Closures
Next we’ll look at functions that return other functions as a result. One use for such functions is to provide behavior that is facilitated by constructors in object-oriented languages. For example, if you want to initialize some variables before using a function, you can do so as follows:
| | (defn make-client [url] |
| | (fn [request] (str "sending " request " to " url))) |
| | (let [client (make-client "http://foo.org")] |
| | (println (client "request 1")) |
| | (println (client "request 2"))) |
Here we create a function that accepts a url parameter and returns a function that accepts a request as its parameter. The inner function has access to the url variable since it’s defined in the same scope.
This type of function is called ...
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