And make the standard library unmagical? One of the things I've always disliked about Go is how stdlib provides magic facilities unavailable to user code.
* the "time" package hooks into the Go scheduler.
* the "reflect" package needs type information out of the runtime.
* the "net" package hooks into the Go scheduler a bit. But way less than it used to. I think you might even be able to do this all yourself outside of std nowadays.
What else?
Our rough plan going forward is to actually move a bunch of the stdlib elsewhere but ship copies/caches of tagged versions with Go releases. So maybe "encoding/json" is really an alias for "golang.org/std/encoding/json" and Go 1.13.0 ships with version 1.13.0 of golang.org/std/encoding/json. But if you need a fix, feature, or optimization sooner than 6 months when 1.14.0 comes out, you can update earlier.
1. The constructs like "x <- chan" and "x, ok <- chan" (and map indexing and so on) are only available to builtin types.
It's impossible to write a thing like "x, ok <- chan" where it either panics or doesn't depending on if the caller wanted two or one return values.
2. generic types, like 'map' and 'chan'.
3. 'len' can't be implemented for a user type, e.g. "len(myCustomWorkQueue)" doesn't work.
4. range working without going through weird hoops (like returning a channel and keeping a goroutine around to feed it)
5. Reserving large blocks of memory up front (e.g. as 'make' can do for slices and maps) in an efficient manner (e.g. make(myCustomWorkQueue, 0, 20) doesn't work)
It really doesn't. Maps and channels are not part of the stdlib. They're part of the language, but not the library.
Similarly, range is part of the language, not the stdlib.
If the stdlib was privileged, "container/*" in it would be generic, but it's not.
Consider that make, map, chan etc are just language features/specs just like int64, string, func, main etc
But higher level data structures like lists, sets, maps etc. are all implemented using those primitives under the hood. So, especially in a "systems language", I would sort of expect them to just be libraries in the stdlib, not language features[1]. But if you think otherwise (or see a gap in my reasoning) I'd love to hear why!
[1] Except maybe some syntactic sugar for list/dict/set literals.
> But higher level data structures like lists, sets, maps etc. are all implemented using those primitives under the hood. So, especially in a "systems language", I would sort of expect them to just be libraries in the stdlib, not language features[1].
Maybe! But if those higher order structures are closer to language features than libraries -- and, specifically to this conversation, if they leverage parts of the runtime that aren't available to mere mortals -- is it a strictly worse outcome? I don't know. Some evidence might suggest yes. But I think it's at best arguable.
In Go you don't have generics as a primitive with which to build those things.
As a result, you don't have the building blocks for anyone to build a usable data structure unless it's baked into the core of the language.
> Should [be just libraries]? I think you are asserting facts that are not in evidence.
I tried to describe why I feel that go's collections should be libraries and not builtins, and hopefully understand why GP seemed like they were questioning that idea.