option

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v1.0.0-alpha5 Latest Latest
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 Go to latest Published: Oct 31, 2024 License: Apache-2.0 Imports: 12 Imported by: 14

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Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func MapOr 

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

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

func MapOrElse 

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

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

func UndValidate 

func UndValidate[T validate.UndValidator](o Option[T]) error

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 Flatten 

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

Flatten converts Option[Option[T]] into Option[T].

func FromOk 

func FromOk[T any](t T, ok bool) Option[T]

FromOk converts conventional (t T, ok bool) into an option. The options is some if ok is true, none otherwise.

For getting values from maps or slices, instead you may want to use GetMap, GetSlice respectively.

func FromPointer 

func FromPointer[T any](t *T) Option[T]

FromPointer converts *T into Option[T]. If v is nil, it returns a none Option. Otherwise, it returns some Option whose value is the dereferenced v.

If you need to keep t as pointer, use WrapPointer instead.

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]

GetMap gets a value associated with key. If key has a value, the Option is some wrapping the value. Otherwise it returns none Option.

func GetSlice 

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

GetMap gets a value associated with idx. If idx is within interval [0, len(s)), then the Option is some wrapping a value associated to the idx. Otherwise it returns none Option.

func Map 

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

Map 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 WrapPointer 

func WrapPointer[T any](t *T) Option[*T]

WrapPointer converts *T into Option[*T]. The option is some if t is non nil, none otherwise.

If you want t to be dereferenced, use FromPointer instead.

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]) 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]) EqualFunc 

func (o Option[T]) EqualFunc(other Option[T], cmp func(i, j T) bool) bool

EqualFunc tests o and other if both are Some or None. If their state does not match, it returns false immediately. If both have value, it tests equality of their values by cmp.

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]) Iter 

func (o Option[T]) Iter() iter.Seq[T]

Iter returns an iterator over the internal value. If o is some, the iterator yields the Option.Value(), otherwise nothing.

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]) MapOrElseOpt 

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

MapOrElseOpt is like Option.MapOrElse but wraps the returned value into some Option.

func (Option[T]) MapOrOpt 

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

MapOrOpt is like Option.MapOr but wraps the returned value into some Option.

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 deprecated 

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]) UndCheck 

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

func (Option[T]) UndValidate 

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

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]) 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]) Clone 

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

func (Options[T]) Equal 

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

func (Options[T]) EqualFunc 

func (o Options[T]) EqualFunc(opts Options[T], cmp func(i, j T) bool) bool

func (Options[T]) UndCheck 

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

func (Options[T]) UndValidate 

func (o Options[T]) UndValidate() 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.

Source Files

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