Comment by zem

you can view it as serving the same role as universal function call syntax, the latter being a feature in some other languages that rewrites `a.f(x)` to `f(a, x)` if `a` doesn't have a method `f`. in ruby you can just add the method to `a`'s class directly, but the idea is the same - you're adding some user defined function that is closely related to the type of `a`, and you're using method call syntax because that reads nicely.