KLIPSE is a clojure[script] web REPL built on top of self-host clojurescript.

In this article, we describe how to tweak KLIPSE.

URL parameters

KLIPSE configuration is done with the url parameters:

  • cljs_in=<cljs_code> - initial content of the clojurescript box ( code must be encoded properly)
  • cljs_in.gist=<gist_id> - load code from a gist; e.g. http://app.klipse.tech?cljs_in.gist=viebel/368d3bec58d3ec47e935ad488bafb600&eval_only=1
  • container=1 - container more useful for UI stuff: instead of the compilation box, you have your klipse container
  • js_only=1 - display only input and js boxes
  • eval_only=1 - display only input, eval and print boxes
  • static-fns=true - eval and transpile js code with static dispatch
  • external-libs - array of external libs to resolve the namespace dependencies. Here is an example with the gadjett library. Each lib name must me wrapped in double quotes.
  • verbose - (default false) passed to bootstraped eval and compile functions as :verbose opts
  • cache-buster - (default false) when true the namespaces are loaded with a cache buster
  • max-eval-duration - (default 1000) max number of 1000 seconds the code is allowed to run synchronously before being interrupted.
  • compile-display-guard: (default false) when true, display the anti-starvation code inside result of compilation
  • print-length: (default 1000) max number of items in collections to display - useful to prevent browser stuck when evaluating infinite sequences like (range)
  • beautify-strings: (default false) when evaluation result is a string - display the “interior” of the string without escaping the quotes.


Interaction with the REPL is done with hotkeys:

  • Ctrl-Enter or Cmd-Enter - eval and transpile
  • Ctrl-S - display in the console and alert box shareable url that embeds the content of your current KLIPSE session.
  • Ctrl-R - reload the app with the same content (pass the content to cljs_in url parameter).