On 3/13/21 1:40 PM, Axel Wagner wrote: > > Compiler complication is not the concern. It would be easy to build any of the > suggested semantics into the language. It is just that none of the suggestions > so far seem clearly better - that is, they all come with their own downsides. >
OK, I really meant, GC complexity, etc. Perhaps it does not affect that either. > The concern about the zero value consisting of 0 bytes is more about > performance. As long as that's the case, initialization is very close to free. > As soon as the zero value becomes some non-zero bytes, they have to be written > and that incurs a cost. > > When we say "the zero value of a map should only contain zero bytes", what we > mean is that if I write > var m map[int]int > that should a) reserve some memory for m (currently that's as many bytes as a > pointer needs) and b) those bytes should be zero after that. > If "make was called implicitly" or anything like that, those bytes wouldn't be > zero anymore - they would contain a pointer to an allocated map header. > > It's as simple as that. You might feel that preserving that property is not > important or less important than having a useful zero value for maps. That's > fine. But that's the property Ian is talking about. In that case, as far as I understand it, which may be a limited understanding. I disagree with this being a useful property. Replacing a map of 0 length with one that is larger is not a problem. Checking the length of a map also makes more sense to me than nil. Though I personally do not agree with Nulls in JSON either. An intentional empty is always more useful. Similarly, nulls when permitted always being unintentional is more useful in my eyes. -- 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/b962ffa5-0201-bffb-90c0-8f6de262d9a7%40gmail.com.
