Understood. I was using a configuration example as a kind of shorthand for a larger set of problems - most of which are multithreaded and will be dealing with occasionally changing results. As usual, its a tricky area, but not as difficult as achieving the same result in some other environments, fortunately.
On Wednesday, December 10, 2014 11:22:39 AM UTC, Gary Verhaegen wrote: > > Although if you do not expect the config to change, you do not need to > wrap the delay in an atom. The atom in Steven Yi's solution is only there > to allow the combination of (delay) executing the operation strictly once > but also (atom) allow for changing the underlying value (i.e. clear the > cache). > > On Wednesday, 10 December 2014, Andy Dwelly <andyd...@gmail.com > <javascript:>> wrote: > >> Thanks to everyone for the responses. I was completely unaware of >> core.memoize although I think there is a very convincing case for delay; I >> certainly accept the thread safety problem with the existing code. Action >> this day on that one! >> >> I'm inclined to go down the @@ syntactic route, simply in order to enjoy >> the look of horror on my co-worker's faces when I check it in. >> >> On Wednesday, December 10, 2014 4:45:16 AM UTC, Steven Yi wrote: >>> >>> No reason really, just ended up writing it that way for the example. >>> (Maybe subconsciously I didn't want to think about pointer pointers >>> and wanted to break up the notation. :P) >>> >>> On Tue, Dec 9, 2014 at 11:18 PM, Fluid Dynamics <a209...@trbvm.com> >>> wrote: >>> > >>> > >>> > On Tuesday, December 9, 2014 7:19:27 PM UTC-5, Steven Yi wrote: >>> >> >>> >> Hi Andy, >>> >> >>> >> Just my two cents here, but I don't think memoize makes sense here >>> myself >>> >> due to this not being referentially transparent, and I think Andrey's >>> >> comment on delays makes more sense to me. You could do something >>> like this: >>> >> >>> >> (def conf (atom (delay (read-and-expensively-parse "somefile.xml")))) >>> >> >>> >> (defn config [] >>> >> @(deref conf)) >>> > >>> > >>> > Why not just @@conf? It seems to work at my REPL, at least, to unpeel >>> two >>> > onion layers of indirection. >>> > >>> > -- >>> > You received this message because you are subscribed to the Google >>> > Groups "Clojure" group. >>> > To post to this group, send email to clo...@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+u...@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 a topic in the >>> > Google Groups "Clojure" group. >>> > To unsubscribe from this topic, visit >>> > https://groups.google.com/d/topic/clojure/FaPliPRgJBI/unsubscribe. >>> > To unsubscribe from this group and all its topics, send an email to >>> > clojure+u...@googlegroups.com. >>> > For more options, visit https://groups.google.com/d/optout. >>> >> -- >> 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. >> > -- 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.
