README
¶
opt - handling optional data
This package provides types and functions for dealing with optional data.
All types implement json.Marshaler, json.Unmarshaler, driver.Valuer and sql.Scanner interfaces.
Types in textopt package additionally implement encoding.TextMarshaler and encoding.TextUnmarshaler interfaces.
Null[T]
Null represents an optional value that becomes valid when it is assigned a value other than nil.
var v opt.Null[string]
json.Unmarshal(&v, []byte(`null`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "" false
json.Unmarshal(&v, []byte(`""`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "" true
json.Unmarshal(&v, []byte(`"123"`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "123" true
Zero[T]
Zero represents an optional value that becomes valid when it is assigned a value other than nil or zero.
Value is considered zero according to rules:
- If type T has an
IsZero() boolmethod, that returns true for the value. - Otherwise, the value is zero if it is the zero value for type T.
var v opt.Zero[string]
json.Unmarshal(&v, []byte(`null`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "" false
json.Unmarshal(&v, []byte(`""`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "" false
json.Unmarshal(&v, []byte(`"123"`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "123" true
Undefined[T]
Undefined represents an optional value that becomes valid when it is assigned any value.
var v opt.Undefined[string]
json.Unmarshal(&v, []byte(`null`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "" true
json.Unmarshal(&v, []byte(`""`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "" true
json.Unmarshal(&v, []byte(`"123"`))
fmt.Printf("%q %v\n", v.V, v.Valid) // output: "123" true
Documentation
¶
Overview ¶
Package opt provides types and functions for dealing with optional data.
Index ¶
- type Empty
- func EmptyFrom[T comparable](value T) Empty[T]
- func EmptyFromFunc[T comparable, U any](value *U, f func(U) T) Empty[T]
- func EmptyFromFuncPtr[T comparable, U any](value *U, f func(*U) T) Empty[T]
- func EmptyFromPtr[T comparable](value *T) Empty[T]
- func NewEmpty[T comparable](value T, valid bool) Empty[T]
- func (v Empty[T]) Get() (value T, ok bool)
- func (v Empty[T]) IsZero() bool
- func (v Empty[T]) MarshalJSON() ([]byte, error)
- func (v Empty[T]) Or(value T) T
- func (v *Empty[T]) Ptr() *T
- func (v *Empty[T]) Reset()
- func (v *Empty[T]) Scan(value any) error
- func (v *Empty[T]) Set(value T)
- func (v Empty[T]) ToSQL() sql.Null[T]
- func (v *Empty[T]) UnmarshalJSON(data []byte) error
- func (v Empty[T]) Value() (driver.Value, error)
- type IsZeroer
- type Null
- func (v Null[T]) Get() (value T, ok bool)
- func (v Null[T]) IsZero() bool
- func (v Null[T]) MarshalJSON() ([]byte, error)
- func (v Null[T]) Or(value T) T
- func (v *Null[T]) Ptr() *T
- func (v *Null[T]) Reset()
- func (v *Null[T]) Scan(value any) error
- func (v *Null[T]) Set(value T)
- func (v Null[T]) ToSQL() sql.Null[T]
- func (v *Null[T]) UnmarshalJSON(data []byte) error
- func (v Null[T]) Value() (driver.Value, error)
- type Undefined
- func NewUndefined[T any](value T, valid bool) Undefined[T]
- func UndefinedFrom[T any](value T) Undefined[T]
- func UndefinedFromFunc[T, U any](value *U, f func(U) T) Undefined[T]
- func UndefinedFromFuncPtr[T, U any](value *U, f func(*U) T) Undefined[T]
- func UndefinedFromPtr[T any](value *T) Undefined[T]
- func (v Undefined[T]) Get() (value T, ok bool)
- func (v Undefined[T]) IsZero() bool
- func (v Undefined[T]) MarshalJSON() ([]byte, error)
- func (v Undefined[T]) Or(value T) T
- func (v *Undefined[T]) Ptr() *T
- func (v *Undefined[T]) Reset()
- func (v *Undefined[T]) Scan(value any) error
- func (v *Undefined[T]) Set(value T)
- func (v Undefined[T]) ToSQL() sql.Null[T]
- func (v *Undefined[T]) UnmarshalJSON(data []byte) error
- func (v Undefined[T]) Value() (driver.Value, error)
- type Zero
- func (v Zero[T]) Get() (value T, ok bool)
- func (v Zero[T]) IsZero() bool
- func (v Zero[T]) MarshalJSON() ([]byte, error)
- func (v Zero[T]) Or(value T) T
- func (v *Zero[T]) Ptr() *T
- func (v *Zero[T]) Reset()
- func (v *Zero[T]) Scan(value any) error
- func (v *Zero[T]) Set(value T)
- func (v Zero[T]) ToSQL() sql.Null[T]
- func (v *Zero[T]) UnmarshalJSON(data []byte) error
- func (v Zero[T]) Value() (driver.Value, error)
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Empty ¶ added in v0.4.0
type Empty[T comparable] struct { V T Valid bool }
Empty represents an optional value that becomes valid when it is assigned a value other than nil or zero. Value is considered zero if it is the zero value for type T.
func EmptyFrom ¶ added in v0.4.0
func EmptyFrom[T comparable](value T) Empty[T]
func EmptyFromFunc ¶ added in v0.4.0
func EmptyFromFunc[T comparable, U any](value *U, f func(U) T) Empty[T]
func EmptyFromFuncPtr ¶ added in v0.4.0
func EmptyFromFuncPtr[T comparable, U any](value *U, f func(*U) T) Empty[T]
func EmptyFromPtr ¶ added in v0.4.0
func EmptyFromPtr[T comparable](value *T) Empty[T]
func NewEmpty ¶ added in v0.4.0
func NewEmpty[T comparable](value T, valid bool) Empty[T]
func (Empty[T]) MarshalJSON ¶ added in v0.4.0
func (*Empty[T]) UnmarshalJSON ¶ added in v0.4.0
type IsZeroer ¶ added in v0.4.0
type IsZeroer interface {
IsZero() bool
}
IsZeroer represents types that can report whether their value is zero.
type Null ¶
Null represents an optional value that becomes valid when it is assigned a value other than nil.
func NullFromFunc ¶
func NullFromFuncPtr ¶
func NullFromPtr ¶
func (Null[T]) MarshalJSON ¶
func (*Null[T]) UnmarshalJSON ¶
type Undefined ¶
Undefined represents an optional value that becomes valid when it is assigned any value.
func NewUndefined ¶
func UndefinedFrom ¶
func UndefinedFromFunc ¶
func UndefinedFromFuncPtr ¶
func UndefinedFromPtr ¶
func (Undefined[T]) MarshalJSON ¶
func (*Undefined[T]) UnmarshalJSON ¶
type Zero ¶
Zero represents an optional value that becomes valid when it is assigned a value other than nil or zero. Value is considered zero if IsZero method of type T returns true for the value.
Source Files
Directories