On May 26, 5:13 pm, Michael Jaaka <michael.ja...@googlemail.com> wrote: > Hi! > > I have some suggestions about transients (btw. > thehttp://clojure.org/transients > is not linked fromhttp://clojure.org). > > Maybe before you give up reading the whole post I will post as first > the digression: > vars binding and transient are similar, however in the first case we > have thread isolation on reading and writing with reference covering/ > hiding ability. Currently operations on transients structures seems to > be badly interfaced in Clojure and below is a deal: > > Why do we have to deal with conj! and rest of foo! operations, when > there are much more functions like update-in, assoc-in etc. what about > them? In most my code I fail to use transient because of xyz-in > operations. More over I know that the code is whole executed by one > thread, since I know where the transient structure starts to exist and > when it ends. Tracking such code is easy task to do since most fast > compuations are free of side effects and thread intercommunication. > > If the whole talk is about thread isolation (which is great feature), > then the interface should be simplified, in the way like - (transient > x) - attaches thread (which calls transient) reference to my structure > (object), when any other thread tries to modify x then the exception > is thrown. When I do (persistent x), the thread reference is detached > from the structure, so it becomes persistent and others threads can > concurrently modify it. > > This would eleminate duplication of functions and allow for single > threaded computations. This would satisfy most computations related > with reduce operation and recurention. So easy to do, so easy to > track, yet not in Clojure ;-(. The (transient x) and (persistent x) > are required since the are explicit declaration of single thread > mutation. > > Also it would be nice if such transient structures could be used in > binding clasues, since I have found other adoption - for example > thread is doing computations in a functional way - and with binded > transients I'm gathering statistics (time measurement, bytes counting > etc. in an imperative, side effecting, more like aspect way.) > > What are your thoughts? >
The problem is that the semantics of conj and conj! are quite different. The first promises to return a persistent immutable value and the second promises the opposite. > BTW. What does it mean "don't bash in place" - since for not all > people English is not a native language I suggest to use simpler words > in such formulations. It means, modify in place by repeated interaction with the same object, as in OO: x.changeThis() x.changeThat() x.changeTheOther() or, in Clojure with a transient: ;;this is bad, don't do this (let [x (transient y)] (conj! x this) (conj! x that) (conj! x theOther)) the above Clojure structure would never arise by following the guidelines of writing it functionally first. Rich -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
