On Sun, Jun 27, 2021 at 5:25 PM Victor Giordano <vitucho3...@gmail.com> wrote:
> I keep wondering if they code that way for any reason. With "code that > way" I mean: define a type and then not use it. > As I said: It's used plenty of times. Both inside of `net/http` and outside of it. > > - So, ¿why not employ the type defined in the first place? > > I feel like I gave a bunch of reasons for this too. > Don't get me wrong,but if I define a type I tend to use that type where it > appears. That is in fact the basis of making types, to use them. So that > feeds my questioning! > > > El dom, 27 jun 2021 a las 11:46, 'Axel Wagner' via golang-nuts (< > golang-nuts@googlegroups.com>) escribió: > >> If I understand you correctly, you are suggesting to replace the >> parameter type `func(http.ResponseWriter, *http.Request)` with the >> parameter type `http.HandlerFunc`. You've been (correctly) told that we >> can't make that change, because it would break the Go 1 compatibility >> change (as there is code which currently compiles which wouldn't compile >> after that change). But you are wondering if, *ignoring* the compatibility >> guarantee, it would be a good change. Am I getting this right? >> >> If so: I don't think it would be a good change. >> >> First, it's important to realize that the *only* reason, >> `http.HandlerFunc` exists at all, is so that you can write a >> `func(http.ResponseWriter, *http.Request)` and use it as a `http.Handler`, >> in the places where `net/http` expects the latter. You say the type isn't >> used - but it is. It's used by *users* of the `net/http` package, to make >> their plain functions into `http.Handler`s. It is also used in `net/http` >> itself - in the exact function you are referring to >> <https://golang.org/src/net/http/server.go?s=77627:77714#L2487>. That is >> the exact and only purpose of that type, to make a plain function implement >> the `Handler` interface. So, taking a plain function as a parameter *is the >> purpose of having the `HandlerFunc` type*. >> >> You also say that adding types is a good thing. I tend to disagree with >> that as a general statement. Adding types is a good thing, if it serves as >> important documentation or if it serves to catch bugs. I don't think either >> of these would be happening with this change. In terms of documentation - >> well, you don't *have* to pass a `http.HandlerFunc`, so there is no reason >> for the documentation to make it clear that you should. You can (and >> should) just pass a plain `func`. So, using the defined type here wouldn't >> serve as documentation, it would document the *wrong* thing. >> >> As for catching bugs: Making the parameter type a defined type would only >> change one thing in terms of type-safety. It would mean that if you define >> a *different* type `type MyFunc func(http.ResponseWriter, *http.Request)`, >> the compiler would prevent you from writing `http.HandleFunc(…, >> MyFunc(f))`. Preventing a bug would thus require that your `MyFunc` type >> would have to be used semantically differently from `http.HandlerFunc`. But >> that seems *exceedingly* unlikely, given that you defined `MyFunc` in terms >> of the `net/http` package. And it would then appear *exceedingly* unlikely, >> that you'd accidentally mix the two up - almost all usages of >> `http.HandleFunc` will pass the name of some defined function and that will >> always work. >> >> But all of this discussion is really moot. It's a breaking change, so it >> can't happen - whether it's a good change or not doesn't exactly matter at >> that point. Personally, *if* we could "go back in time" and wouldn't have >> to worry about backwards compatibility, my vote would rather be to change >> the language to make the HandlerFunc type obsolete >> <https://github.com/golang/go/issues/21670> and remove it altogether. >> >> On Sun, Jun 27, 2021 at 3:53 PM Victor Giordano <vitucho3...@gmail.com> >> wrote: >> >>> Hello gophers! >>> >>> While studing at this source code >>> <https://github.com/golang/go/blob/37f9a8f69d6299783eac8848d87e27eb563500ac/src/net/http/server.go> >>> in search for some knowledge and enlightment, i do note that in some file a >>> type is defined and then is not used in a place where it could be used. >>> This open an interrogant for me, because tipification is often good thing, >>> regardless the language I may state, and I express it via a ticket >>> <https://github.com/golang/go/issues/46926>. I get the idea that due to >>> language grammar changing the code would be a breaking change. >>> >>> But i keep wondering if they actually do this for a reason.. i mean, >>> given the possiblity to get back in time, ¿does the team at golang will >>> write the same source code, definiting a type with a name and then >>> intenttionally not using it? i mean...i keep wondering if there is any >>> reason for defined types and then not use it and using the gitlab channel i >>> probably fail to express my initial intention. I do often read some third >>> party code, in order to view others minds (or try at least..), what i'm >>> asking here is a question in order to get another people point of view. >>> >>> Thanks again! >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "golang-nuts" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to golang-nuts+unsubscr...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/golang-nuts/96369719-6200-4765-aee1-83befce04666n%40googlegroups.com >>> <https://groups.google.com/d/msgid/golang-nuts/96369719-6200-4765-aee1-83befce04666n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "golang-nuts" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/golang-nuts/VBQrlI6-zW0/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> golang-nuts+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/CAEkBMfHnCTf_4G5ZhGX0EXBKJRN9LcEWbKWOdPiCTKdX6SDqPA%40mail.gmail.com >> <https://groups.google.com/d/msgid/golang-nuts/CAEkBMfHnCTf_4G5ZhGX0EXBKJRN9LcEWbKWOdPiCTKdX6SDqPA%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > > > -- > V > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. 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