I'm a big fan of Idyll, especially how easy it is to get started with. Here's a screenshot of something I made not more than 20 minutes after first seeing it [1].

Also, can I put in a plug for nearley [2], the parsing library that Idyll uses? The Idyll parser is here [3].

[1] https://imgur.com/a/5I143

[2] http://nearley.js.org

[3] https://github.com/idyll-lang/idyll/blob/master/packages/idy...