reflect

Documentation

Index

• Constants
• func Copy(dst, src Value) int
• func DeepEqual(x, y interface{}) bool
• func Swapper(slice interface{}) func(i, j int)
• type ChanDir
• type Kind
• type MapIter
  • func (it *MapIter) Key() Value
  • func (it *MapIter) Next() bool
  • func (iter *MapIter) Reset(v Value)
  • func (it *MapIter) Value() Value
• type Method
• type SelectCase
• type SelectDir
• type SliceHeader
• type StringHeader
• type StructField
  • func VisibleFields(t Type) []StructField
  • func (f StructField) IsExported() bool
• type StructTag
• type Type
  • func PointerTo(t Type) Type
  • func PtrTo(t Type) Type
  • func TypeFor[T any]() Type
  • func TypeOf(i interface{}) Type
• type Value
  • func Append(v Value, x ...Value) Value
  • func AppendSlice(s, t Value) Value
  • func Indirect(v Value) Value
  • func MakeFunc(typ Type, fn func(args []Value) (results []Value)) Value
  • func MakeMap(typ Type) Value
  • func MakeMapWithSize(typ Type, n int) Value
  • func MakeSlice(typ Type, len, cap int) Value
  • func New(typ Type) Value
  • func NewAt(typ Type, p unsafe.Pointer) Value
  • func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool)
  • func ValueOf(i interface{}) Value
  • func Zero(typ Type) Value
  • func (v Value) Addr() Value
  • func (v Value) Call(in []Value) []Value
  • func (v Value) CallSlice(in []Value) []Value
  • func (v Value) CanConvert(t Type) bool
  • func (v Value) Close()
  • func (v Value) Convert(t Type) Value
  • func (v Value) Elem() Value
  • func (v Value) Equal(u Value) bool
  • func (v Value) Field(i int) Value
  • func (v Value) FieldByIndex(index []int) Value
  • func (v Value) FieldByIndexErr(index []int) (Value, error)
  • func (v Value) FieldByName(name string) Value
  • func (v Value) FieldByNameFunc(match func(string) bool) Value
  • func (v Value) Index(i int) Value
  • func (v Value) MapIndex(key Value) Value
  • func (v Value) MapKeys() []Value
  • func (v Value) MapRange() *MapIter
  • func (v Value) Method(i int) Value
  • func (v Value) MethodByName(name string) Value
  • func (v Value) Recv() (x Value, ok bool)
  • func (v Value) Send(x Value)
  • func (v Value) Seq() iter.Seq[Value]
  • func (v Value) Seq2() iter.Seq2[Value, Value]
  • func (v Value) Set(x Value)
  • func (v Value) SetIterKey(iter *MapIter)
  • func (v Value) SetIterValue(iter *MapIter)
  • func (v Value) SetMapIndex(key, elem Value)
  • func (v Value) Slice(i, j int) Value
  • func (v Value) Slice3(i, j, k int) Value
  • func (v Value) Type() Type
• type ValueError

Constants

const (
	RecvDir = reflectlite.RecvDir
	SendDir = reflectlite.SendDir
	BothDir = reflectlite.BothDir
)

const Ptr = reflectlite.Ptr

Functions

func Copy

func Copy(dst, src Value) int

Copy copies the contents of src into dst until either dst has been filled or src has been exhausted.

func DeepEqual

func DeepEqual(x, y interface{}) bool

func Swapper

func Swapper(slice interface{}) func(i, j int)

Types

type ChanDir

type ChanDir = reflectlite.ChanDir

type Kind

type Kind = reflectlite.Kind

const (
	Invalid       Kind = reflectlite.Invalid
	Bool          Kind = reflectlite.Bool
	Int           Kind = reflectlite.Int
	Int8          Kind = reflectlite.Int8
	Int16         Kind = reflectlite.Int16
	Int32         Kind = reflectlite.Int32
	Int64         Kind = reflectlite.Int64
	Uint          Kind = reflectlite.Uint
	Uint8         Kind = reflectlite.Uint8
	Uint16        Kind = reflectlite.Uint16
	Uint32        Kind = reflectlite.Uint32
	Uint64        Kind = reflectlite.Uint64
	Uintptr       Kind = reflectlite.Uintptr
	Float32       Kind = reflectlite.Float32
	Float64       Kind = reflectlite.Float64
	Complex64     Kind = reflectlite.Complex64
	Complex128    Kind = reflectlite.Complex128
	Array         Kind = reflectlite.Array
	Chan          Kind = reflectlite.Chan
	Func          Kind = reflectlite.Func
	Interface     Kind = reflectlite.Interface
	Map           Kind = reflectlite.Map
	Pointer       Kind = reflectlite.Pointer
	Slice         Kind = reflectlite.Slice
	String        Kind = reflectlite.String
	Struct        Kind = reflectlite.Struct
	UnsafePointer Kind = reflectlite.UnsafePointer
)

type MapIter

type MapIter reflectlite.MapIter

func (*MapIter) Key

func (it *MapIter) Key() Value

func (*MapIter) Next

func (it *MapIter) Next() bool

func (*MapIter) Reset

func (iter *MapIter) Reset(v Value)

func (*MapIter) Value

func (it *MapIter) Value() Value

type Method

type Method struct {
	// Name is the method name.
	Name string

	// PkgPath is the package path that qualifies a lower case (unexported)
	// method name. It is empty for upper case (exported) method names.
	// The combination of PkgPath and Name uniquely identifies a method
	// in a method set.
	// See https://golang.org/ref/spec#Uniqueness_of_identifiers
	PkgPath string

	Type  Type  // method type
	Func  Value // func with receiver as first argument
	Index int   // index for Type.Method
}

Method represents a single method.

type SelectCase

type SelectCase struct {
	Dir  SelectDir // direction of case
	Chan Value     // channel to use (for send or receive)
	Send Value     // value to send (for send)
}

type SelectDir

type SelectDir int

const (
	SelectSend    SelectDir // case Chan <- Send
	SelectRecv              // case <-Chan:
	SelectDefault           // default
)

type SliceHeader

type SliceHeader struct {
	Data uintptr
	Len  intw
	Cap  intw
}

Deprecated: Use unsafe.Slice or unsafe.SliceData instead.

type StringHeader

type StringHeader struct {
	Data uintptr
	Len  intw
}

Deprecated: Use unsafe.String or unsafe.StringData instead.

type StructField

type StructField struct {
	// Name indicates the field name.
	Name string

	// PkgPath is the package path where the struct containing this field is
	// declared for unexported fields, or the empty string for exported fields.
	PkgPath string

	Type      Type
	Tag       StructTag // field tag string
	Offset    uintptr
	Index     []int // index sequence for Type.FieldByIndex
	Anonymous bool
}

A StructField describes a single field in a struct. This must be kept in sync with reflectlite.StructField.

func VisibleFields

func VisibleFields(t Type) []StructField

func (StructField) IsExported

func (f StructField) IsExported() bool

IsExported reports whether the field is exported.

type StructTag

type StructTag = reflectlite.StructTag

type Type

type Type interface {

	// Align returns the alignment in bytes of a value of
	// this type when allocated in memory.
	Align() int

	// FieldAlign returns the alignment in bytes of a value of
	// this type when used as a field in a struct.
	FieldAlign() int

	// Method returns the i'th method in the type's method set.
	// It panics if i is not in the range [0, NumMethod()).
	//
	// For a non-interface type T or *T, the returned Method's Type and Func
	// fields describe a function whose first argument is the receiver.
	//
	// For an interface type, the returned Method's Type field gives the
	// method signature, without a receiver, and the Func field is nil.
	//
	// Only exported methods are accessible and they are sorted in
	// lexicographic order.
	Method(int) Method

	// MethodByName returns the method with that name in the type's
	// method set and a boolean indicating if the method was found.
	//
	// For a non-interface type T or *T, the returned Method's Type and Func
	// fields describe a function whose first argument is the receiver.
	//
	// For an interface type, the returned Method's Type field gives the
	// method signature, without a receiver, and the Func field is nil.
	MethodByName(string) (Method, bool)

	// NumMethod returns the number of exported methods in the type's method set.
	NumMethod() int

	// Name returns the type's name within its package for a defined type.
	// For other (non-defined) types it returns the empty string.
	Name() string

	// PkgPath returns a defined type's package path, that is, the import path
	// that uniquely identifies the package, such as "encoding/base64".
	// If the type was predeclared (string, error) or not defined (*T, struct{},
	// []int, or A where A is an alias for a non-defined type), the package path
	// will be the empty string.
	PkgPath() string

	// Size returns the number of bytes needed to store
	// a value of the given type; it is analogous to unsafe.Sizeof.
	Size() uintptr

	// String returns a string representation of the type.
	// The string representation may use shortened package names
	// (e.g., base64 instead of "encoding/base64") and is not
	// guaranteed to be unique among types. To test for type identity,
	// compare the Types directly.
	String() string

	// Kind returns the specific kind of this type.
	Kind() Kind

	// Implements reports whether the type implements the interface type u.
	Implements(u Type) bool

	// AssignableTo reports whether a value of the type is assignable to type u.
	AssignableTo(u Type) bool

	// ConvertibleTo reports whether a value of the type is convertible to type u.
	ConvertibleTo(u Type) bool

	// Comparable reports whether values of this type are comparable.
	Comparable() bool

	// Bits returns the size of the type in bits.
	// It panics if the type's Kind is not one of the
	// sized or unsized Int, Uint, Float, or Complex kinds.
	Bits() int

	// ChanDir returns a channel type's direction.
	// It panics if the type's Kind is not Chan.
	ChanDir() ChanDir

	// IsVariadic reports whether a function type's final input parameter
	// is a "..." parameter. If so, t.In(t.NumIn() - 1) returns the parameter's
	// implicit actual type []T.
	//
	// For concreteness, if t represents func(x int, y ... float64), then
	//
	//	t.NumIn() == 2
	//	t.In(0) is the reflect.Type for "int"
	//	t.In(1) is the reflect.Type for "[]float64"
	//	t.IsVariadic() == true
	//
	// IsVariadic panics if the type's Kind is not Func.
	IsVariadic() bool

	// Elem returns a type's element type.
	// It panics if the type's Kind is not Array, Chan, Map, Pointer, or Slice.
	Elem() Type

	// Field returns a struct type's i'th field.
	// It panics if the type's Kind is not Struct.
	// It panics if i is not in the range [0, NumField()).
	Field(i int) StructField

	// FieldByIndex returns the nested field corresponding
	// to the index sequence. It is equivalent to calling Field
	// successively for each index i.
	// It panics if the type's Kind is not Struct.
	FieldByIndex(index []int) StructField

	// FieldByName returns the struct field with the given name
	// and a boolean indicating if the field was found.
	FieldByName(name string) (StructField, bool)

	// FieldByNameFunc returns the struct field with a name
	// that satisfies the match function and a boolean indicating if
	// the field was found.
	//
	// FieldByNameFunc considers the fields in the struct itself
	// and then the fields in any embedded structs, in breadth first order,
	// stopping at the shallowest nesting depth containing one or more
	// fields satisfying the match function. If multiple fields at that depth
	// satisfy the match function, they cancel each other
	// and FieldByNameFunc returns no match.
	// This behavior mirrors Go's handling of name lookup in
	// structs containing embedded fields.
	FieldByNameFunc(match func(string) bool) (StructField, bool)

	// In returns the type of a function type's i'th input parameter.
	// It panics if the type's Kind is not Func.
	// It panics if i is not in the range [0, NumIn()).
	In(i int) Type

	// Key returns a map type's key type.
	// It panics if the type's Kind is not Map.
	Key() Type

	// Len returns an array type's length.
	// It panics if the type's Kind is not Array.
	Len() int

	// NumField returns a struct type's field count.
	// It panics if the type's Kind is not Struct.
	NumField() int

	// NumIn returns a function type's input parameter count.
	// It panics if the type's Kind is not Func.
	NumIn() int

	// NumOut returns a function type's output parameter count.
	// It panics if the type's Kind is not Func.
	NumOut() int

	// Out returns the type of a function type's i'th output parameter.
	// It panics if the type's Kind is not Func.
	// It panics if i is not in the range [0, NumOut()).
	Out(i int) Type

	// OverflowComplex reports whether the complex128 x cannot be represented by type t.
	// It panics if t's Kind is not Complex64 or Complex128.
	OverflowComplex(x complex128) bool

	// OverflowFloat reports whether the float64 x cannot be represented by type t.
	// It panics if t's Kind is not Float32 or Float64.
	OverflowFloat(x float64) bool

	// OverflowInt reports whether the int64 x cannot be represented by type t.
	// It panics if t's Kind is not Int, Int8, Int16, Int32, or Int64.
	OverflowInt(x int64) bool

	// OverflowUint reports whether the uint64 x cannot be represented by type t.
	// It panics if t's Kind is not Uint, Uintptr, Uint8, Uint16, Uint32, or Uint64.
	OverflowUint(x uint64) bool

	// CanSeq reports whether a [Value] with this type can be iterated over using [Value.Seq].
	CanSeq() bool

	// CanSeq2 reports whether a [Value] with this type can be iterated over using [Value.Seq2].
	CanSeq2() bool
}

Type is the representation of a Go type.

Not all methods apply to all kinds of types. Restrictions, if any, are noted in the documentation for each method. Use the Kind method to find out the kind of type before calling kind-specific methods. Calling a method inappropriate to the kind of type causes a run-time panic.

Type values are comparable, such as with the == operator, so they can be used as map keys. Two Type values are equal if they represent identical types.

func PointerTo

func PointerTo(t Type) Type

func PtrTo

func PtrTo(t Type) Type

func TypeFor

func TypeFor[T any]() Type

func TypeOf

func TypeOf(i interface{}) Type

type Value

type Value struct {
	reflectlite.Value
}

func Append

func Append(v Value, x ...Value) Value

Append appends the values x to a slice s and returns the resulting slice. As in Go, each x's value must be assignable to the slice's element type.

func AppendSlice

func AppendSlice(s, t Value) Value

AppendSlice appends a slice t to a slice s and returns the resulting slice. The slices s and t must have the same element type.

func Indirect

func Indirect(v Value) Value

func MakeFunc

func MakeFunc(typ Type, fn func(args []Value) (results []Value)) Value

func MakeMap

func MakeMap(typ Type) Value

MakeMap creates a new map with the specified type.

func MakeMapWithSize

func MakeMapWithSize(typ Type, n int) Value

MakeMapWithSize creates a new map with the specified type and initial space for approximately n elements.

func MakeSlice

func MakeSlice(typ Type, len, cap int) Value

func New

func New(typ Type) Value

New is the reflect equivalent of the new(T) keyword, returning a pointer to a new value of the given type.

func NewAt

func NewAt(typ Type, p unsafe.Pointer) Value

func Select

func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool)

func ValueOf

func ValueOf(i interface{}) Value

func Zero

func Zero(typ Type) Value

func (Value) Addr

func (v Value) Addr() Value

func (Value) Call

func (v Value) Call(in []Value) []Value

func (Value) CallSlice

func (v Value) CallSlice(in []Value) []Value

func (Value) CanConvert

func (v Value) CanConvert(t Type) bool

func (Value) Close

func (v Value) Close()

func (Value) Convert

func (v Value) Convert(t Type) Value

func (Value) Elem

func (v Value) Elem() Value

func (Value) Equal

func (v Value) Equal(u Value) bool

func (Value) Field

func (v Value) Field(i int) Value

Field returns the value of the i'th field of this struct.

func (Value) FieldByIndex

func (v Value) FieldByIndex(index []int) Value

FieldByIndex returns the nested field corresponding to index.

func (Value) FieldByIndexErr

func (v Value) FieldByIndexErr(index []int) (Value, error)

FieldByIndexErr returns the nested field corresponding to index.

func (Value) FieldByName

func (v Value) FieldByName(name string) Value

func (Value) FieldByNameFunc

func (v Value) FieldByNameFunc(match func(string) bool) Value

func (Value) Index

func (v Value) Index(i int) Value

func (Value) MapIndex

func (v Value) MapIndex(key Value) Value

func (Value) MapKeys

func (v Value) MapKeys() []Value

func (Value) MapRange

func (v Value) MapRange() *MapIter

func (Value) Method

func (v Value) Method(i int) Value

func (Value) MethodByName

func (v Value) MethodByName(name string) Value

func (Value) Recv

func (v Value) Recv() (x Value, ok bool)

func (Value) Send

func (v Value) Send(x Value)

func (Value) Seq

func (v Value) Seq() iter.Seq[Value]

Seq returns an iter.Seq[Value] that loops over the elements of v. If v's kind is Func, it must be a function that has no results and that takes a single argument of type func(T) bool for some type T. If v's kind is Pointer, the pointer element type must have kind Array. Otherwise v's kind must be Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr, Array, Chan, Map, Slice, or String.

func (Value) Seq2

func (v Value) Seq2() iter.Seq2[Value, Value]

Seq2 returns an iter.Seq2[Value, Value] that loops over the elements of v. If v's kind is Func, it must be a function that has no results and that takes a single argument of type func(K, V) bool for some type K, V. If v's kind is Pointer, the pointer element type must have kind Array. Otherwise v's kind must be Array, Map, Slice, or String.

func (Value) Set

func (v Value) Set(x Value)

func (Value) SetIterKey

func (v Value) SetIterKey(iter *MapIter)

func (Value) SetIterValue

func (v Value) SetIterValue(iter *MapIter)

func (Value) SetMapIndex

func (v Value) SetMapIndex(key, elem Value)

func (Value) Slice

func (v Value) Slice(i, j int) Value

func (Value) Slice3

func (v Value) Slice3(i, j, k int) Value

func (Value) Type

func (v Value) Type() Type

type ValueError

type ValueError = reflectlite.ValueError