This is a creation in Article, where the information may have evolved or changed.
Reflective packets have an interface: type, and a struct value;
Type interface
The Commontype type implements the type interface, and the following are the various types of relationships in type
- Commontype>uncommontype>method
- Arraytype|chantype|functype|interfacetype|maptype|ptrtype|slicetype >commontype
- Ptrmap>n*commontype
Other structures
Method structure
Methodbyname () and method () return this type
Type Method struct {Name stringpkgpath stringtype Type //Method typefunc Value//func with receiver as F irst argumentindex int //index for Type.method}
Structfield structure
Field () and Fieldbyindex (), and Fieldbyname (), FIELDBYNAMEFUNC returns the type
Type Structfield struct {name *string //nil for embedded Fieldspkgpath *string //nil for exported Names; oth Erwise Import Pathtyp *runtimetype//type of Fieldtag *string //nil If no tagoffset uintptr //Byte Offset of field within struct}
Reflects the type of a variable, essentially converting the pointer of the variable to a commontype pointer
- First, a pointer to a variable is converted to the pointer type by unsafe package
- Then convert the pointer type to the *emptyinterface type and use the * expression to pass its Emptyinterface value to Eface
- Asserts whether the value of Eface.typ is a pointer type of Commontype and returns its value if it is
Func ToType (P *runtimetype) Type {if p = = Nil {return Nil}return (*p). *commontype)}func TypeOf (i interface{}) Type {eface: = * (*emptyinterface) (unsafe. Pointer (&i)) return ToType (Eface.typ)}
Introduction to type Functions
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Func chanof (dir chandir, T type) type
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Return Channel type
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Func mapof (key, Elem type) type
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Return to map type
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Func Ptrto (t type) type
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Return pointer type
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Func sliceof (t type) type
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return Slice Type
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Func TypeOf (i interface{}) Type
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reflective variable type, it is best not to pass the pointer directly. Otherwise something will not be emitted. For example, name ()
Type method Introduction
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Func (t *commontype) Align () int
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The alignment of the
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bytes returned when the type is in content allocation
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Func (t *commontype) fieldalign () int
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when the type is a field of a structure, his byte alignment
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Func (t *commontype) method (i int) (M method)
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returns a method type by shaping the index, reflection type
Type B struct {c stringb bytea Int}func (b b) test () {}func main () {B: = b{}fmt. Println (reflect. TypeOf (b). Method (0). Name) //test}
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Func (t *commontype) methodbyname (name string) (M Method, OK BOOL)
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determines whether the type has the method by the method name, returns the method if it exists, and returns an OK value of true
Type B struct {c stringb bytea Int}func (b b) test () {}func main () {b: = new (b) m, _: = Reflect. TypeOf (b). Methodbyname ("Test") fmt. Println (M.pkgpath)}
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Func (t *commontype) nummethod () int
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returns the number of methods owned by this type
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Func (t *commontype) Name () string
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returns the name of the type, if the anonymous type will return a null character channeling, and if it is a pointer, nothing
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Func (t *commontype) Pkgpath () string
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returns the path of the package that contains the type, and if it is a pointer, what the wood has
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Func (t *commontype) Size () uintptr
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returns the size of the type
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Func (t *commontype) string () string
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return type of character channeling name
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Func (t *commontype) Kind () Kind
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returns the special kind of this type, (Struct,ptr,func, etc.)
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Func (t *commontype) Implements (U Type) bool
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determines whether the type implements the U interface. Note You must not be nil and is an interface
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Func (t *commontype) assignableto (U Type) bool
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determines whether the type can be assigned to the U type
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Func (t *commontype) Bits () int
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The
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use of the reflection type of bytes, if not the Int,uint,float,complex species will produce panic
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Func (t *commontype) Chandir () Chandir
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reflected Channel directory
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Func (t *commontype) isvariadic () bool
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determine if the function has a mutable parameter (...)
Type B struct {c stringb bytea Int}func (b b) test () {}func test (a ... int) {}func main () {FMT. Println (reflect. TypeOf (Test). Isvariadic ()) //truefmt. Println (reflect. TypeOf (b.test). Isvariadic ()) //false}
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Func (t *commontype) Elem () Type
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Returns a type of element type, the kind of non-array,chan,map,ptr,slice will generate panic
Type B struct {c stringb bytea Int}func (b b) test () {}func main () {B: = &b{}fmt. Println (reflect. TypeOf (b). Elem ()) //main. B
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Func (t *commontype) Field (i int) Structfield
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returns a structure field based on the index, with a value of Structfield type
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Func (t *commontype) fieldbyindex (index []int) Structfield
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returns the field structure of a nested type.
Type A struct {a intb Bytec string}type b struct {Ac stringb bytea int}func (b b) test () {}func main () {b: = B{}index: = [ ]int{0, 1}fmt. Println (reflect. TypeOf (b). Fieldbyindex (Index). Name) //b}
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Func (t *commontype) fieldbyname (name string) (Structfield, BOOL)
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reflect the field type, depending on the field name
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Func (t *commontype) Fieldbynamefunc (match func (string) bool) (Structfield, BOOL)
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.... I don't understand
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Type B struct {c stringb bytea Int}func Test (a string) bool {return True}func main () {b: = b{}fmt. Println (reflect. TypeOf (b). Fieldbynamefunc (test)) //{ 0 [] false} false}
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Func (t *commontype) in (i int) Type
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The I parameter of the reflection function type
Func Test (a string) bool {return True}func main () {FMT. Println (reflect. TypeOf (Test). In (0))}
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Func (t *commontype) Key () Type
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The type of key that reflects the map type, if not map, generates panic.
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Func (t *commontype) Len () int
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Reflects the length of the array type, which can cause panic if it is not an array
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Func (t *commontype) Numfield () int
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Reflects the number of fields in a struct, which can cause panic if not a struct.
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Func (t *commontype) numin () int
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Reflection of the number of input parameters of a func, if not the function will cause panic.
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Func (t *commontype) numout () int
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The number of returned results of a reflection function, a stake is not a function that creates panic.
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Func (t *commontype) out (i int) Type
The
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reflection function returns the type of I of the result and, if not the function, creates a panic, and if not in the range [0, Numout ()], it can also cause panic
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Off-topic: Declaring a variable whose value is an anonymous structure
Type T struct {}var T Tvar t struct {}
