option

Option type for golang

Install

go get -u github.com/cospectrum/option

Requires Go version 1.22.0 or greater.

Usage

import (
	"fmt"

	"github.com/cospectrum/option"
)

func main()
	divide := func(numerator, denominator float64) option.Option[float64] {
		if denominator == 0.0 {
			return option.None[float64]()
		}
		return option.Some(numerator / denominator)
	}

	// The return value of the function is an option
	result := divide(2.0, 3.0)

	// Pattern match to retrieve the value
	result.Match(
		func(val float64) {
			fmt.Printf("Result: %v\n", val)
		},
		func() {
			fmt.Println("Cannot divide by 0")
		},
	)
}

JSON

type U struct {
	Num option.Option[int] `json:"num"`
}

var u U
json.Unmarshal([]byte(`{"num": null}`), &u) // => U{Num: option.None()}
json.Unmarshal([]byte(`{}`), &u) // => U{Num: option.None()}
json.Unmarshal([]byte(`{"num": 0}`), &u) // => U{Num: option.Some(0)}
json.Unmarshal([]byte(`{"num": 3}`), &u) // => U{Num: option.Some(3)}