luciano/clojure-koans
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Use let scope to bing the agent

Browse source
This commit is contained in:
Ignacy Moryc 2012-09-23 15:38:31 +02:00
parent 00385eee11
commit c8f711e209
1 changed files with 25 additions and 24 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

49
src/koans/21_agents.clj
View file

@ -1,31 +1,32 @@
(def agent-example
"Agents provide shared access to mutable state."
(agent 10))
(meditations (meditations
"Creating an Agent is as simple as assigning it a value" (let [agent-example (agent 10)]
(= __ (instance? clojure.lang.Agent agent-example))
"To get agent's value you dereference it" "Creating an Agent is as simple as assigning it a value"
(= __ @agent-example) (= __ (instance? clojure.lang.Agent agent-example))
"To change agent's value you use send function - you pass action and action's arguments to it. "To get agent's value you dereference it"
(= __ @agent-example)
"To change agent's value you use send function - you pass action and action's arguments to it.
Send function, returns immediately, but the action is prccessed in a separate thread and it's the result, Send function, returns immediately, but the action is prccessed in a separate thread and it's the result,
of that action that gets assigned to agent's state" of that action that gets assigned to agent's state"
(= __ (do (= __ (do
(send agent-example + 2) (send agent-example + 2)
@agent-example)) @agent-example))
"You can't just send a value to agent" "You can't just send a value to agent"
(= __ (do (= __ (do
(set-error-mode! agent-example :continue) (set-error-mode! agent-example :continue)
(send agent-example 20) (send agent-example 20)
@agent-example)) @agent-example))
"You can create validations for states that agent is allowed to take" "You can create validations for states that agent is allowed to take"
(= __ (do (= __ (do
(set-validator! agent-example #(even? %)) (set-validator! agent-example #(even? %))
(try (try
(send agent-example + 1) (send agent-example + 1)
(catch IllegalStateException e)) (catch IllegalStateException e))
@agent-example))) @agent-example))
"It's a good idea to clean up any not finished agents after you are done"
(shutdown-agents)))