go interfaces / published by https://github.com/dacr/code-examples-manager #86809bee-7d41-4bca-ac58-78ac3ef26952/5a003f867e21af6ce00a9cc04eb76b4d9ddded0b

interfaces.go

/*?sr/bin/true; exec /usr/bin/env nix-shell -p go --run "go run $0" #*/
// summary : go interfaces
// keywords : go, interfaces, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 86809bee-7d41-4bca-ac58-78ac3ef26952
// created-on : 2025-03-27T13:30:23+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : nix-shell -p go --run "go run $file"
package main

type Color string

// -----------------------------------------------------------------------------------------

type Organism interface {
	Name() string
}

type Colored interface {
	Color() Color
}
type Creature interface {
	Organism
	Colored
}

// -----------------------------------------------------------------------------------------

type Fish struct {
	name   string
	color  Color
	weight int16
}

type Bird struct {
	name   string
	color  Color
	weight int16
}

// No need to use an implicit or extends keywords !

// -----------------------------------------------------------------------------------------

func (f Fish) Name() string {
	return f.name
}

func (f Fish) Color() Color {
	return f.color
}

func (b Bird) Name() string {
	return b.name
}

func (b Bird) Color() Color {
	return b.color
}

// -----------------------------------------------------------------------------------------

func main() {
	fish := Fish{"Goldfish", "Blue", 10}
	bird := Bird{"Parrot", "Green", 10}

	creatures := []Creature{fish, bird}
	organisms := creatures

	for _, creature := range creatures {
		println(creature.Name())
	}

	for _, organism := range organisms {
		println(organism.Name())
	}
}