;Hmmmm but wait, I saw on the website that Clojure does have local variables! user=> (with-local-vars [a 2] (var-set a 3) (var-get a)) 3
;I am allowed to close over them: user=> (def f (with-local-vars [a 2] #(+ 1 (var-get a)))) #=(var user/f) ;But they stop me to shoot myself user=> (f) java.lang.IllegalStateException: Var null is unbound. (NO_SOURCE_FILE: 0) "Executes the exprs in a context in which the symbols are bound to vars with per-thread bindings to the init-exprs. The symbols refer to the var objects themselves, and must be accessed with var-get and var- set" ;The protection from leaky concurrent mutation is at execution ;Where as an intentional closure sensibly uses a ref (let [secret (ref "nothing")] (defn read-secret [] @secret) (defn write-secret [s] (dosync (ref-set secret s)))) #=(var user/write-secret) user=> secret java.lang.Exception: Unable to resolve symbol: secret in this context user=> (read-secret) "nothing" user=> (write-secret "hi") "hi" user=> (read-secret) "hi" So it seems Clojure doesn't force you to avoid using imperative style variable, it is just not widely advertised that they exist :) --~--~---------~--~----~------------~-------~--~----~ 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 To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
