golang generics 代码
文件路径：/src/go/doc/testdata/generics.go
/ Copyright 2021 The Go Authors. All rights reserved.
/ Use of this source code is governed by a BSD-style
/ license that can be found in the LICENSE file.
/ Package generics contains the new syntax supporting generic programming in
/ Go.
package generics
/ Variables with an instantiated type should be shown.
var X Type[int]
/ Parameterized types should be shown.
type Type[P any] struct {
Field P
}
/ Constructors for parameterized types should be shown.
func Constructor[lowerCase any]() Type[lowerCase] {
return Type[lowerCase]{}
}
/ MethodA uses a different name for its receiver type parameter.
func (t Type[A]) MethodA(p A) {}
/ MethodB has a blank receiver type parameter.
func (t Type[_]) MethodB() {}
/ MethodC has a lower-case receiver type parameter.
func (t Type[c]) MethodC() {}
/ Constraint is a constraint interface with two type parameters.
type Constraint[P, Q interface{ string | ~int | Type[int] }] interface {
~int | ~byte | Type[string]
M() P
}
/ int16 shadows the predeclared type int16.
type int16 int
/ NewEmbeddings demonstrates how we filter the new embedded elements.
type NewEmbeddings interface {
string / should not be filtered
int16
struct{ f int }
~struct{ f int }
*struct{ f int }
struct{ f int } | ~struct{ f int }
}
/ Func has an instantiated constraint.
func Func[T Constraint[string, Type[int]]]() {}
/ AnotherFunc has an implicit constraint interface.
/
/ Neither type parameters nor regular parameters should be filtered.
func AnotherFunc[T ~struct{ f int }](_ struct{ f int }) {}
/ AFuncType demonstrates filtering of parameters and type parameters. Here we
/ don't filter type parameters (to be consistent with function declarations),
/ but DO filter the RHS.
type AFuncType[T ~struct{ f int }] func(_ struct{ f int })
/ See issue #49477: type parameters should not be interpreted as named types
/ for the purpose of determining whether a function is a factory function.
/ Slice is not a factory function.
func Slice[T any]() []T {
return nil
}
/ Single is not a factory function.
func Single[T any]() *T {
return nil
}