> particularly in Go where everyone crams everything into single-func interfaces which are almost exclusively far worse Depending on scope, I've grown to prefe

> particularly in Go where everyone crams everything into single-func interfaces which are almost exclusively far worse Depending on scope, I've grown to prefer the single func interface. For a smaller scope use, say filepath.Walk, absolutely, pass in a closure, good stuff. For larger stuff, like say a chain of http middleware and handlers, I think it can be very limiting. you get a big benefit from using the interface over a function: the underlying type _can_ have more methods and implement. this gives room to implement a parallel interface, for example, to collect all possible routes, or to trace what handlers a request would pass through. I don't think there's a one-size-fits all approach, use whatever gives the effort:utility tradeoff you're looking for.