Is moderated livestock grazing an effective countermeasure for desertification? If a creature's best food source was 4,000 feet above it, and only rarely fell from that height, how would it evolve to eat that food? Update the question so it can be answered with facts and citations by editing this post. Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. Connect and share knowledge within a single location that is structured and easy to search. @p1gd0g there really is no problem in keeping state with function types: @zerkms Technically true, but not very useful way of looking at it. Why can't I define a static method in a Java interface? @zerkms: If that interpretation is correct, then the question is off-topic as opinion based. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Makes sense, thanks for clarifying that out! Is there a way to have an indicator referring to the interface that a function implements and to see where an interface is implemented? So we need to create a type that matches the function signature, and provides the interface methods. Say, a string: But if you want to just implement the function directly, as with: This doesn't satisfy the interface. I was reading that, in Go, functions can implement interfaces (like in this example or this example). In the US, how do we make tax withholding less if we lost our job for a few months? Can a human colony be self-sustaining without sunlight using mushrooms? I've never made one, but I'd be 100% done for it! Using an interface for "duck typing" just fits with the Go way of doing things. Does anyone know if there's an extension for that in VS Code? The reason to attach a method to a function type is therefore to satisfy an interface. But what value is there in having a function implement an interface? Give feedback. Want to improve this question? Was this translation helpful? Why had climate change not been proven beyond doubt for so long? It's idiomatic. Interfaces are easier to work with, because they can be easily expanded/embedded. Set a default parameter value for a JavaScript function. That is, I could implement a struct that satisfies both the. Maybe that's a bit of a tautology, since the reason it fits with Go is becuase it's done this way. map function for objects (instead of arrays). setup loops; never enters loop - restarting? One of the thing that I haven't found how to do yet is VS Code that is possible to do in GoLand is to have an indicator next to a function that implements an interface method that refers to the implemented interface as such: Also having an indicator in the interface itself that refers to implementation of that same interface. That's what http.HandlerFunc does: If the question is: Why did the authors of the standard library decide to make ServerHTTP an interface, rather than a function type, without searching old mailing list archives for clues, only speculation is possible, which is really off-topic here, but here's a small stab at it: As a thought experiment, just imagine if the io.Reader interface where instead a function type: I think it's pretty easy to see that madness would ensue all over the place. What value is there in this? I decided to make the switch from GoLand to VS Code and I'm liking it a lot so far.

If you ever have a complex handler, which maybe tracks its own state, using a struct is the natural solution, and exposing it as an interface is more natural than a closure (which would be required if this were implemented as a function type). rev2022.7.21.42639. Interface defining a constructor signature? Nevertheless, +1d as this is a good answer given the question is not fully clear :-), Why would you implement an interface on a function in Go? Announcing the Stacks Editor Beta release! You signed in with another tab or window. Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, Single function interface vs a function type are just a preference, I don't see any. If you run "Find All Implementations" from a method, vscode will show the list of corresponding interfaces. Why did the gate before Minas Tirith break so very easily? If it doesn't exist, does anyone know if it'd be difficult to make an extension for that? Just think about your second cited link, the "counter" handler. Let's look at the http.Handler interface, since you brought that up. var functionName = function() {} vs function functionName() {}. What drives the appeal and nostalgia of Margaret Thatcher within UK Conservative Party? Grep excluding line that ends in 0, but not 10, 100 etc, Text in table not staying left aligned when I use the set length command. I know it's possible to go to implementations from the interface when you right click it -> Go to implementations and from the interface implementation it works as well, but having an indicator is super useful because you see it right away. Is there a political faction in Russia publicly advocating for an immediate ceasefire? But in this case I agree yes. Show that involves a character cloning his colleagues and making them into videogame characters? What are the purpose of the extra diodes in this peak detector circuit (LM1815)? What is the difference between an interface and abstract class? For me, a handler could have own states.

Beta Short story about the creation of a spell that creates a copy of a specific woman. Such a design covers that case. If you run "Find All Implementations" from the struct type, vscode will show the list of interfaces the type implements. Scientifically plausible way to sink a landmass. Can anyone Identify the make, model and year of this car? Their question was more about: why the Go core team developed a single function interface instead of just a function type. [closed], Learn more about Collectives on Stack Overflow, Design patterns for asynchronous API communication. Find centralized, trusted content and collaborate around the technologies you use most. It would work likewise. Why does hashing a password result in different hashes, each time? How should we do boxplots with small samples? Not necessarily: there might be some technical aspects that make one option better than the other which OP don't know. For example, why take the time to define an interface, a new type for the function, and a method, like this: when instead you could just create a single function like this: A single function (in your example, func ServeHTTP, doesn't satisfy any interfaces. What does the exclamation mark do before the function? You can implement this interface with, for example, a struct: You could also satisfy it with some simpler type. What about expressing intent, readability, decoupling and easier to extend at a later time to name a few reasons interfaces and a single function type are not in any way equivalent. I don't see how you can think that your two examples are in any way equivalent. The same value in having any other type implement an interface. This is not very intuitive but it looks like this was an attempt to fit Go-specific information in the general purpose LSP concept back then. The point of using an interface is that you can re-use that same interface with any type that satisfies it's requirements. golang/go#35550.