On Fri, Jul 8, 2011 at 1:06 AM, David Nolen <dnolen.li...@gmail.com> wrote: > On Fri, Jul 8, 2011 at 1:00 AM, Ken Wesson <kwess...@gmail.com> wrote: >> >> > On Thu, Jul 7, 2011 at 11:21 PM, Ken Wesson <kwess...@gmail.com> wrote: >> >> ... it won't use the protocol to cache the result. Making it do so, >> >> however, >> >> would cause problems if one had (seqable? some-foo) and later attempted >> >> to extend the protocol to mark Foos as seqable within the same runtime >> >> session. > > Problem for who? Problem how? Extending seqable? to types you do not control > or which are not seqable? as defined by Clojure itself is asking for trouble > anyhow.
If you extend it further at all, it could happen that it gets called on a non-array object of a type before being extended to that type, though this is much more likely at a REPL than in deployment at least. On the other hand if you won't ever extend it further at all there's no real advantage over a non-protocol solution, like the monolithic (or ...)-bodied function punting to a memoized is-array-class? function to check for the array case. -- 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
