-45ec-8a4c-46e3442745b8@googlegroups.com> <557db566-fa02-4978-8798-50a097aa5407@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <690e9589-b410-428d-8691-fe45554a4982@googlegroups.com> Subject: Re: Ada platforms and pricing, was: Re: a new language, designed for safety ! From: "Dan'l Miller" Injection-Date: Tue, 24 Jun 2014 18:06:45 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Xref: news.eternal-september.org comp.lang.ada:20584 Date: 2014-06-24T11:06:45-07:00 List-Id: On Tuesday, June 24, 2014 10:55:15 AM UTC-5, Shark8 wrote: > On 24-Jun-14 05:25, Dan'l Miller wrote: > Something where state-machines are first-class citizens seems like an=20 > appropriate use for a DSL. Ah, yes, domain-specific languages (DSLs) are yet another area that Ada202X= could address as a claim to fame that would differentiate Ada202X from, sa= y, C++ and Java and Swift, given that OCaml with p4, MetaOCaml, and Seed7 a= re already (imperfectly) blazing portions of that DSL trail. Stage-n sourc= e code that teaches the Ada202X compiler a DSL at stage n to produce stage-= n+1 source-code generation feeding into stage n+1 Ada202X compilation would= put Ada back on the map. Plus, full-fledged support for multistage progra= mming via DSLs within an extensive multistage Ada202X compiler would likely= solve not only the FSM problemspace well, but also could permit errors to = be domain-specific errors to be detected at compile-time (at either stage-n= or at stage-n+1 compilation) instead of at run-time, allowing Ada202X to o= ne-up the dynamic-programming world. For example, the dynamism of Objective-C & Swift at run-time would be moved= to one of the later stages of multi-stage programming. As another example, one of the A#1 uses of Objective-C's & Swift's *run-tim= e* check of whether a method is implemented for a target object is for a GU= I infrastructure and the app-domain usage there of to defer which object in= a hierarchy of nested 2D widgets to process an event (e.g., mouse-click; b= utton press; keystroke) at not necessarily the leaf widget and not necessar= ily the root widget/canvas, but rather any leaf-or-intermediate-or-root wid= get-node from leaf to root. Some events are appropriately naturally discar= ded if no handler processes that event by the time that the leaf-to-roof wa= lk completes for that containment chain of widgets at those coordinates (or= in the case of keyboard: the widget with focus). But some events would b= e considered an error if no widget handled them during the leaf-to-root wal= k of widgets at those coordinates (or in the case of keyboard: the widget = with focus). Hence, GUIs have a cross-cutting analogue of what is abstract= versus concrete in OO polymorphism, but for GUIs the tree is not a tree of= types of classes; rather for GUIs the tree is a containment tree as a like= ly-heterogenous n-ary tree of different types of widgets. That eventual co= ncreteness could be enforced across each leaf-to-root walk of a containment= tree of widgets for a given window or for a given dialog box. This is whe= re a multistage compiler could really shine (and perhaps a multistage compi= ler with GUI-expressivity DSL capabilities), because it can analyze where a= ny events that need to be handled are not handled along one or more leaf-to= -root walks of that containment tree. This is currently a run-time error-c= ase in Objective-C and Swift, but need not be, because with the correct com= pile-time-philosophy-based programming-language such as Ada202X (and perhap= s with a DSL among a multistage Ada202X compilation) has not been brought t= o bear on that problemspace. Imagine putting Ada back on the map as the pr= emier language for a whole new problemspace, mainstreaming compile-time che= cks for what has been until now various domain-specific run-time errors in = all of the plethora of mainstream programming languages, which is precisely= the special sauce that put Ada on the map back in the late 1970s and throu= ghout the 1980s as the one to beat.