I'm in favor of the square brackets. scala has them as well so we're not exactly blazing a new trail. I'm not in favor of a second `type` keyword whose benefit is to disambiguate syntax to the parser. we already use significant whitespace to identify tokens. for example, we expect to be parsing a function after we've parsed the `func\s+`. I'll take a parsing error over repeated the type keyword. In this regard we're not along either. Erlang's less-than-or-equals operator is =<. It inadvertently makes whitespace a requirement when doing binary syntax: `X = <<"hello">>`. Without the significant whitespace after the equals sign, the Erlang parser always finds the `=<` operator, which leads to a parsing error. A similar behavior for the square brackets syntax will be desirable.
On Wed 15 Jul 2020 at 09:32 Max <massimiliano.ghila...@gmail.com> wrote: > 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 > <https://groups.google.com/d/msgid/golang-nuts/1e8397a5-bcc9-48b8-924b-1d35f4434d14o%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- *Curried programmer* *Homepage*: http://yawboakye.com I'm tweeting <https://twitter.com/@22bytes> when I'm not coding <https://github.com/yawboakye> when I'm not holding my niece. -- 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/CAPJoGXtWxdEf8iyhWjuOeWv_fEtWLtfbkU7ZTnvDOtvYjPVy5w%40mail.gmail.com.
