go-silly-enum

README

= go-silly-enum image:https://godoc.org/github.com/Djarvur/go-silly-enum?status.svg["GoDoc",link="http://godoc.org/github.com/Djarvur/go-silly-enum"] image:https://github.com/Djarvur/go-silly-enum/workflows/Test/badge.svg?branch=master["Build Status"] image:https://coveralls.io/repos/Djarvur/go-silly-enum/badge.svg?branch=master&service=github["Coverage Status",link="https://coveralls.io/github/Djarvur/go-silly-enum?branch=master"]
Daniel Podolsky
:toc:


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:

[source,go]
----
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.

[source,go]
----
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.

[source,go]
----
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

[source,sh]
----
go install github.com/Djarvur/go-silly-enum/cmd/silly-enum-codegen@latest
----

== Usage

[source,sh]
----
silly-enum-codegen generate --verbose ./internal/extractor/testdata
----

== Alternatives

- https://github.com/abice/go-enum[go-enum] generates enums from comments. Great, but the values could not be used in the code without codegen, which could be annoing.