I think the below would make a good PLT blog post, perhaps with an opening paragraph about how much cheaper the stateless web-server can be.
John On Jan 3, 2012, at 10:33 PM, Galler wrote: > > > On the subject of porting #lang racket to #lang web-server code > > I provide a few lessons learned for the archives for the next person to > attempt this. > > > 1) Bindings, Serializability , and anonymous functions > > 1A) the predicate serializable? from racket/serializable is invaluable > > #lang web-server code will not transform if there are non-serializable > constructs in the dynamic extent of the invocation of send/suspend > > some minor surprises/lessons learned: > > 1B) anonymous functions are not serializable > > (serializable? (λ (x) x)) ;->#f > > 1C) anonymous functions in a list are not serializable > > (serializable? (car (list (λ (x) x) (λ (x) x)))) ;->#f > > 1D) once given a module-level binding, anonymous functions become serializable > > (define foo (list (λ (x) x) (λ (x) x))) > > (serializable? (car foo)) ;->#t > > 1E) void is not serializable > > (serializable? void) ;->#f > > 1F) anonymous functions bound within a letrec form are serializable > > > 2) 'attempt to cross a continuation barrier' exceptions > > invocations of native continuations reified with call/cc seemed to frequently > throw this error > > I haven't done enough analysis to understand why and under what conditions, > but in all cases I was able to remediate by enclosing the invocation as > follows. > > (call-with-continuation-prompt k (default-continuation-prompt-tag) > > 3) with-continuation-marks, continuation-marks, and > current-continuation-marks can be used to replace dynamic-wind > > > Again, thank you. I think the stateless web-language is important technology > and must have required an enormous amount of work to implement. > > Anedcotally, application speed seems at or better than the stateful code. > > R./ > Zack > > On Sun, Jan 1, 2012 at 4:36 PM, Jay McCarthy wrote: > > > On Sat, 31 Dec 2011 20:03:02 -0600,Robby Findler > > <ro...@eecs.northwestern.edu> mumbled: > > > I'm not sure if the web-server supports continuation marks or not > > > > The stateless transformation does support continuation marks, provided > > the keys and values are serializable. (Parameters/exception handlers are not > > supported because the key is not serializable.) > > > > Jay > ____________________ > Racket Users list: > http://lists.racket-lang.org/users
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