Re: [go-nuts] Re: What is the problem of the generic use?

[Axel Wagner]

Please ask an actual question, don't just post some code.

FTR the code you posted (with the substitution you suggest) compiles and runs fine using gotip.

On Fri, Nov 12, 2021 at 6:18 AM tapi...@gmail.com <tapi...@gmail.com> wrote:

sorry, a mistake, "int" -> "[]byte".

On Friday, November 12, 2021 at 1:08:50 PM UTC+8 tapi...@gmail.com wrote:

package main

import (
    "fmt"
)

type byteview interface{string | int}

type ByteView[T byteview] struct {v [0]T}

func (bv ByteView[T]) Write(v T) (int, error) {
    return 0, nil
}

type Writer[T byteview] interface {
    Write(bs T)(int, error)
}

type ioWriter = Writer[[]byte] // []byte does not satisfy comparable

func main() {
    fmt.Println("Hello, playground")
}

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[Axel Wagner]

Why not? The comment "[]byte does not satisfy comparable" seems irrelevant, as you don't use that constraint anywhere. It seems pretty well-defined, if strange and pointless, code.

On Fri, Nov 12, 2021 at 6:20 PM tapi...@gmail.com <tapi...@gmail.com> wrote:

fine? It should not.

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[Axel Wagner]

To be clear: You sent a follow-up E-Mail to your original code, to replace `int` with `[]byte`. That substitution is, of course, necessary to make the code compile. So, specifically, this compiles fine:

package main

import (
    "fmt"
)

type byteview interface{string | []byte}

type ByteView[T byteview] struct {v [0]T}

func (bv ByteView[T]) Write(v T) (int, error) {
    return 0, nil
}

type Writer[T byteview] interface {
    Write(bs T)(int, error)
}

type ioWriter = Writer[[]byte]

func main() {
    fmt.Println("Hello, playground")
}