Yes, the delay and force does the job. Now it would be nice to hide delay declaration in arguments destruction as already proposed:
(den mycrazyif [ statement ~onsuccess ~onfailure ] ; nonsuccess and on failure becomes delay objects (if statement ; just evalutated with mycrazyif call @onsucess ; deref block in case of success @onfailure)) ; deref block in case of failure On Tuesday, 26 April 2016 19:59:12 UTC+2, Michael Griffiths wrote: > > I'm not sure I fully understand your proposal, but when I really need lazy > evaluation (which is pretty rare) I reach for `delay` and `force`. > > On Tuesday, 26 April 2016 16:41:08 UTC+1, Olek wrote: >> >> Hi! >> >> In short: >> >> I have noticed that in most cases I use macros only for lazy arguments >> evaluation. Why not to make something to use only this feature? It would be >> light version of macro for clojurescript/clojure and easy to grasp for >> newcomers and still powerful in programming (with that you could implement >> binding/scopes/interpreter pattern). I love implicite use of macros where >> from call point of view the user can't distinguish what is function and >> what is macro. >> >> In long: >> >> Generally the macros are used in compile phase to manipulate AST (or just >> data structures because Clojure is homoiconic) to produce code in order to >> be consumed in evaluation phase. >> It is nice to include new language constructs with use of macros but as >> my experience points out for most time I use macros only for changing >> evaluation moment/order. >> Maybe there should be some construct like "defnlazy" for which you write >> normal function but all input arguments are evaluated only when you >> explicitly evaluate them. >> What we gain? We don't have to deal with # ` @ list eval and separate >> thoughts on read/eval phases, but we still must explicitly say ~ to deref >> passed block of construct as argument. >> >> Also there are some problems to grasp: >> - is it safe to implicite convert blocks of construct from statements to >> deref objects >> - how it should behave when you pass not deref object to another >> discussed "defnlazy" >> - maybe there shouldn't be any defnlazy but you should just implement it >> in arguments destruction so you can use constructs like: >> >> (defn mycrazyif [ statement ~onsuccess ~onfailure ] >> (if statement ; just evalutated with mycrazyif call >> @onsucess ; deref block in case of success >> @onfailure)) ; deref block in case of failure >> >> >> With regards, >> Olek >> > -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.