Enums

Go has no built-in enum type - idiomatic enums use typed integer constants with iota to generate sequential values.

Go has no dedicated enum type. A common pattern is a named integer type with constants; iota is the index of each constant specification in its declaration, starting at zero.

This typed constant group represents directions. The switch also returns a fallback for values outside the declared constants.

package main
 
import "fmt"
 
type Direction uint8
 
const (
    Unknown Direction = iota
    North
    East
    South
    West
)
 
func label(d Direction) string {
    switch d {
    case North:
        return "north"
    case East:
        return "east"
    case South:
        return "south"
    case West:
        return "west"
    case Unknown:
        return "unknown"
    default:
        return "invalid"
    }
}
 
func main() {
    fmt.Println(label(East))
}

In production

The compiler does not check whether a switch handles every enum constant. Values converted from integers or decoded from input can also be outside the declared set, so keep a default case and validate external values.

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