Re: A Rust Contributor Tries Their Hand at Go

drawing.go

package main

import "os"

var (
	Red  = rgb(255, 0, 0)
	Blue = rgb(0, 0, 255)
)

func rgb(red, green, blue int) Color {
	return Color(red<<16 + green<<8 + blue)
}

type Color int

type Point struct {
	x int
	y int
}

type Graphics interface {
	// add your graphics thingies here
}

type Action func(Graphics)

func Quit(g Graphics) {
	os.Exit(0)
}

func DrawLine(color Color, a Point, b Point) Action {
	return func(g Graphics) {
		// draw a line with the graphics context
	}
}

func DrawTriangle(color Color, fill Color, a Point, b Point) Action {
	return func(g Graphics) {
		// draw a triangle with the graphics context
	}
}

func SetBackground(color Color) Action {
	return func(g Graphics) {
		// set the background
	}
}

func paintingLoop(ch chan Action) {
	// create your graphics context here
	var g Graphics = nil

	// shorthand for a loop over receiving over
	// a channel
	for action := range ch {
		action(g)
	}
}

func drawThingy(ch chan Action) {
	ch <- DrawLine(Red, Point{x: 0, y: 0}, Point{x: 1, y: 1})
	ch <- SetBackground(Blue)

	// Not possible
	// ch <- true
	// ch <- "foobar"
}

func main() {
	// do some setup
	ch := make(chan Action, 100)

	// Creates a goroutine which will handle the
	// event loop
	go func() {
		// create the window, etc
		paintingLoop(ch)
	}()

	// ch can be handed out to various
	// consumers now
	drawThingy(ch)
}

Here's a rework of the original go program in (hopefully) a more idiomatic go style.