go-enum

go-enum - Typesafe enum generation in golang

This package provides a scaffolding mechanism to generate enum types based on string values, in contrast with the iota based integer constants enum pattern commonly used in Go

Use this package if you wish to have type support for:

• Traversable enumerations
• Enum fields compatible with several (un)marshal interfaces:
  • Stringer
  • json.Marshaler, json.Unmarshaler
  • text.Marshaler, text.Unmarshaler
  • json.Marshaler, json.Unmarshaler
  • gob.GobEncoder, gob.GobDecoder
  • driver.Valuer, sql.Scanner
  • bson.Marshaler, bson.Unmarshaler (from go.mongodb.org/mongo-driver/bson package)
• Ability to perform type-safe comparisons at runtime against strings and instances of the same enum type

For more information on the enumeration type API, see the example:

Usage

This generator uses the go generate command, and as such, its pattern must be used in order to generate code

As shown in the example package, 2 files are needed:

example.go

package example

//go:generate go run gen_enums.go

gen_enums.go

// +build ignore

package main

import (
	"fmt"
	"os"

	"github.com/lggomez/go-enum/generator"
)

// This example generates the 'Ghost', 'Thing' and 'CountriesIso31661' enums inside of an 'enum' subpackage
// To generate them on the current package instead, just use the current directory path (".")
func main() {
	generator.GenerateEnumTypes(
		generator.Options{
			PackageDirectoryPath: fmt.Sprintf(".%venum", string(os.PathSeparator)),
			PackageImportPath:     "github.com/lggomez/go-enum/example/enum",
			ValueIdentifierCasing: generator.CamelCase,
			OmitGeneratedNotice:   false,
			OmitTests:             false,
			OmitNameSanitization:  false,
			OmitSourceFormatting:  false,
		},
		generator.StringEnumDefinition{
			Name:   "Ghost",
			Values: []string{"Blinky", "Pinky", "Inky", "Clyde"},
		},
		generator.StringEnumDefinition{
			Name:   "SpecialThing",
			Values: []string{"Foo", "Bar", "Baz", "Quux"},
		},
	)
	generator.GenerateEnumTypes(
		generator.Options{
			PackageDirectoryPath: fmt.Sprintf(".%venum", string(os.PathSeparator)),
			PackageImportPath:     "github.com/lggomez/go-enum/example/enum",
			ValueIdentifierCasing: generator.UpperCase,
			OmitGeneratedNotice:   false,
			OmitTests:             false,
			OmitNameSanitization:  false,
			OmitSourceFormatting:  false,
		},
		generator.StringEnumDefinition{
			Name:   "CountriesISO3166-1",
			Values: []string{"Ca", "Uy", "Us", "Ar"},
		},
	)
}

With both files present in the same directory/package, execute the go generate command on that directory

Based on this example, it will generate an enum subpackage with the Ghost and Thing enum types, along with its iterators EnumGhost and EnumThing