optional

package module

v0.0.0-...-ffc6068 Latest Latest Go to latest Published: Jun 27, 2024 License: MIT Imports: 1 Imported by: 2

Details

Valid go.mod file
Redistributable license
Tagged version
Stable version
Learn more about best practices

Repository

github.com/lanseg/golang-commons

Links

Open Source Insights

README ¶

optional

Optionals implementation for Golang

Could help to reduce amount of annoying

result, err := doSomething()
if err != nil {
  return nil, err
}
nextResult, nextErr := doSomethingElse(result)
if nextErr != nil {
  return nil, nextErr
}
finalResult, finalErr := doSomethingOneMoreTime(nextResult)
if finalErr != nil {
  return nil, finalErr
}
return finalResult

to

return optional.MapErr(
  optional.MapErr(
    optional.OfError(doSomething()),
    doSomethingElse,
  ),
  doSomethingOneMoreTime).Get()

Documentation ¶

Overview ¶

Package optional provides

Constants ¶

This section is empty.

Variables ¶

View Source

var ErrNoSuchElement = errors.New("Nothing does not contain value")

Functions ¶

func False ¶

func False[T any](value T) bool

func True ¶

func True[T any](value T) bool

Types ¶

type Error ¶

type Error[T any] struct {
	Nothing[T]
	// contains filtered or unexported fields
}

Optional subtype that contains an error

func (Error[T]) Get ¶

func (e Error[T]) Get() (T, error)

func (Error[T]) GetError ¶

func (e Error[T]) GetError() error

func (Error[T]) If ¶

func (e Error[T]) If(present func(T), err func(error), nothing func())

func (Error[T]) IfError ¶

func (e Error[T]) IfError(f func(error)) Optional[T]

func (Error[T]) IfNothing ¶

func (e Error[T]) IfNothing(func()) Optional[T]

func (Error[T]) IfPresent ¶

func (e Error[T]) IfPresent(func(T)) Optional[T]

type Function ¶

type Function[T any, U any] func(arg T) U

type Just ¶

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

Optional subtype that contains a value

func (Just[T]) Filter ¶

func (j Just[T]) Filter(p Predicate[T]) Optional[T]

func (Just[T]) Get ¶

func (j Just[T]) Get() (T, error)

func (Just[T]) GetError ¶

func (j Just[T]) GetError() error

func (Just[T]) If ¶

func (j Just[T]) If(present func(T), err func(error), nothing func())

func (Just[T]) IfError ¶

func (j Just[T]) IfError(func(error)) Optional[T]

func (Just[T]) IfNothing ¶

func (j Just[T]) IfNothing(func()) Optional[T]

func (Just[T]) IfPresent ¶

func (j Just[T]) IfPresent(f func(T)) Optional[T]

func (Just[T]) IsPresent ¶

func (j Just[T]) IsPresent() bool

func (Just[T]) Map ¶

func (j Just[T]) Map(f func(T) T) Optional[T]

func (Just[T]) OrElse ¶

func (j Just[T]) OrElse(other T) T

type Nothing ¶

type Nothing[T any] struct {
}

Optional subtype that contains nothing

func (Nothing[T]) Filter ¶

func (n Nothing[T]) Filter(p Predicate[T]) Optional[T]

func (Nothing[T]) Get ¶

func (n Nothing[T]) Get() (T, error)

func (Nothing[T]) GetError ¶

func (n Nothing[T]) GetError() error

func (Nothing[T]) If ¶

func (n Nothing[T]) If(present func(T), err func(error), nothing func())

func (Nothing[T]) IfError ¶

func (n Nothing[T]) IfError(func(error)) Optional[T]

func (Nothing[T]) IfNothing ¶

func (n Nothing[T]) IfNothing(f func()) Optional[T]

func (Nothing[T]) IfPresent ¶

func (n Nothing[T]) IfPresent(func(T)) Optional[T]

func (Nothing[T]) IsPresent ¶

func (n Nothing[T]) IsPresent() bool

func (Nothing[T]) Map ¶

func (n Nothing[T]) Map(func(T) T) Optional[T]

func (Nothing[T]) OrElse ¶

func (n Nothing[T]) OrElse(other T) T

type Optional ¶

type Optional[T any] interface {
	IsPresent() bool
	IfPresent(func(T)) Optional[T]
	IfError(func(error)) Optional[T]
	IfNothing(func()) Optional[T]
	If(present func(T), err func(error), nothing func())
	Filter(p Predicate[T]) Optional[T]
	OrElse(other T) T
	GetError() error
	Get() (T, error)
	Map(func(T) T) Optional[T]
}

Optional is a wrapper that can contain value, nothing or error.

func Map ¶

func Map[A any, B any](opt Optional[A], f func(A) B) Optional[B]

Applies a function to an optional if the function returns value

func MapErr ¶

func MapErr[A any, B any](opt Optional[A], f func(A) (B, error)) Optional[B]

Applies a function to an optional if the function returns value and error

func Of ¶

func Of[T any](value T) Optional[T]

Constructs an Optional from a value type

func OfError ¶

func OfError[T any](value T, err error) Optional[T]

Constructs an Optional from a value and error (e.g. to wrap a function result)

func OfErrorNullable ¶

func OfErrorNullable[T any](value *T, err error) Optional[*T]

Constructs an Optional from a pointer type (Nothing if value is nil)

func OfNullable ¶

func OfNullable[T any](value *T) Optional[*T]

Constructs an Optional from a pointer type (Nothing if value is nil)

type Predicate ¶

type Predicate[T any] Function[T, bool]

Source Files ¶

View all Source files

optional.go

?	: This menu
/	: Search site
f or F	: Jump to
y or Y	: Canonical URL