On Thu, 2008-03-13 at 15:08 +0000, Sam Mason wrote: > No, it's a special operator that only the compiler could provide because > it returns a by-ref. For example: > > (proclaim asref : (fn (mutable 'a) (by-ref (mutable 'a)))) > > (define (inc (x : (by-ref (mutable int32)))) > (set! x (+ x 1))) > > (define (f (x)) > (inc (asref x)) > x)
At the moment, the ASREF is completely unnecessary. > If this function existed, then you'd never want to allow the compiler to > infer a by-ref to a mutable object. It would probably also want to get > a nicer name/symbol. The compiler doesn't need to infer that here. The BY-REF is stated explicitly in the formal parameter type. I am unclear. Is your goal to make the taking of the reference explicit at the location of the use occurrence? That might very well make sense. > > So, are you suggesting that if we write (by-ref 'a), where 'a cannot > > unify with a mutable type? This cannot be the case since the type > > variable must be able to unify with any type. > > Yes, and that's why it's all a bit nasty. This is still all coming from > a comment a long time ago that's stuck in my head about auditing and > seems to have taken on a life of its own. I think that annotating the ref-taking at the call site might not be a bad idea, but I don't think this is something that needs to be fixed today. We're about to do a complete syntax overhaul in any case, and we take this up then. shap _______________________________________________ bitc-dev mailing list bitc-dev@coyotos.org http://www.coyotos.org/mailman/listinfo/bitc-dev
