Added an example of how to use the flow

examples/flow/main.go

@@ -0,0 +1,104 @@
+package main
+
+import "git.tebibyte.media/sashakoshka/tomo"
+import "git.tebibyte.media/sashakoshka/tomo/flow"
+import "git.tebibyte.media/sashakoshka/tomo/elements/basic"
+import "git.tebibyte.media/sashakoshka/tomo/elements/layouts"
+import _ "git.tebibyte.media/sashakoshka/tomo/backends/x"
+
+func main () {
+	tomo.Run(run)
+}
+
+func run () {
+	window, _ := tomo.NewWindow(2, 2)
+	window.SetTitle("adventure")
+	container := basic.NewContainer(layouts.Vertical { true, true })
+	window.Adopt(container)
+
+	var world flow.Flow
+	world.Transition = container.DisownAll
+	world.Stages = map [string] func () {
+		"start": func () {
+			label := basic.NewLabel (
+				"you are standing next to a river.", false)
+			container.Adopt(label, true)
+			
+			button0 := basic.NewButton("go in the river")
+			button0.OnClick(world.SwitchFunc("wet"))
+			container.Adopt(button0, false)
+			button0.Select()
+			
+			button1 := basic.NewButton("walk along the river")
+			button1.OnClick(world.SwitchFunc("house"))
+			container.Adopt(button1, false)
+			
+			button2 := basic.NewButton("turn around")
+			button2.OnClick(world.SwitchFunc("bear"))
+			container.Adopt(button2, false)
+		},
+		"wet": func () {
+			label := basic.NewLabel (
+				"you get completely soaked.\n" +
+				"you die of hypothermia.", false)
+			container.Adopt(label, true)
+			
+			button0 := basic.NewButton("try again")
+			button0.OnClick(world.SwitchFunc("start"))
+			container.Adopt(button0, false)
+			button0.Select()
+			
+			button1 := basic.NewButton("exit")
+			button1.OnClick(tomo.Stop)
+			container.Adopt(button1, false)
+		},
+		"house": func () {
+			label := basic.NewLabel (
+				"you are standing in front of a delapidated " +
+				"house.", false)
+			container.Adopt(label, true)
+			
+			button1 := basic.NewButton("go inside")
+			button1.OnClick(world.SwitchFunc("inside"))
+			container.Adopt(button1, false)
+			button1.Select()
+			
+			button0 := basic.NewButton("turn back")
+			button0.OnClick(world.SwitchFunc("start"))
+			container.Adopt(button0, false)
+		},
+		"inside": func () {
+			label := basic.NewLabel (
+				"you are standing inside of the house.\n" +
+				"it is dark, but rays of light stream " +
+				"through the window.\n" +
+				"there is nothing particularly interesting " +
+				"here.", false)
+			container.Adopt(label, true)
+			
+			button0 := basic.NewButton("go back outside")
+			button0.OnClick(world.SwitchFunc("house"))
+			container.Adopt(button0, false)
+			button0.Select()
+		},
+		"bear": func () {
+			label := basic.NewLabel (
+				"you come face to face with a bear.\n" +
+				"it eats you (it was hungry).", false)
+			container.Adopt(label, true)
+			
+			button0 := basic.NewButton("try again")
+			button0.OnClick(world.SwitchFunc("start"))
+			container.Adopt(button0, false)
+			button0.Select()
+			
+			button1 := basic.NewButton("exit")
+			button1.OnClick(tomo.Stop)
+			container.Adopt(button1, false)
+		},
+	}
+	world.Switch("start")
+
+	window.OnClose(tomo.Stop)
+	window.Show()
+}

flow/flow.go

@@ -25,6 +25,14 @@ func (flow Flow) Switch (stage string) {
 	stageCallback()
 }
 
+// SwitchFunc returns a function that calles Switch with the specfied stage
+// name. This is useful for creating callbacks.
+func (flow Flow) SwitchFunc (stage string) (callback func ()) {
+	return func () {
+		flow.Switch(stage)
+	}
+}
+
 // Stage returns the name of the current stage the flow is on.
 func (flow Flow) Stage () (name string) {
 	return flow.stage