Programming Enchiladas

A ClojureScript-based HTML5 Canvas and SVG Graphics Playground, much like http://bl.ocks.org/ but specifically designed for showcasing small ClojuresScript code demos: The underlying agenda is to show how small simple functional programs can generate complex behaviour.

I was getting sick of setting up yet another lein/noir for every new folly, so it made more sense to have a framework which loads public ClojureScript gists directly from github, compiles them on the fly and serves them out.

This allows shared/social and version-tracked editable ClojureScripts to be run by anyone anywhere with a reasonably modern browser (tested in Chrome/FF/Safari). In order to compile and run any .cljs files in gist https://gist.github.com/rm-hull/5278162 (for example), go to http://programming-enchiladas.destructuring-bind.org/rm-hull/5278162 - see below for more examples.

As part of the available 'stack' (for want of a better word), the following client-side clojureScript bindings are available:

Function	Notes
enchilada/canvas	A canvas object, which you can resize, move, whatever.
enchilada/ctx	The graphics context, on to which you draw your stuff.
enchilada/svg	An SVG object, on to which you insert DOM stuff (initially hidden).
enchilada/proxy-request	Returns a URL which will be proxied through self.
turtle.*	https://github.com/rm-hull/turtle graphics library
dommy.template/*	Templating based on Clojure's Hiccup html templating library.
monet.*	All the https://github.com/rm-hull/monet canvas drawing functions.
jayq.*	https://github.com/ibdknox/jayq jQuery bindings.
c2.*	Kerninglabs C2 data visualization library.
vomnibus.*	https://github.com/lynaghk/vomnibus bindings.
cljs.core.logic/*	MiniKanren implementation.
cljs.core.async/*	Communicating sequential processes implementation.
tailrecursion.priority-map/*	Clojurescript implementation of data.priority-map

The following javascript libraries are loaded and available:

http://jquery.com/ v2.0.1
http://arborjs.org/ v0.9.2
http://www.senchalabs.org/philogl/ v1.5.2

NOTE: This software is definitely alpha work-in-progress, please treat as such.

Examples

Prerequisites

You will need Leiningen 2.1.2 or above installed.

Running

To start a web server for the application, run:

$ lein ring server

This will start the server at port 3000 or thereabouts. Then create your ClojureScript gist, and slot in the login and id, and hack on.

Optional: If a connection to a MongoDB database is supplied via config variable MONGODB_URL as below (substitute values for user, password, host and db as appropriate), then minimal usage stats will be written out for gamification purposes:

$ export MONGODB_URL=mongodb://user:password@host:10046/db

If using heroku, add a config param:

$ heroku config:add MONGODB_URL=mongodb://user:password@host:10046/db

Optional: By default, Github aggressively throttles requests if requests are anonymous (60 requests per hour); Set GITHUB_OAUTH_TOKEN to a generated authentication token to increase the rate limit to 5000 requests per hour:

$ export GITHUB_OAUTH_TOKEN=xxxxxxxxxxxxxxxxxxxxxxxxxxx

$ heroku config:add GITHUB_OAUTH_TOKEN=xxxxxxxxxxxxxxxxxxxxxxxxxxx

(See application note on authorizing 3rd party access to github here: http://developer.github.com/v3/oauth/#create-a-new-authorization)

Troubleshooting

Q. Why doesn't my clojurescript compile, it looks ok?

A1. Did you include a namespace? e.g. (ns example)

A2. Did you name it with a .cljs extension?

NEW! Now supports source maps

Clojurescript debugging/line-stepping in Chrome is now supported. And it works really well! :)

TODO

~~UI -> home page (carousel of recently viewed, most viewed, rated, etc)~~
UI -> allow in-page editing
~~Stats / tracking~~
More examples
Documentation
~~Stop using local storage - using Heroku's ephemeral FS not so good for permanent storage (github, Amazon S3 instead?)~~
~~Sitemap based on mongo-db rather than Heroku's ephemeral FS.~~
Automatic screenshot capability with https://github.com/ariya/phantomjs/wiki/Screen-Capture
~~Add CORS headers to proxy~~
~~Implement simple big-bang (http://docs.racket-lang.org/teachpack/2htdpuniverse.html#(form._world._((lib._2htdp/universe..rkt)._big-bang)))~~

Known Bugs

~~Routing does not support private gists properly~~ FIXED: 21/12/2013
Arbor/PhiloGL externs don't work properly - must be compiled with no optimization
Capture all error scenarios (inc. Google closure warnings and errors & trap javascript errors)