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The parens for the type parameters is the one thing Go got right in the entire language.

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· Jul 31, 2019

Replying to @omengue @golang and @ianlancetaylor

My main concern is the syntax. Parentheses for type parameters are hard to distinguish from parentheses value parameters. The FAQ mentions that F<T> and F[T] have been considered and rejected. The pain will be on the users to "to keep the parser simple".

Manish

@ManishEarth

Aug 1, 2019

it does mean that you can now have a total of four sets of parens in a function def: func (type T) (s Foo*) Bar(arg1 Baz, arg2 Baz2) (bool, Quux)

Manish

@ManishEarth

Aug 1, 2019

not ... terrible, and I still think it's an overall good choice, but still kinda weird

Joshua Yanovski

@awesomeintheory

Aug 1, 2019

It makes it clearer that generics are functions applied to types, I like it a lot. Gives Go a leg up on the path to dependent types!

Anthony Ramine

@nokusu

Aug 1, 2019

Step 1: get tagged unions.

Joshua Yanovski

@awesomeintheory

Aug 1, 2019

It should already have them, tagged unions are compatible with the "Go philosophy" in every way I can think of... every language should have them though.

Anthony Ramine

@nokusu

Aug 1, 2019

AFAIK the Powers That Be say that tagged unions don't bring much to interface types so they don't want them.

Joshua Yanovski

@awesomeintheory

Aug 1, 2019

My first instinct is to say "but those aren't the same thing!" but if it's a feature-for-feature trade I'd happily give up interfaces for tagged unions. Can always use records with functions in them instead, they're not even that bad to use.

Replying to

and

I thought the issue was more that they started out with the assumption that everything needed a default value. Anyway, that means it's hard to have a default for tagged unions (which should have given them a hint that defaults for everything is kinda ick, but egh).

1:57 PM · Aug 1, 2019Twitter Web App

Replying to

and

It's not hard to have a default for tagged unions anyway, just make people specify one as the default (though why you insist on this I have no earthly idea).