1.4 KiB
1.4 KiB
| title |
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| Go Methods |
Go Methods
Golang types can have methods. A method is a function with a special argument, the receiver.
type Rectangle struct {
height, width int64
}
func (r Receiver) getArea() int64 {
return r.height * r.height
}
r := Rectangle{10, 20}
r.getArea() // 200
Here, type Rectangle has got a method called getArea that returns the area of the rectangle.
The receiver here is r.
This code is equivalent to:
type Rectangle struct {
height, width int64
}
func getArea(r Receiver) int 64{
return r.height * r.height
}
r := Rectangle{10, 20}
getArea(r) // 200
Now the getArea method receives r as an argument, instead of a receiver. The functionality is equivalent.
Pointer receiver
You can pass a pointer as a receiver:
type MyInt int64
func (m *MyInt) setToZero() {
*m = MyInt(0)
}
m := MyInt(10)
m.setToZero() // m == 0
Extension methods
If you want to create a method on a type defined in other package, e.g. int you can use a simple wrapper like this:
type MyInt int64
func (m MyInt) add10() int64 {
return m + 10
}
m := MyInt(10)
m.add10() // 20