Ok. Thanks for the insight again. Correction noted. I do get that types are named or not, and any not named type is a type of its own; and two not named types are different despite having the same definition (like in Pascal)
Nice to clarify the issue. Now regarding our friendly discussion... > The question is "is it better". In my opinion, it isn't. mmmm my inner philosophical orc is wandering... 🤔... it's not my source code, what I can say... I will probably try to employ an unique type where possible, or the least quantity of types. At least that is what I tried in my source code. El dom, 27 jun 2021 a las 16:08, 'Axel Wagner' via golang-nuts (< golang-nuts@googlegroups.com>) escribió: > 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 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/CAEkBMfFDgoq0OrR%3DDPgW9h4tGAmLXqO%3DQ52_kddgbctwORhGDw%40mail.gmail.com > <https://groups.google.com/d/msgid/golang-nuts/CAEkBMfFDgoq0OrR%3DDPgW9h4tGAmLXqO%3DQ52_kddgbctwORhGDw%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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