On Sun, Oct 4, 2009 at 4:26 PM, Stephen C. Gilardi <squee...@mac.com> wrote: > > On Oct 4, 2009, at 5:04 PM, Mark Volkmann wrote: > >> Minor technicality ... Vars are a reference type, but deref and @ don't >> work with them. > > I'm guessing you're thinking of an interaction like this: > > user=> (def a 3) > #'user/a > user=> @a > java.lang.ClassCastException: java.lang.Integer cannot be cast to > clojure.lang.IDeref (NO_SOURCE_FILE:0)
Yes, that's what I was thinking about. > However, it's important to remember that the expression "a" does not > evaluate to the Var named "a". The Var named by "a" can be accessed via (var > a) or #'a. > > deref does work with Vars: > > user=> @(var a) > 3 > user=> @#'a > 3 > user=> > > deref works with objects that implement clojure.lang.IDeref and > clojure.lang.Var is among them: > > user=> (isa? clojure.lang.Var clojure.lang.IDeref) > true > user=> Thanks for clarifying that! -- R. Mark Volkmann Object Computing, Inc. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
