Go by Example: Inheritence (interface)

package main

import (
    "fmt"
)

type PointType int

const (
    PointT PointType = iota
    Point3DT
)

type IPoint interface {
    X() float64
    Y() float64
    SetX(float64)
    SetY(float64)
    GetX() float64
    GetY() float64
}

embed IPoint in IPoint3D will inherit all method of IPoint

 
type IPoint3D interface {
    IPoint
    Z() float64
    SetZ(float64)
}

type Point struct {
    x float64
    y float64
}

Point struct is embedded

 
type Point3D struct {

    Point
    z float64
}

factory pattern for multiple struct

 
func NewPoint(t PointType, args ...float64) IPoint {
    switch t {
    case Point3DT:
        return &Point3D{Point: Point{x: args[0], y: args[1]}, z: args[2]}
    default:

        return &Point{x: args[0], y: args[1]}
    }
}

func (p *Point) X() float64 {
    return p.x
}

func (p *Point) Y() float64 {
    return p.y
}

func (p *Point) SetX(x float64) {
    p.x = x
}

func (p *Point) SetY(y float64) {
    p.y = y
}

func (p *Point) GetX() float64 {
    return p.x
}

func (p *Point) GetY() float64 {
    return p.y
}

func (p *Point3D) Z() float64 {
    return p.z
}

func (p *Point3D) SetZ(z float64) {
    p.z = z
}

func main() {

this implements polymorphism of slice

 
    points := make([]IPoint, 0)

    p1 := NewPoint(PointT, 3, 4)
    p2 := NewPoint(Point3DT, 1, 2, 3)

    points = append(points, p1, p2)

    for _, p := range points {
        fmt.Printf("(%.2f %.2f)\n", p.GetX(), p.GetY())
    }
}

go run examples/inheritence-interface.go
 
(3.00 4.00)
(1.00 2.00)

Next example: Generics.

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