Go Enumerations

External

• https://blog.boot.dev/golang/golang-enum

Internal

• Constants
• Go Language
• iota

Overview

Go does not have formal enums, but the language allows for sets of related, yet distinct int constants. They represent a property that has several distinct possible int values, like the days of the weeks or the months of the year. They are declared using the pre-declared constant iota:

type DayOfTheWeek int
const (
  MON DayOfTheWeek = iota
  TUE
  WED
  THU
  FRI
  SAT
  SUN
)

To make the enumeration constants visible outside the package, they need to start with a capital letter.

Conversion to and from string representations:

type DayOfTheWeek int

const (
	MON DayOfTheWeek = iota
	TUE
	WED
	THU
	FRI
	SAT
	SUN
)

var dayOfTheWeekToString = []string{
	"Monday",
	"Tuesday",
	"Wednesday",
	"Thursday",
	"Friday",
	"Saturday",
	"Sunday",
}

func (s DayOfTheWeek) String() string {
	return dayOfTheWeekToString[s]
}

func StringToDayOfTheWeek(s string) DayOfTheWeek {
	for i, v := range dayOfTheWeekToString {
		if s == v {
			return DayOfTheWeek(i)
		}
	}
	return DayOfTheWeek(-1)
}