For anyone interested in making little games in Golang, Termloop[1] is a terminal-based engine (though it uses text to render rather than this iTerm-specific feature).
The idea of supplying a spec to transform arbitrary data is interesting to me. I did one in JavaScript called Reshaper[1], and then hooked it up to a library wrapper called Smolder[2].
The result was a sort of system whereby data going into a function would be automatically 'reshaped'. It worked well as a proof-of-concept, but obviously was too fragile for most uses (though it's used in the automatic graphs in Kajero[3]).
The difference here seems to be that the spec defines the actual transformations, rather than just the desired final structure.
Yup, Tonic is super cool. This is more for presenting data than demoing libraries, but I'd like it to be as useful as possible for many things.
If you save it as an HTML file you can obviously add your own client-side JS. Node packages are a ways off right now though - would need to think about how to do it as it's all client-side.
I looked into Babel but the standalone package is (comparatively) massive. Could be an optional extension, possibly.
I think it has potential for use as a way to write documentation for JS libraries, so being able to use arbitrary packages is certainly something I'd like to add. :)