while-let

Repeatedly executes body while test expression is true, evaluating the body with binding-form bound to the value of test.

I've found this particularly useful with core.async, where you want to loop until a channel is closed (and it returns nil).

Installation

In your project.clj add:

Usage

(while-let bindings & body)

Simple example

Pop each item off the front of a vector and print it out.

(let [data (atom [1 2 3 4 5])]
          (while-let [item (first @data)]
                     (println "item: " item)
                     (swap! data rest)))

Core.async example:

Take from a channel until it gets closed (a closed channel will return nil), or the channel returns false

(go (while-let [data (<! (channel))]
               (println data)))

License

Copyright © 2014 Mark Mandel

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.