Re coffeescript and shadowing: I don't like it because I dislike the mismatch in semantics with JavaScript and am used to Python, but beyond that, I'm not sure

Re coffeescript and shadowing: I don't like it because I dislike the mismatch in semantics with JavaScript and am used to Python, but beyond that, I'm not sure it's wrong. Re set: it would slightly complicate your grammar, but I don't think detecting "word space* = ..." would create any ambiguities. Partially this issue is just about how much you value explicitness/regularity vs. concision.