On Fri, Jan 29, 2010 at 9:40 AM, Chouser <chou...@gmail.com> wrote: > On Fri, Jan 29, 2010 at 8:44 AM, Rich Hickey <richhic...@gmail.com> wrote: >> On Fri, Jan 22, 2010 at 8:57 AM, Chouser <chou...@gmail.com> wrote: >>> On Thu, Jan 21, 2010 at 10:11 PM, Sean Devlin <francoisdev...@gmail.com> >>> wrote: >>>> Sometimes you don't want assoc-in to create a hash-map. Sometimes you >>>> wish it could create a sorted map. >>>> >>>> Just finished working on something with Alexy Khrabrov & Chouser on >>>> IRC, and the three of us are wondering if the result might be >>>> generally useful. >>>> >>>> (defn assoc-in-with >>>> "supply a default-map instead of a hash-map" >>>> [m default-map [k & ks] v] >>>> (if ks >>>> (assoc m k (assoc-in-as (get m k default-map) default-map ks v)) >>>> (assoc m k v))) >>> >>> As I mentioned in IRC, this could actually be a 4-argument >>> version of 'assoc-in' instead of a new function. Assuming of >>> course Rich likes the idea. >>> >> >> Where would the default go? Also, need it be a map, vs anything >> associative (e.g. a vector)? > > Since update-in could use this pattern as well, I don't think the > default should go after the value (or update fn) position. > I think where Sean put it is fine -- after the collection, before > the vector of keys. >
As soon as you are varidic with update-in I think you'll need new names, i.e. can't just add another arity to assoc-in and update-in. > I don't see why it needs to be restricted to a map -- all the > normal assoc rules apply. > Right. I wonder though, if a single default coll is sufficient. There are potentially multiple levels to the structure, using different data structures at each level. 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
