go-silly-enum

Table of Contents

• Goal
• How it works
• Installation
• Usage
• Alternatives

Simple code to extend quasi-enum support in Go

Goal

We do not have standard Enum type in go, such a pity.

The thing closest to Enum we have in Go is something like this:

type Test1Enum uint8

const (
	TestVal11 Test1Enum = iota
	TestVal12
	TestVal13
)

This is Ok (not really), but there a some glitches.

The one most annoying for me is we will see the number printing the Enum value.

fmt.Printf("TestVal11=%v\n", TestVal11)
// Output is TestVal11=0x1, and I personally hate it.

Fortunately, we can fix with providing proper String() method for the type Test1Enum.

type Test1Enum uint8

func (v Test1Enum) String() string {
	switch v {
	case TestVal11:
		return "TestVal11"
	case TestVal12:
		return "TestVal12"
	case TestVal13:
		return "TestVal13"
	default:
		return fmt.Sprintf("Test1Enum=%v", uint8(v))
	}
}

const (
	TestVal11 Test1Enum = iota
	TestVal12
	TestVal13
)

fmt.Printf("TestVal11=%v\n", TestVal11)
// Output is TestVal11=TestVal11, nice.

Unfortunately, it could be annoying to maintain such String() methods for all the Enums we have.

Fortunately, String() methods could be generated automatically!

How it works

This app scanning the packages provided for the typed constants with type name has Enum suffix.

For each such type it generates String(), MarshalJSON() ([]byte, error), UnmarshalJSON(data []byte) error methods with all the found relative consts in use.

Installation

go install github.com/Djarvur/go-silly-enum/cmd/silly-enum-codegen@latest

Usage

silly-enum-codegen generate --verbose ./internal/extractor/testdata

Alternatives

• go-enum generates enums from comments. Great, but the values could not be used in the code without codegen, which could be annoing.