clojurescript

I've been looking around for how to create animations in Om, I've tried creating a RaphaelJs component with moderate success. I get the animation I want, but for some reason Om renders multiple instances of the SVG element. Looking at the animation example in the Om github folder uses setInterval to change the values you want to animate, which is less than ideal. I'm aware of the CSSTransitionGroup addon, but it looks like you can only flip between preset animations defined in the CSS, you can't decide to do something like rendering a path and having a shape following it with randomised

I must be missing something very obvious here but I'm trying to setup a very basic program to put an item onto a channel then block until I can take it off again. The entire program is below: (ns shopping-2.core (:require [cljs.core.async :as async :refer [>!! <!! put! chan <! close! <!!]])) (let [c (chan)] (>!! c "hello") (.write js/document (<!! c)) (close! c)) The JavaScript error I'm getting is: Uncaught TypeError: Cannot call method 'call' of undefined I had that error before when I forgot to :refer chan in (if I just open the channel, then close it again the program runs fine) However

(defn string-to-string [s1] {:pre [(string? s1)] :post [(string? %)]} s1) I like :pre and :post conditions, they allow me to figure out when I have put "square pegs in round holes" more quickly. Perhaps it is wrong, but I like using them as a sort of poor mans type checker. This isn't philosophy though, this is a simple question. It seems in the above code that I should easily be able to determine that s1 is a function argument in the :pre condition. Similarily, % in the :post condition is always the function return value. What I would like is to print the value of s1 or % when either of these