I'm sure there is an equally reasonable explanation of costs and implications for your example. There sure is. Had I defined a method (like you suggested), and

I'm sure there is an equally reasonable explanation of costs and implications for your example. There sure is. Had I defined a method (like you suggested), and just gone ahead and made my function variable point to that, the compiler would have enough information to infer types. In that case I would get away with the following: var someFunction = (X) => entropy(X); Just felt like contributing somethings which isn't on the HN daily list of languages, that's all :)