On Wednesday, August 3, 2016 at 6:16:37 PM UTC+2, Ian Lance Taylor wrote: > > On Wed, Aug 3, 2016 at 9:12 AM, T L <tapi...@gmail.com <javascript:>> > wrote: > > > > On Wednesday, August 3, 2016 at 11:46:43 PM UTC+8, Axel Wagner wrote: > >> > >> True, but it would still be just the same loop, it wouldn't actually be > >> significantly faster. And you'd need to put quite some machinery into a > >> pretty rarely used functionality, which means it also wouldn't be > cleaner. > >> > >> The thing is, that the memory representation of []T and []J, with J > being > >> an interface type, is very different form each other and differs also > for > >> each (T, J) pair, AIUI. So you can't really efficiently generalize > this. The > >> only thing it could possibly safe you, is writing the actual loop and > in > >> general go doesn't really do this kind of tradeoff (saving small > amounts of > >> trivial work by complicating the language and -implementation). > > > > > > so the copy buitlin function is not essential? > > Correct. > > Although it is worth noting that, in the absence of significant > compiler optimizations that the gc compiler does not currently > implement, the copy builtin can be much more efficient than the > ordinary user written loop; see > https://golang.org/src/runtime/memmove_amd64.s. That is not true of a > function that converts from []T to []interface. > > Ian >
Enabling user to do conversion from []*T to []*U (the slices contain pointers) would be easy, doing a slight modification in the compilers. We did tricks like this already in modified versions of go Enabling user to do conversion from []T (T is arbitrary not just fixed size type) to []interface would be possible with a deep modification involving linkers and other stuff (that I don't understand very well). Dealing with []T when T is an interface would be nightmare difficult and I don't even know where would I begin i believe in go experts they are more than capable to deal with this -- 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.
