GO中的结构枚举

Question

I would like to enumerate the planets in my Go program. Each planet includes a common name (ex: "Venus") and a distance from the sun in Astronomical Unit (ex: 0.722)

So I wrote this code :

type planet struct {
    commonName string
    distanceFromTheSunInAU float64
}

const(
    venus planet = planet{"Venus", 0.387}      // This is line 11
    mercury planet = planet{"Mercury", 0.722}
    earth planet = planet{"Eath", 1.0}
    mars planet = planet{"Mars", 1.52}
    ...
)

But Go didn't let me compile this, and gave me this error :

# command-line-arguments
./Planets.go:11: const initializer planet literal is not a constant
./Planets.go:12: const initializer planet literal is not a constant
./Planets.go:13: const initializer planet literal is not a constant
./Planets.go:14: const initializer planet literal is not a constant

Do you have any idea of how I could do? Thanks

Answer 1

Go does not support enums. You should either define your enumerated fields as vars or to ensure immutability, maybe use functions that return a constant result.
For example:

type myStruct { ID int }

func EnumValue1() myStruct { 
    return myStruct { 1 } 
}

func EnumValue2() myStruct { 
    return myStruct { 2 } 
}