Thanks a lot! On Mar 6, 2018 5:22 PM, "Burak Serdar" <bser...@ieee.org> wrote:
> On Tue, Mar 6, 2018 at 2:58 PM, Bharath Ram <bharathram...@gmail.com> > wrote: > > In that case, for a nested struct from top to bottom, all the values are > > copies as values, correct? i.e, string, int, float, array etc will be > copied > > by value & map, slice, channel etc will be copied as pointers if they are > > initialized? > > > > https://play.golang.org/p/NzH8LVyQ0rp code works as I wanted. Generally, > > what practice should I follow? If I want a shared variable, should I > have to > > keep all the variables as pointers like in the example > > (https://play.golang.org/p/NzH8LVyQ0rp) or like the way I showed > earlier? > > It depends on the case. What exactly do you want to do? I find dealing > with the semantics of copies of structures harder to comprehend, so I > try to avoid it when the structure has reference types, but sometimes > it is really useful. For instance, if the structure will be used as > read-only and has a reasonable size, a copy of it is just fine. In my > opinion, the only general rule is that you have to know how the data > is organized and that you know what you're doing. > > > > > On Tuesday, March 6, 2018 at 3:40:47 PM UTC-5, Burak Serdar wrote: > >> > >> On Tue, Mar 6, 2018 at 1:23 PM, <bharat...@gmail.com> wrote: > >> > go version 1.10 > >> > > >> > > >> > Operating system and processor architecture > >> > > >> > GOHOSTARCH="amd64" > >> > GOHOSTOS="darwin" > >> > However, this happens in play.golang.org env as well. > >> > > >> > > >> > Checkout the code. > >> > > >> > https://play.golang.org/p/v6u7R_nbGRp > >> > >> doc1 := Document{} > >> // Here, doc1.Data is nil > >> > >> ds := DataStore{Doc: doc1} > >> // Here, ds.Doc has a copy of doc1, and ds.Doc.Data is nil > >> > >> ds.Doc.Data = DocData{} > >> // Here, ds.Doc.Data is initialized, but not doc1.Data, because > >> ds.Doc is a copy of doc1 > >> > >> > >> On the other hand: > >> > >> doc2 := Document{Data: DocData{}} > >> // Here, doc2.Data is initialized to an empty map > >> ds2 := DataStore{Doc: doc2} > >> // And here, ds2.Doc is a copy of doc2, which contains a reference to > >> that empty map. The underlying maps are shared. > >> > >> > >> > >> > > >> > > >> > In the example, if the struct (Document) is not initialized at first, > >> > there > >> > is no place holder for future values pointing to same object. Is this > >> > intended? > >> > > >> > -- > >> > 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...@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. > -- 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.
