使用反射，如何动态创建结构“类型”？

Consider the following struct :

type Foo struct{}

func (f *Foo) foo() {
    fmt.Println("Hello")
}

Using reflect I would like to generate a custom struct type that overrides a set of methods. When doing the work manually what I want to do is :

type Edit struct{
    Foo
}

func (e *Edit) foo() {
    e.Foo.foo()
    fmt.Println("World")
}

But instead of writing this manually, I would like to make a function that does such override automatically for any given struct.

I know that I can instantiate a struct using :

res := reflect.New(reflect.TypeOf(origin))

but in this situation, we can't edit methods.

So how with reflect can I create a struct type that wraps an existing type like explained above?

You can achieve something extremely similar to what you are asking for using Method Values. You could do something like the following:

package main

import (
    "fmt"
)

type Foo struct {
    sayHelloAgain func()
}

func (f *Foo) SayHello() { 
    fmt.Print("Hello,")
    f.sayHelloAgain() 
}

func main() {
    edit := struct{Foo}{}
    edit.sayHelloAgain = func(){ fmt.Println(" World!") }
    edit.SayHello()

}

Go Playground

As you can see, you can create an anonymous struct which will be able to call the SayHello function, which then calls the receiver's dynamically set sayHelloAgain method.

I think this will be the closest you will get to your goal, and works as you requested (without relection)