I got hit by a car last night. As I was sitting in the emergency room I
realized the answer to Russ Cox's 2011
riddle https://groups.google.com/g/golang-nuts/c/0bcyZaL3T8E - you
disambiguate as you're placing the item in the sum-type/box.
type RW union {
io.Reader
io.Writer
}
mean? Or is it d
First of all, thank you for your effort into this! Impressive stuff. I am
not a compiler expert, but the repo made it easier to understand the ideas
you are talking about for someone like me. That being said, my following
questions are a step towards understanding what is and isn't possible in
Thanks for engaging. It was a lot of work. Per observations from 2011,
interfaces in discriminated unions creates a mess. This implementation
avoids that mess by disallowing them. Interfaces are extremely good at
providing polymorphism for behaviors. Sum types/Discriminated unions serve
a diffe
FWIW you can model a sum as a product plus a tag. That is, you can implement
Maybe[T] = None | Some T
match m {
case None:
// do thing
case Some v:
// do thing with v
}
as
type Maybe[T any] struct {
Case int // 0 or 1
None struct{}
Some T
}
switch m.Case {
case 0:
// do th
On Tue, 2 Sept 2025 at 12:56, Cliff wrote:
> From an implementation, language theory, and sanity point of view: putting
> non-concrete types in a sum type won't work. If the design principles of go
> demand interfaces in sum types, they will never be workable.
Why not? In a union they don't wor
Hi,
On Tue, 2 Sept 2025 at 00:48, Jason E. Aten wrote:
> I'm neutral.
>
> + I like the exhaustiveness checking this enables.
> […]
> _ what happens when interfaces are choices inside a box? Go values
> orthogonality and composability, so this would be a natural thing
> for a developer to do.
>
I should proof-read *before* hitting send:
On Tue, 2 Sept 2025 at 11:00, Axel Wagner
wrote:
> It seems most likely (based on statements by the Go team) that we would
> not want to add a new concept that has this much semantic overlap with
> `interface{ a | b | c }`. But if we did that, the resul
On Monday, 1 September 2025 at 23:47:50 UTC+1 Jason E. Aten wrote:
- I don't like there being a new way to return an error, in effect hiding
the
fact that an error was returned inside a box. Having multiple return
values with one of them being an error has become idiomatic, and
I find this helps
I'm neutral.
+ I like the exhaustiveness checking this enables.
+ I like the potential for efficiency if only one of the union types needs
to
be allocated and there are a large number of possibilities.
- I don't like the re-use of the type switch because it hurts the
readability in
that curre
