Evaluation: {{.Title}}
Constants and functions: {{printf "%g: %#3X" 1.2+2i 123}}
Control structures {{range $s.Text}} {{.}} {{end}}

// One iteration:
switch state {
case state1: 
	state = action1()
case state2:
	state = action2()
case state3: 
	state = action3()
}

// run lexes the input by executing state functions
// until the state is nil.
func run() {
	for state := startState; state != nil; {
		state = state(lexer)
	}
}