On 8 December 2014 at 17:54, Andy L <core.as...@gmail.com> wrote:
>> But I'd personally just use a delay rather than "locking" for this
>> purpose.
>
>
> It is not that I like locking at all. However I still fail to see, how in a
> multithreaded context memoize/cache prevents executing a given function more
> than once (which I want to avoid at any cost here) since cache lookup and
> swap! does not seem to be atomic :
> https://github.com/clojure/core.cache/blob/master/src/main/clojure/clojure/core/cache.clj#L52

When you say

  (delay (foo)),

foo will be called at most once, regardless of how many times you
deref (@) / force the delay. (If you never force the delay, it will
not be called at all.) The way this is enforced is through making
deref a synchronized method on delays.

Cheers,
Michał

-- 
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
--- 
You received this message because you are subscribed to the Google Groups 
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to