Are you actually claiming that "#" is a computer science convention for comments? It's not used in C, C++, Fortran, Lua, or many other languages. For example, comments in OCaml are ( * ... * ) (I've put extra spaces to thwart HN's formatting.

Language using "--" for comments include Lua and Haskell.

You've made me curious - what languages to you use/know that make you think "#" is a "CS convention" for comments?

EDIT: Found a reference:

http://en.wikipedia.org/wiki/Comparison_of_programming_langu...

Further edit: In response to the clarification that CS meant CoffeeScript and not Computer Science (nor the riot control gas), the point, I guess, then follows other commentators, who observe that Lua, to which this compiles, uses "--".