On Jul 1, 2015, at 1:13 PM, Neil Toronto <neil.toro...@gmail.com> wrote:
> On 07/01/2015 10:47 AM, John Carmack wrote: >> >> S-expressions actually are one of the core wins from my use of lisp so far >> -- embracing read/write (and the associated bandwidth cost) as a wire >> protocol over yet another hand crafted binary format has been a significant >> win (however, the flexibility of the win seems to fight with static typing, >> perhaps at a fundamental level, in my limited typed-racket experience so >> far -- a good topic for discussion?). > > Definitely a good topic for discussion. > > Where do you predict fights with static typing? Or, if it's just a general > feeling based on past experience with static typing, how do you expect to use > it? > > There's every chance that Typed Racket's union types, singleton symbol types, > and occurrence typing will make it fairly easy to type an s-expression-based > wire protocol; e.g. > > (define-type Command (List '<command-name> <arg-types> ...) > (define-type Commands (Pair 'begin (Listof Command))) > (define-predicate valid-commands? Commands) > > At a rough count, I've written more than 100,000 lines of Typed Racket code, > much of which has had to be available to call in untyped Racket without > significant performance loss. I admit that Typed Racket is the only Racket > language that has made me want to throw things, but that's increasingly rare, > it's been much more pleasant than other type systems I've used, and I'm > pleased with the guarantees and increased performance I've gotten from it. Let me add one thought here. One of the thoughts I have played with in this context is to have a dissertation on XML-style type extensions for Typed Racket (CDuce, XDuce). I am not interested in XML (or JSON) per se but in type systems that can say more about S-expression-like data. Of course, as in the past, this would have to be balanced between theoretical expressive power and practical expressiveness/impact. (We tend to err in the direction of the former, because we finance Racket via research grants.) In a way, TR's union-type system ought to make an integration of these ideas simpler. You could then successively refine types of S-expressions and verify more claims about them if this played a role in your program. But as Neil and Tony said, the type system gets in your way with such things, but no longer enough to be annoying. -- Matthias -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
