BTW, to be clear: You misuse the term "Untyped" in your example. Both methods are fully typed. They just use different types. This is kind of relevant, because you say "typed is better" - but both are typed to the same degree.
On Sun, Jun 27, 2021 at 8:55 PM Axel Wagner <axel.wagner...@googlemail.com> wrote: > On Sun, Jun 27, 2021 at 8:17 PM Victor Giordano <vitucho3...@gmail.com> > wrote: > >> But but but... just bear with me... cuz, in this specific case, I guess >> you could employ both "approaches". See my example here >> <https://play.golang.org/p/f2NOTHjffCm>. >> > > Yes, I'm aware this works. That wasn't in doubt. The question is "is it > better". In my opinion, it isn't. > > >> Also I feel the need to clarify something about I stated... >> > Thanks to all for the answer, i really try to see any actual reason but >> i still don't get it. For me, to my humble acknowledgement, if I define a >> type I tend to use everywhere it appears. Period. End of the story. >> I have to admit, although I follow this recipe as a compass, I may pass >> by sometimes and leave redundant definitions. It is okay, after all, we are >> humans and errors happen. >> >> El dom, 27 jun 2021 a las 13:28, Axel Wagner (< >> axel.wagner...@googlemail.com>) escribió: >> >>> On Sun, Jun 27, 2021 at 6:05 PM Victor Giordano <vitucho3...@gmail.com> >>> wrote: >>> >>>> Thanks to all for the answer, i really try to see any actual reason but >>>> i still don't get it. For me, to my humble acknowledgement, if I define a >>>> type I tend to use everywhere it appears. Period. End of the story. >>>> >>> >>>> > FWIW, arguing that `http.HandleFunc` should take a `http.HandlerFunc` >>>> because there exists a defined type with the same underlying type as the >>>> parameter is a bit like arguing every function that takes an `int64` should >>>> instead take a time.Duration <https://golang.org/pkg/time/#Duration>. >>>> >>>> Allow me to put in different words: if you define `func >>>> doSomething(duration int64)` at least i will argue why don't employ >>>> time.Duration <https://golang.org/pkg/time/#Duration> as a type there, >>>> if the parameter actually represents a Duration that is also a defined >>>> type, ¿you don't?. >>>> >>> >>> Yes. But that's the thing - if what the function actually takes a >>> duration, then the correct type is a duration. But the type >>> `http.HandleFunc` takes is *not* a `http.HandlerFunc`, it's a >>> `func(http.ResponseWriter, *http.Request)`. It's a different type and it's >>> the correct type to describe what that function is for. If the type was >>> `http.HandlerFunc`, then `http.HandleFunc` wouldn't need to exist, because >>> `http.Handle` would suffice. >>> >>> For example, if you had a function >>> >>> // DurationFromMS returns a time.Duration, based on a duration given as >>> an integer in ms. >>> func DurationFromMS(d int64) time.Duration { >>> return time.Duration(d * 1000) >>> } >>> >>> Would you make the parameter type `time.Duration`? After all, it >>> represents a duration, right? But you wouldn't. It would be the wrong type >>> to represent what the function does. >>> >>> Or, a different example: We could introduce a new type in the `filepath` >>> package: >>> >>> // Path is a path, using the OS-specific delimiter >>> type Path string >>> >>> // Verify makes sure that p is a path, using the correct, OS-specific >>> delimiter. >>> // It returns p as a Path, and an error, if p was invalid. >>> func Verify(p string) (Path, error) >>> >>> We could then have `filepath.Join` etc. take `Path`s, instead of >>> `string`s, to represent that the argument actually must be a valid path, >>> using the OS-specific separator. Which would be different from `path.Path`, >>> of course, which would always use "/" as a separator. Meaning you wouldn't >>> be able to accidentally use one as the other, which would add type-safety. >>> >>> But should `Verify` take a `Path` here? Of course not. That would be the >>> wrong type. It just returns its argument converted into the correct type, >>> but semantically, it still takes *a plain string*. Before you pass the path >>> into `Verify`, it doesn't have the semantic association of "this string is >>> an OS-specific path" - that's exactly the semantic association that >>> `Verify` creates. >>> >>> Your argument hinges on the assumption that `http.HandleFunc`s parameter >>> has the semantic interpretation (not only the same underlying type as) as >>> `http.HandlerFunc`. But it doesn't. The semantic interpretation of the >>> argument to `http.HandleFunc` is a plain function. Otherwise, it wouldn't >>> need to exist - because we already *have* a function that can take a >>> `http.HandlerFunc`: `http.Handle`. >>> >>> The plain func is describing *exactly* the type that function should >>> take. `http.HandlerFunc` would be the wrong type. >>> >>> >>>> I won't say the same about other things that hold an int64 that >>>> represents for example an ID of record in a database. >>>> >>>> >>>> >>>> El dom, 27 jun 2021 a las 12:56, 'Axel Wagner' via golang-nuts (< >>>> golang-nuts@googlegroups.com>) escribió: >>>> >>>>> FWIW, arguing that `http.HandleFunc` should take a `http.HandlerFunc` >>>>> because there exists a defined type with the same underlying type as the >>>>> parameter is a bit like arguing every function that takes an `int64` >>>>> should >>>>> instead take a time.Duration <https://golang.org/pkg/time/#Duration>. >>>>> That's just not how types tend to work. >>>>> >>>>> It makes no sense for `http.HandleFunc` to take a `http.HandlerFunc`, >>>>> because it's purpose is specifically to work on a plain function. If you >>>>> have an `http.HandlerFunc`, you can already just call `http.Handle` - >>>>> there >>>>> is no need to make a separate function that takes a *specific* >>>>> implementation of `http.Handler`. >>>>> >>>>> On Sun, Jun 27, 2021 at 5:51 PM Axel Wagner < >>>>> axel.wagner...@googlemail.com> wrote: >>>>> >>>>>> 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 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/CAEkBMfHiQP0WEbGPrFkY5gSzaaiQ5OqisySiy8_yUdfVAE-v6w%40mail.gmail.com >>>>> <https://groups.google.com/d/msgid/golang-nuts/CAEkBMfHiQP0WEbGPrFkY5gSzaaiQ5OqisySiy8_yUdfVAE-v6w%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> >>>> >>>> -- >>>> V >>>> >>> >> >> -- >> V >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. 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