Those are known as "semantic brackets." They denote a syntactic form into its ideal mathematical object. In a sense, they give "meaning" to what they surround. -Ian ----- Original Message ----- From: Patrick Li <patrickli.2...@gmail.com> To: Matthias Felleisen <matth...@ccs.neu.edu> Cc: users@racket-lang.org Sent: Thu, 24 Nov 2011 17:05:30 -0500 (EST) Subject: Re: [racket] Implementing delimited continuations using a CPS transform
Thanks for the feedback. The literature references are extremely helpful, and I will read through them carefully. As an aside, may I ask what notation is being used in these papers? I thought it might be lambda calculus, however I cannot determine what it means to surround an expression using calligraphic []'s. -Patrick On Thu, Nov 24, 2011 at 7:01 AM, Matthias Felleisen <matth...@ccs.neu.edu>wrote: > > > On Nov 24, 2011, at 9:52 AM, nicolas.o...@gmail.com wrote: > > >> But you could also break the tail-call discipline of CPS and translate > [shift e] as \k. (k [e](\x.x)) > >> Or you can use our 'abstract' continuations to manipulate a stack of > continuations directly. > > > > What are your 'abstract' continuations? Sounds very interesting. > > > See LFP 1988. When I first invented prompts and functional continuations, > I did not know how > to assign a denotational meaning to them, i.e., a translation from syntax > to sets of denotations. > Or how to write a TCO interpreter that has the right properties. The key > insight was that you > don't have to have monolithic functions as continuations with just one > operation on them > (composition). Instead you can use any ordinary algebra of combinators > that combine small > pieces (functions) into the whole thing (continuation) and use them > (throw). Best of all, > if you look at the initial model of a simple stack algebra, you get the > standard notion > of continuations and if you look at the final interpretation, you get a > stack of functions, > which you can then use to do prompts/F prompts/C prompts/callcc. One of > these combinations is > shift/reset, as reinvented by them. I forgot which one. -- Matthias > > _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
