[benth]

So there is lexical scope, but it requires "do" which means an extra function, something that wasn't required in JS. You don't get lexical scope "for free" in CoffeeScript, there's overhead, unlike in JS. Is that right?

[raganwald]

Yes, and that is a concern I share:

https://github.com/jashkenas/coffee-script/issues/2552

Scheme interpreters have been optimizing away the cost for most cases since the 1970s.

[mchahn]

I use `var x;` which transpiles exactly to var x; so there is no overhead. The backtick in CS lets JS pass through.