Golang Embedding

• Description
• Interfaces
• Structs

Description

[[https://golang.org/doc/effective\_go.html#embedding]\[Embedding]] is Gos answer to subclasses. There’s one caveat:

#+BEGIN_QUOTE
There’s an important way in which embedding differs from subclassing. When we embed a type, the methods of that type become methods of the outer type, but when they are invoked the receiver of the method is the inner type, not the outer one.
#+END_QUOTE

Interfaces

type Reader interface {
    Read(p []byte) (n int, err error)
}
 
type Writer interface {
    Write(p []byte) (n int, err error)
}
 
type ReadWriter interface {
    Reader
    Writer
}

~ReadWriter~ “extends” Reader & Writer in the example above.

Structs

type ReadWriter struct {
    ,*Reader  // *bufio.Reader
    ,*Writer  // *bufio.Writer
}
 
func (rw *ReadWriter) Read(p []byte) (n int, err error) {
    return rw.reader.Read(p)
}