Schrodingo

Golang Result Monad library to easily manage errors.

Why this name?

Using Schrodingo, a function can return a value which can be either a Sucess or a Failure. This makes me think about the Schrodinger's cat experience (where the cat was dead and alive at the same time).

⚠️ Warning ⚠️

This project requires Go generics which are still in development.

So this project is for experimental usage only.

Result Monad

This library aims to ease the management of errors in Go using the Either Monad which can be either a Success (which contains a value), or a Failure (which contains an error).

Is it largely inspired by the Result class in Kotlin.

Installation

Don't install it until Go generics are a thing.

Usage

Classic error handling

func DoOtherThing() (int, error){
	return 32, nil
}

func DoSomethingElse(input int) (float32, error){
    return 32.0, nil
}

func DoOneLastThing(input float32) (string, error){
	return "", fmt.Errorf("boom")
}

func DoSomething() error {
	i, err := DoOtherThing()
	
	if err != nil {
		return err
	}
	
	f, err := DoSomethingElse(i)
	
	if err != nil {
		return err
	}
	
	s, err := DoOneLastThing(f)
	
	if err != nil {
		return err
	}
	
	fmt.Println(s)
}

func main() {
	err := DoSomething()
	
	if err != nil {
		panic(err)
	}
}

Using Schrodingo

func DoOtherThing() Result[int]{
	return Success(32)
}

func DoSomethingElse(input int) Result[float32]{
    return Success(32.0)
}

func DoOneLastThing(input float32) Result[string]{
	return Failure(fmt.Errorf("boom"))
}

func DoSomething() error {
	i := DoOtherThing()
	f := ThenDo(i, func(i int) Result[float32] {
		//This function will be called only if DoOtherThing() didn't returned an error
		return DoSomethingElse(i)
	})
	s := ThenDo(f, func(f float32) Result[string] {
		//This function will be called only if DoSomethingElse() didn't returned an error
		return DoOneLastThing(f)
	})
	
	s.OnSuccess(func(s string) {
		//This function will be called only if DoOneLastThing() didn't returned an error
		fmt.Println(s)
	})
	
	return s.ErrorOrNil() //Will return an error if any
}

func main() {
	err := DoSomething()
	
	if err != nil {
		panic(err)
	}
}

More infos here: https://melvinbiamont.medium.com/how-generics-can-change-error-handling-in-go-34f47347925a