On Dec 12, 12:36 am, Ken Wesson <kwess...@gmail.com> wrote:
>
> You can "change" the metadata on the object held by the atom (if that
> object supports metadata) via (swap! a with-meta ...).
>
> One thing a bit annoying is if you want to alter the metadata in an
> incremental way. To do that atomically requires a closure. Or defining
> a swap-meta! function, like so:
>
> (defn swap-meta! [a f & args]
>   (swap! a
>     (fn [x]
>       (with-meta x (apply f (meta x) args)))))

I still very often mix up the state and identity in Clojure. What I
tried to do is to add metadata to the atom itself, not to the value it
holds. Now I see that it was kind of stupid:).
Your swap-meta! function is of great use, from now on I will use in
such cases. Thank you!
Your swap-meta!

-- 
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

Reply via email to