I didn’t mention the proposal of := because it’s not happening until Julia 2.0. I wanted to see what we can do with what we have at hand, so documentation becomes important. I do agree that it would allow us to distinguish between declaration ( let x, local x, f(x) = ...), definition :=, and assignment =, which is at the source of a lot of confusion. But we should be prepared to see code that looks like f(x:=0) := nothing if we are going to use := consistently.