The first thing which comes to my mind is how the Javascript interpreter works, using a regex to replace the deepest s-expressions by their evaluations (both s

The first thing which comes to my mind is how the Javascript interpreter works, using a regex to replace the deepest s-expressions by their evaluations (both scary and brilliant)[0] I found the console[1] and started using it. I was trying to expand a list of things into LI elements; at some point I wrote this: {def lis| {lambda {:x} {li :x}}} The bar represents the cursor just before I hit backspace. After I hit backspace, I entered an infinite recursive evaluation which eventually stopped with stack overflow. Maybe evaluating the code after each keypress is not ideal. Or maybe you could add a timeout, a custom depth limit or something else ;-) Also, being accustomized to syntax coloring, completion, indentation, warnings, etc., I find the environment particularly dry, especially when you consider your target audience. On the one hand, beginners who want to learn will be able to explore and find their way through trial and errors anyway, but on the other hand, a little bit of feedback can help when they are blocked. For example, when forms are badly formed the output is "ooops": this is better than nothing, obviously, but still a little terse. I looked at the teaching[2] section and this is a good introduction, and I am not telling you to be more like Scratch either, but there might some way to bring a little bit more interactive help. Overall, this is a nice project and it brings a lot of different things together (maths, svg, javascript). I could be useful as a richer Markdown and I find it more readable than the typical Wiki syntax. [0] http://epsilonwiki.free.fr/alphawiki_2/meca/JS.js http://epsilonwiki.free.fr/alphawiki_2/meca/JS.js [1] http://epsilonwiki.free.fr/lambdaway/meca/ http://epsilonwiki.free.fr/lambdaway/meca/ [2] http://epsilonwiki.free.fr/lambdaway/?view=teaching http://epsilonwiki.free.fr/lambdaway/?view=teaching