gopts

README

Gopts

Gopts is a small package to handle options in Go heavily inspired by Rust's Option enum.

basically, it's a wrapper around

if x != nil {
    return *x
}

Import

go get github.com/karim-w/gopts

Usage

package main

import (
    "log"
    "github.com/karim-w/gopts"
)

func getOption() gopts.Option[int] {
    // Create an option with a value
    return gopts.Some(5)
}

func getNothing() gopts.Option[int] {
    // Create an option with no value
    return gopts.None[int]()
}

func main() {
    // an option
    val := getOption()

    // check if there is a value
    if val.IsSome() {
        // pull the value
        num := val.Unwrap()

        log.Println("Value is", num)
    }

    // an option with no value
    val = getNothing()

    // check if there is nothing
    if val.IsNone() {
        log.Println("No value")
    }


    defer func() {
        if r := recover(); r != nil {
            log.Println("Panic:", r)
        }
    }()


    // when pulling a value from an option with no value
    // it will panic
    val.Unwrap()

}

License

BSD 3-Clause License

Author

karim-w

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Documentation

Index

• type Option
  • func None[T any]() Option[T]
  • func Some[T any](value T) Option[T]
  • func (o Option[T]) Get() (res T, ok bool)
  • func (o Option[T]) GetOrElse(defaultValue T) (res T)
  • func (o Option[T]) IsNone() bool
  • func (o Option[T]) IsSome() bool
  • func (o Option[T]) MarshalJSON() ([]byte, error)
  • func (o *Option[T]) Scan(value interface{}) error
  • func (o *Option[T]) UnmarshalJSON(data []byte) error
  • func (o Option[T]) Unwrap() (res T)
  • func (o Option[T]) Value() (driver.Value, error)

Types

type Option

type Option[T any] struct {
	// contains filtered or unexported fields
}

Option is a generic type that can be used to represent a value that may or may not be present.

func None

func None[T any]() Option[T]

None returns an Option[T] with no value. Example:

opt := None()
fmt.Println(opt.IsNone()) // true

func Some

func Some[T any](value T) Option[T]

Some returns an Option[T] with a value. Example:

opt := Some(42)
fmt.Println(opt.IsSome()) // true

func (Option[T]) Get

func (o Option[T]) Get() (res T, ok bool)

Get returns the value of the Options[T] and a boolean indicating if the value is present. Example:

opt := Some(42)
val, ok := opt.Get()
fmt.Println(val, ok) // 42, true

func (Option[T]) GetOrElse

func (o Option[T]) GetOrElse(defaultValue T) (res T)

GetOrElse returns the value of the Options[T]. If the Options[T] has no value, it returns the default value. Example:

opt := Some(42)
fmt.Println(opt.GetOrElse(0)) // 42

func (Option[T]) IsNone

func (o Option[T]) IsNone() bool

IsNone returns true if the Options[T] has no value. Example:

opt := None()
fmt.Println(opt.IsNone()) // true

func (Option[T]) IsSome

func (o Option[T]) IsSome() bool

IsSome returns true if the Options[T] has a value. Example:

opt := Some(42)
fmt.Println(opt.IsSome()) // true

func (Option[T]) MarshalJSON

func (o Option[T]) MarshalJSON() ([]byte, error)

MarshalJSON implements the json.Marshaler interface.

func (*Option[T]) Scan

func (o *Option[T]) Scan(value interface{}) error

Scan implements the sql.Scanner interface for Option

func (*Option[T]) UnmarshalJSON

func (o *Option[T]) UnmarshalJSON(data []byte) error

UnmarshalJSON implements the json.Unmarshaler interface.

func (Option[T]) Unwrap

func (o Option[T]) Unwrap() (res T)

Unwrap returns the value of the Options[T]. If the Options[T] has no value, it panics. Example:

opt := Some(42)
fmt.Println(opt.Unwrap()) // 42

func (Option[T]) Value

func (o Option[T]) Value() (driver.Value, error)

Value implements the driver.Valuer interface for Option[T]