option

Documentation

Index

• func MapOrElseOption[T, U any](o Option[T], defaultFn func() U, f func(T) U) U
• func MapOrOption[T, U any](o Option[T], defaultValue U, f func(T) U) U
• type Cloner
• type Equality
• type Option
  • func FlattenOption[T any](o Option[Option[T]]) Option[T]
  • func FromSqlNull[T any](v sql.Null[T]) Option[T]
  • func GetMap[M ~map[K]V, K comparable, V any](m M, key K) Option[V]
  • func GetSlice[S ~[]T, T any](s S, idx int) Option[T]
  • func MapOption[T, U any](o Option[T], f func(T) U) Option[U]
  • func None[T any]() Option[T]
  • func Some[T any](v T) Option[T]
  • func (o Option[T]) And(u Option[T]) Option[T]
  • func (o Option[T]) AndThen(f func(x T) Option[T]) Option[T]
  • func (o Option[T]) CheckUnd() error
  • func (o Option[T]) Clone() Option[T]
  • func (o Option[T]) Equal(other Option[T]) bool
  • func (o Option[T]) Filter(pred func(t T) bool) Option[T]
  • func (o Option[T]) Get() (T, bool)
  • func (o Option[T]) IsNone() bool
  • func (o Option[T]) IsSome() bool
  • func (o Option[T]) IsSomeAnd(f func(T) bool) bool
  • func (o Option[T]) IsZero() bool
  • func (o Option[T]) LogValue() slog.Value
  • func (o Option[T]) Map(f func(v T) T) Option[T]
  • func (o Option[T]) MapOr(defaultValue T, f func(T) T) T
  • func (o Option[T]) MapOrElse(defaultFn func() T, f func(T) T) T
  • func (o Option[T]) MarshalJSON() ([]byte, error)
  • func (o Option[T]) MarshalJSONV2(enc *jsontext.Encoder, opts jsonv2.Options) error
  • func (o Option[T]) MarshalXML(e *xml.Encoder, start xml.StartElement) error
  • func (o Option[T]) Or(u Option[T]) Option[T]
  • func (o Option[T]) OrElse(f func() Option[T]) Option[T]
  • func (o Option[T]) Plain() *T
  • func (o Option[T]) Pointer() *T
  • func (o Option[T]) SqlNull() sql.Null[T]
  • func (o *Option[T]) UnmarshalJSON(data []byte) error
  • func (o *Option[T]) UnmarshalJSONV2(dec *jsontext.Decoder, opts jsonv2.Options) error
  • func (o *Option[T]) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error
  • func (o Option[T]) ValidateUnd() error
  • func (o Option[T]) Value() T
  • func (o Option[T]) Xor(u Option[T]) Option[T]
• type Options
  • func (o Options[T]) CheckUnd() error
  • func (o Options[T]) Clone() Options[T]
  • func (o Options[T]) Equal(opts Options[T]) bool
  • func (o Options[T]) ValidateUnd() error
• type SqlNull
  • func (n *SqlNull[T]) Scan(src any) error
  • func (n SqlNull[T]) Value() (driver.Value, error)

Functions

func MapOrElseOption

func MapOrElseOption[T, U any](o Option[T], defaultFn func() U, f func(T) U) U

MapOrElseOption returns value o's value applied by f if o is some. Otherwise it returns a defaultFn result.

func MapOrOption

func MapOrOption[T, U any](o Option[T], defaultValue U, f func(T) U) U

MapOrOption returns o's value applied by f if o is some. Otherwise it returns defaultValue.

Types

type Cloner

type Cloner[T any] interface {
	Clone() T
}

type Equality

type Equality[T any] interface {
	Equal(T) bool
}

type Option

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

Option represents an optional value.

func FlattenOption

func FlattenOption[T any](o Option[Option[T]]) Option[T]

FlattenOption converts Option[Option[T]] into Option[T].

func FromSqlNull

func FromSqlNull[T any](v sql.Null[T]) Option[T]

func GetMap

func GetMap[M ~map[K]V, K comparable, V any](m M, key K) Option[V]

func GetSlice

func GetSlice[S ~[]T, T any](s S, idx int) Option[T]

func MapOption

func MapOption[T, U any](o Option[T], f func(T) U) Option[U]

MapOption returns Some[U] whose inner value is o's value mapped by f if o is Some. Otherwise it returns None[U].

func None

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

func Some

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

func (Option[T]) And

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

And returns u if o is some, otherwise None[T].

func (Option[T]) AndThen

func (o Option[T]) AndThen(f func(x T) Option[T]) Option[T]

AndThen calls f with value of o if o is some, otherwise returns None[T].

func (Option[T]) CheckUnd

func (o Option[T]) CheckUnd() error

func (Option[T]) Clone

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

func (Option[T]) Equal

func (o Option[T]) Equal(other Option[T]) bool

Equal implements Equality[Option[T]].

Equal tests o and other if both are Some or None. If both have value, it tests equality of their values.

Equal panics If T or dynamic type of T is not comparable.

Option is comparable if T is comparable. Equal only exists for cases where T needs a special Equal method (e.g. time.Time, slice based types)

Equal first checks if T implements Equality[T], then also for *T. If it does not, then Equal compares by the `==` comparison operator.

func (Option[T]) Filter

func (o Option[T]) Filter(pred func(t T) bool) Option[T]

Filter returns o if o is some and calling pred against o's value returns true. Otherwise it returns None[T].

func (Option[T]) Get

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

func (Option[T]) IsNone

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

func (Option[T]) IsSome

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

func (Option[T]) IsSomeAnd

func (o Option[T]) IsSomeAnd(f func(T) bool) bool

IsSomeAnd returns true if o is some and calling f with value of o returns true. Otherwise it returns false.

func (Option[T]) IsZero

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

func (Option[T]) LogValue

func (o Option[T]) LogValue() slog.Value

LogValue implements slog.LogValuer

func (Option[T]) Map

func (o Option[T]) Map(f func(v T) T) Option[T]

Map returns Option[T] whose inner value is o's value mapped by f if o is some. Otherwise it returns None[T].

func (Option[T]) MapOr

func (o Option[T]) MapOr(defaultValue T, f func(T) T) T

MapOr returns value o's value applied by f if o is some. Otherwise it returns defaultValue.

func (Option[T]) MapOrElse

func (o Option[T]) MapOrElse(defaultFn func() T, f func(T) T) T

MapOrElse returns value o's value applied by f if o is some. Otherwise it returns a defaultFn result.

func (Option[T]) MarshalJSON

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

func (Option[T]) MarshalJSONV2

func (o Option[T]) MarshalJSONV2(enc *jsontext.Encoder, opts jsonv2.Options) error

func (Option[T]) MarshalXML

func (o Option[T]) MarshalXML(e *xml.Encoder, start xml.StartElement) error

func (Option[T]) Or

func (o Option[T]) Or(u Option[T]) Option[T]

Or returns o if o is some, otherwise u.

func (Option[T]) OrElse

func (o Option[T]) OrElse(f func() Option[T]) Option[T]

OrElse returns o if o is some, otherwise calls f and returns the result.

func (Option[T]) Plain

func (o Option[T]) Plain() *T

Plain transforms o to *T, the plain conventional Go representation of an optional value. The value is copied by assignment before returned from Plain.

Deprecated: use Pointer instead.

func (Option[T]) Pointer

func (o Option[T]) Pointer() *T

Pointer transforms o to *T, the plain conventional Go representation of an optional value. The value is copied by assignment before returned from Pointer.

func (Option[T]) SqlNull

func (o Option[T]) SqlNull() sql.Null[T]

func (*Option[T]) UnmarshalJSON

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

func (*Option[T]) UnmarshalJSONV2

func (o *Option[T]) UnmarshalJSONV2(dec *jsontext.Decoder, opts jsonv2.Options) error

func (*Option[T]) UnmarshalXML

func (o *Option[T]) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error

func (Option[T]) ValidateUnd

func (o Option[T]) ValidateUnd() error

func (Option[T]) Value

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

Value returns its internal as T. T would be zero value if o is None.

func (Option[T]) Xor

func (o Option[T]) Xor(u Option[T]) Option[T]

Xor returns o or u if either is some. If both are some or both none, it returns None[T].

type Options

type Options[T any] []Option[T]

func (Options[T]) CheckUnd

func (o Options[T]) CheckUnd() error

func (Options[T]) Clone

func (o Options[T]) Clone() Options[T]

func (Options[T]) Equal

func (o Options[T]) Equal(opts Options[T]) bool

func (Options[T]) ValidateUnd

func (o Options[T]) ValidateUnd() error

type SqlNull

type SqlNull[T any] struct {
	Option[T]
}

SqlNull[T] adapts Option[T] to sql.Scanner and driver.Valuer.

func (*SqlNull[T]) Scan

func (n *SqlNull[T]) Scan(src any) error

Scan implements sql.Scanner.

If T or *T implements sql.Scanner, the implementation is used. Otherwise, SqlNull[T] falls back to sql.Null[T] as sql.Scanner.

func (SqlNull[T]) Value

func (n SqlNull[T]) Value() (driver.Value, error)

Value implements driver.Valuer.

If T or *T implements driver.Valuer, the implementation is used. In this respect, T should not be a pointer type or Option[T] should not store nil value. Otherwise, SqlNull[T] falls back to sql.Null[T] as driver.Valuer.