I created a ticket http://dev.clojure.org/jira/browse/CLJ-1508
2014-08-18 11:02 GMT+08:00 dennis zhuang <killme2...@gmail.com>: > I think that adding a :p option to destructuring would be great: > > (let [ {:keys [a b c] :p {a a-p}} params] > (if a-p > (println a) > (println "a is not exists."))) > > > > > > > 2014-08-17 20:05 GMT+08:00 Dave Tenny <dave.te...@gmail.com>: > > Well, it took me a while to perhaps get what you were telling me here. >> >> In my case I I had something like >> >> (defn foo [ & {:keys [bar ... more keys ...] :or {bar 1}} ] ...) >> >> and I wanted to know whether the user had explicilty invoked foo with >> :bar. >> >> What wasn't clear to me was that :as solved this problem. >> Reading http://clojure.org/special_forms#Special Forms--Binding Forms >> (Destructuring)-Map binding destructuring >> I guess I can see that it's telling me :as shows things that weren't in >> the init-form, but that's with hindsight. >> >> So, to emulated common lisp 'supplied-p' semantics, you can check the :as >> form, which will **not** >> contain :or values for keywords. >> >> E.g. >> >> user> (defn bar [ & {:keys [baz] :or {baz 'baz} :as all-keys} ] (println >> baz all-keys)) >> #'user/bar >> user> (bar :bof 1) >> baz {:bof 1} >> nil >> >> And not that the all-keys form does not show a binding for baz, and >> that's what I wanted. >> >> Just fyi in case anybody searches topics for 'supplied-p' again. >> >> >> On Saturday, June 21, 2014 7:22:13 PM UTC-4, Jason Felice wrote: >> >>> If you destructure the parameters like this: >>> (defn f [& {:as a-map}] ...) >>> >>> You can use map primitives on a-map. But you can also supply defaults >>> here. >>> On Jun 20, 2014 2:14 PM, "Dave Tenny" <dave....@gmail.com> wrote: >>> >>>> What is the commonly accepted technique for declaring/using >>>> 'supplied-p' type lambda list functionality in clojure? >>>> >>>> http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/ >>>> HyperSpec/Body/sec_3-4-1.html >>>> >>>> >>>> I have some clojure functions with a large number of keywords and >>>> various defaults, I want to know if a keyword was specified by the caller >>>> (rather than defaulted) in some cases. >>>> >>>> Certainly I could implement my own destructuring macros that did this, >>>> but I'd like to avoid reinventing a wheel here if I can, and also to know >>>> the idiomatic clojure way to do it. >>>> >>>> Thanks for any tips. >>>> >>>> >>>> -- >>>> 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 the Google >>>> Groups "Clojure" group. >>>> To unsubscribe from this group and stop receiving emails from it, 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. >> > > > > -- > 庄晓丹 > Email: killme2...@gmail.com xzhu...@avos.com > Site: http://fnil.net > Twitter: @killme2008 > > > -- 庄晓丹 Email: killme2...@gmail.com xzhu...@avos.com Site: http://fnil.net Twitter: @killme2008 -- 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.