optionext

Documentation

Index

• type Option
  • func None[T any]() Option[T]
  • func Some[T any](value T) Option[T]
  • func (o Option[T]) And(fn func(T) T) Option[T]
  • func (o Option[T]) AndThen(fn func(T) Option[T]) Option[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 any) error
  • func (o *Option[T]) UnmarshalJSON(data []byte) error
  • func (o Option[T]) Unwrap() T
  • func (o Option[T]) UnwrapOr(value T) T
  • func (o Option[T]) UnwrapOrDefault() T
  • func (o Option[T]) UnwrapOrElse(fn func() T) T
  • func (o Option[T]) Value() (driver.Value, error)

Types

type Option

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

Option represents a values that represents a values existence.

nil is usually used on Go however this has two problems: 1. Checking if the return values is nil is NOT enforced and can lead to panics. 2. Using nil is not good enough when nil itself is a valid value.

This implements the sql.Scanner interface and can be used as a sql value for reading and writing. It supports: - String - Bool - Uint8 - Float64 - Int16 - Int32 - Int64 - interface{}/any - time.Time - Struct - when type is convertable to []byte and assumes JSON. - Slice - when type is convertable to []byte and assumes JSON. - Map types - when type is convertable to []byte and assumes JSON.

This also implements the `json.Marshaler` and `json.Unmarshaler` interfaces. The only caveat is a None value will result in a JSON `null` value. there is no way to hook into the std library to make `omitempty` not produce any value at this time.

func None

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

None creates an empty Option that represents no values.

func Some

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

Some creates a new Option with the given values.

func (Option[T]) And

func (o Option[T]) And(fn func(T) T) Option[T]

And calls the provided function with the contained value if the option is Some, returns the None value otherwise.

func (Option[T]) AndThen

func (o Option[T]) AndThen(fn func(T) Option[T]) Option[T]

AndThen calls the provided function with the contained value if the option is Some, returns the None value otherwise.

This differs from `And` in that the provided function returns an Option[T] allowing changing of the Option value itself.

func (Option[T]) IsNone

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

IsNone returns true if the option is empty.

func (Option[T]) IsSome

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

IsSome returns true if the option is not empty.

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 any) error

Scan implements the sql.Scanner interface.

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() T

Unwrap returns the values if the option is not empty or panics.

func (Option[T]) UnwrapOr

func (o Option[T]) UnwrapOr(value T) T

UnwrapOr returns the contained `Some` value or provided default value.

Arguments passed to `UnwrapOr` are eagerly evaluated; if you are passing the result of a function call, look to use `UnwrapOrElse`, which can be lazily evaluated.

func (Option[T]) UnwrapOrDefault

func (o Option[T]) UnwrapOrDefault() T

UnwrapOrDefault returns the contained `Some` value or the default value of the type T.

func (Option[T]) UnwrapOrElse

func (o Option[T]) UnwrapOrElse(fn func() T) T

UnwrapOrElse returns the contained `Some` value or computes it from a provided function.

func (Option[T]) Value

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

Value implements the driver.Valuer interface.

This honours the `driver.Valuer` interface if the value implements it. It also supports custom types of the std types and treats all else as []byte