Hi bsr,
I'd suggest to use a struct type with a single string field. It will
prevent conversion from untyped string constant "by mistake".
Moreover, if you make the string field unexported, you can limit new
instance creation to the declaring package, allowing to enforce predefined
values.
Unlike with some other languages, there is no memory or runtime overhead
due to encapsulating the string within a struct.
HTH,
Peter
On Thu, Nov 7, 2019 at 7:58 PM bsr <bsr...@gmail.com> wrote:
> Hello,
>
> I am a long time user of go, but I always had the impression that below
> code would not work as string and Status are different type.
> I thought I need to explicitly convert as ```exec(Status("abc"))``` it to
> work.
>
> I think, this part of the spec may be the reason
> https://golang.org/ref/spec#Assignability
>
> - x is an untyped constant <https://golang.org/ref/spec#Constants>
> representable <https://golang.org/ref/spec#Representability> by a
> value of type T.
>
> Is there a way I can prevent this behavior.
> I am using Status like an enum, and only predefined status values should
> be allowed.
>
>
>
>
> https://play.golang.org/p/4zsb7KtPBC6
>
> package main
>
> import (
> "fmt"
> )
>
> type Status string
>
> func main() {
> exec("abc")
> }
>
> func exec(s Status) {
> fmt.Printf("Hello, %s", s)
> }
>
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