Can you make it work on play.golang.org, from this code https://play.golang.org/p/QjCtD9rGpa, according to your plan?
On Wed, Nov 23, 2016 at 10:14 AM, Nick Patavalis <nick.patava...@gmail.com> wrote: > Yes... so every specific animal type implements it's own Output() method, > which does the trivial IsA() part, and calls Animal's Output() for the > common complicated parts... > > On Nov 23, 2016 16:35, "Tong Sun" <suntong...@gmail.com> wrote: > >> Have you noticed the IsA() func call there? >> >> On Wed, Nov 23, 2016 at 4:05 AM, Nick Patavalis <nick.patava...@gmail.com >> > wrote: >> >>> Hi, >>> >>> In your *second* example, making Output() a method of Animal will work, >>> since it uses only the members (fields) of Animal, and not the fields of >>> specific animals (or any behavior that varies between animals). That's why >>> I'm insisting on *real* and *specific* examples, not synthetic ones. >>> >>> /npat >>> >>> On Wednesday, November 23, 2016 at 6:08:00 AM UTC+2, Tong Sun wrote: >>>> >>>> No Nick, making Output() a member method won't work. >>>> See my OP and Jesse's answer. I.e., I have to change it from a member >>>> function to a pure function. >>>> >>>> On Tue, Nov 22, 2016 at 6:25 PM, Nick Patavalis <nick.pa...@gmail.com> >>>> wrote: >>>> >>>>> Hi, >>>>> >>>>> There is no direct mapping of what you can do with virtual functions >>>>> in other OO languages, and Go. There are different compromises you have to >>>>> make; because of this, synthetic examples will probably not help much. >>>>> >>>>> That being said, in the case of your last example I would make >>>>> Output() a method of Animal. >>>>> The Speak() methods of the specific animals would then call Output(). >>>>> >>>>> /npat >>>>> >>>>> On Wednesday, November 23, 2016 at 12:03:54 AM UTC+2, Tong Sun wrote: >>>>>> >>>>>> >>>>>> >>>>>> On Tue, Nov 22, 2016 at 4:29 PM, Jesse McNelis wrote: >>>>>> >>>>>>> On Wed, Nov 23, 2016 at 8:16 AM, Tong Sun wrote: >>>>>>> > Hi, >>>>>>> > >>>>>>> > How to architect the OO's virtual function in Go? >>>>>>> > >>>>>>> > Please take a look at this (not working) Go program >>>>>>> > https://play.golang.org/p/qrBX6ScABp >>>>>>> > >>>>>>> > Please think of the "func Output()" as a very complicated function >>>>>>> that I >>>>>>> > only want to define once at the base level, not to duplicate into >>>>>>> each sub >>>>>>> > classes. >>>>>>> > >>>>>>> > How can I make it works so that the last output statement, instead >>>>>>> of being, >>>>>>> > >>>>>>> > fmt.Printf("[%v] %s: [%0.2f]\n", k, v.Name(), v.Area()) >>>>>>> > >>>>>>> > >>>>>>> > will be this instead: >>>>>>> > >>>>>>> > fmt.Printf("[%v] %s\n", k, v.Output()) >>>>>>> > >>>>>>> >>>>>>> You define a function: >>>>>>> >>>>>>> func Output(s Shape) string { >>>>>>> return s.Name() + "'s area size is " + s.Area() >>>>>>> } >>>>>>> >>>>>>> Go uses interfaces for polymorphism. >>>>>>> Other OOP languages can use inheritance for polymorphism too, but Go >>>>>>> doesn't have inheritance. >>>>>>> >>>>>> >>>>>> Thanks Jesse. That works. >>>>>> >>>>>> However I just realized that it is only part of my problem. >>>>>> >>>>>> I have a huge list of common variables that I defined in my "base >>>>>> class", changing it from a member function to a pure function causes >>>>>> almost >>>>>> every single variable now undefined. >>>>>> >>>>>> I can demonstrate the problem with this code >>>>>> https://play.golang.org/p/QjCtD9rGpa >>>>>> >>>>>> So, once again, thinking in OO, I'll define all of the common >>>>>> variables in base class, and common functionalities in virtual functions. >>>>>> How to make that idea work in Go? >>>>>> >>>>>> For the above specific code, how to easily make "func Output" works? >>>>>> >>>>>> Thanks >>>>>> >>>>>> -- >>>>> 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/to >>>>> pic/golang-nuts/f_62HEOIBV4/unsubscribe. >>>>> To unsubscribe from this group and all its topics, send an email to >>>>> golang-nuts...@googlegroups.com. >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> -- >>> 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/to >>> pic/golang-nuts/f_62HEOIBV4/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> golang-nuts+unsubscr...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- 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. For more options, visit https://groups.google.com/d/optout.
