I think square brackets are better than parentheses for several reasons: 1. fewer parser ambiguities (see the post that started this thread) - thus fewer cases where programmers must remember "oh, this is a special case, I must put additional parentheses somewhere" 2. programmers can distinguish more easily between a template instantiation `T1[T2]` and a function call `T1(T2)`. Index expressions would have the same syntax as single-type template instantiations `T1[T2]`, but I believe they are somewhat less common than function calls in most code 3. Go already uses a similar syntax for builtin types: `map[K]V`. A generic key/value container would look like `Map[K, V]` which is pretty close
In my Go interpreter, I went a step further and implemented the syntax `T1#[T2, T3]` for generics instantiation. It may not be everybody's favorite, but removes all parsing ambiguities. An alternative syntax, more similar to other proposals I have seen, is `T1:[T2, T3]` - it could be visually better, but I think it introduces ambiguities in `case` and labels marking `goto` destinations - both already use ':' as delimiter. On Wednesday, July 15, 2020 at 6:14:31 AM UTC+2, Ian Lance Taylor wrote: > > > The advantage of parentheses is that the language already uses > parentheses for lists in various places. Of course that is also the > disadvantage. > > When considering something other than parentheses, I encourage people > to look for objective reasons why one syntax is better than another. > It's going to be different from other aspects of the language. So > what reason would we have for preferring one syntax over another? > > For example: > > Robert already gave reasons why square brackets are better than angle > brackets. > > The disadvantage of guillemets is that they are hard to type on many > keyboards. So to me either square brackets or angle brackets would be > better than guillemets. > > The disadvantage of a two character sequence such as <: :> is that it > is more typing. So again either square brackets or angle brackets > seem to me to be better. > > An example of a reason that square brackets might be a poor choice > would be ambiguous parsing, or cases where the code is harder to read. > > It's true that some other languages use angle brackets, but Go already > does many things differently. That is only a minor advantage for > angle brackets. To me at least it does not outweigh the > disadvantages. > > In short, please try to provide reasons for a different syntax. "It > looks good" is a valid reason, but please try to explain why it looks > better than square brackets or parentheses. > > Thanks. > > Ian > -- 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/1e8397a5-bcc9-48b8-924b-1d35f4434d14o%40googlegroups.com.
