Clojure Programming/Examples/API Examples/Reference Tools

ref

See ref-set for more.

user=> (def cross-thread-mutable (ref {}))
#'user/cross-thread-mutable
user=> cross-thread-mutable
#<Ref clojure.lang.Ref@1a5f739>
user=>

ref-set

user=> (def foo (ref 0)) 
#'user/foo 
user=> foo 
#<Ref clojure.lang.Ref@7c2479a4> 
user=> @foo 
0 
user=> (ref-set foo 1) 
java.lang.IllegalStateException: No transaction running (NO_SOURCE_FILE:0) 
user=> (dosync (ref-set foo 1)) 
1 
user=> @foo 
1 

@

(deref (ref 5))
@(ref 5)
@(atom 5)
(with-local-vars [x 5] @x)
@(agent 5)

force

(def df (delay (println "hello")))
(println "world")
--> world
(force df)
--> hello

commute

(def employee-records (ref #{}))
(dosync (commute employee-records conj "employee"))