Don't have time to go in depth on an explanation. But remember that m- bind must work with m-result according to the 3 monadic laws. This constrains what it can do. Don't know if you saw, but I did a whole tutorial on the continuation monad. It's at:
http://intensivesystems.net/tutorials/cont_m.html Jim Steven E. Harris wrote: > In clojure.contrib.monads, there's a monad defined called "cont-m" to > model continuations. Its bind operator -- `m-bind` -- is defined as > follows: > > ,---- > | (fn m-bind-cont [mv f] > | (fn [c] > | (mv (fn [v] ((f v) c))))) > `---- > > I'm curious why there's an extra delaying wrapper function there. The > outermost `fn' form taking the argument "c" as a continuation looks like > it serves only to delay evaluation of the remaining forms. > > The parameter "mv" is a monadic value which, for the continuation monad, > is a function accepting a single continuation argument. The parameter > "f" is a monadic function which, again, for the continuation monad, is a > function accepting a value offered by a continuation and returning a > monadic value -- another function accepting a single continuation > argument. > > If all of that is true, then the form > > ,---- > | (f v) > `---- > > should evaluate to a monadic value and be suitable as a return value > from `m-bind'. In short, why is this not an acceptable implementation? > > ,---- > | (fn m-bind-cont [mv f] > | (mv (fn [v] (f v)))) > `---- > > -- > Steven E. Harris -- 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
