Option Type for Go

The Option package provides an Option type that represents encapsulation of an optional value; a value that may either contain a value (Some) or not contain a value (None), similar to Option in Rust.

Features

• Some: Create an Option that contains a value.
• None: Create an Option that represents no value.
• Ok: Return the value if it exists.
• Cause: Return the cause of None if it is due to an error.
• Process: Transform the Option value with a function that might fail.
• Map: Transform the Option value with a function that cannot fail.
• Flatten: Nested Option values into a single Option.
• Wrap: Wraps a value and an error into an Option.
• WrapFn: Wraps a function that returns a value and an error into a function that returns an Option.

Installation

To use the Option package in your Go project, place the package in your project directory or a suitable location in your GOPATH. Import it using:

go get -u github.com/AY7295/go-option

Usage Examples

Here are some basic examples of how to use the Option type:

Creating Some and None

opt1 := option.Some(10)
opt2 := option.None[int]()

Processing an Option

opt := option.Some(5)
result := option.Process(opt, func(v int) (int, error) {
    if v == 0 {
        return 0, errors.New("zero value")
    }
    return 2 * v, nil
})

Mapping over an Option

opt := option.Some(10)
mapped := option.Map(opt, func(v int) int {
    return v + 1
})

Flattening an Option

doubleWrapped := option.Some(option.Some(20))
flattened := option.Flatten(doubleWrapped)

Testing

To run the tests for the Option package, navigate to the package directory and execute:

go test

This will run all the tests defined in option_test.go.