On Thu, Sep 1, 2011 at 2:08 PM, Alan Malloy <a...@malloys.org> wrote: > Well, the two calls to subseq are unpleasant and possibly slow. I was > thinking there's a way to write it as a single operation that returns > three items, say (subseq s >= (dec 50)) to get the items before and > after 50, but of course that doesn't work unless you know 49 is in > there, and in that case why bother with subseq? > > It's a bit galling, because the sorted-set *knows* how to get to where > 50 should be, and how to walk in either direction from there, but in > order to walk in two different directions you have to walk down from > the root twice. Maybe it'd be nice to have a (get-walker s 50) that > you can later pass directions to, to walk through the set in whatever > order.
A less-Clojury solution would be to have sorted-set implement List, and provide something like get-walker that yields a ListIterator on the specified element, or the next higher if any, or one past the end otherwise, or whatever. Of course a ListIterator is a mutable Java object. A Clojury solution would be a function that traverses from the root and then generates a return value equivalent to [(rsubseq s x) (subseq s x)], except not performing two traversals to generate it. The caller can destructure this and use the two seqs. -- Protege: What is this seething mass of parentheses?! Master: Your father's Lisp REPL. This is the language of a true hacker. Not as clumsy or random as C++; a language for a more civilized age. -- 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
