LSD Specification for a Digital Watch

(As discussed in EM for Concurrency Lecture 6)

agent power() {
    derivate
	power_s = battery_charge(time)	// three-valued 2,1,0
}

agent watch() {
    derivate
	LIVE = (power_s >= 1)
    oracle
	power_s
    agent
	main() {	// as specified below
	.....
    }
    agent light() {
    }
    agent alarm_st() {
	derivate
		LIVE=LIVEmain
	oracle
		LIVEmain , displays_s, alarm_s
	state
		alarm_s = D, set_time = 00.00
	handle
		alarm_s	// 1:Disab, 2:Enab
	protocol
		displays_s == A & alarm_st == D & !d -> alarm_st = E
		displays_s == A & alarm_st == E & !d -> alarm_st = D
    }		// !d here means that button d has been pressed
    agent chime_st() {
    }
    agent clock() {
    }
    agent stopwatch() {
    }
	.......
}

agent main() {
    derivate
	LIVE=LIVEwatch
    oracle
	LIVEwatch, main_s, alarm_s
    state
	main_s = D	// an integer 1:Displays, 2:Beep||displays
    handle
	main_s
    protocol
	(main_s==D) & (time==set_time) & alarm_s==E -> main_s=B
    agent displays() {
	derivate
		LIVE=LIVEmain
	oracle
		LIVEmain
	state
		displays_s = T	// 1:Time, 2:Update, 3:Date, etc
	handle
		displays_s, update_s, upalarm_s
	protocol
		displays_s==T & !c -> update_s=1,
		displays_s==T & !d -> displays_s=D,
		displays_s==A & !c -> upalarm_s=1,
		.....
		displays_s!=S & displays_s!=T &2-min -> displays_s=T
	agent disp_date() {
	    derivate
		LIVE = LIVEdisplays & displays_s==D,
		"watch_display = date as of clock()"
	    oracle
		LIVEdisplays, displays_s
	}
	agent disp_time() { ......
	}
	agent disp_upalarm() {
	    derivate
		LIVE = LIVEdisplays & upalarm_s>0,
		displays_s = (upalarm_s==0%4)?A:UA
		"watch_display = time as of alarm setting with right digit highlighted"
	    oracle
		LIVEdisplays, upalarm_s
	    state
		upalarm_s = M	// 1:Min, 2:TenMin, 3:Hr, 4=0(mod 4): Alarm
	    handle
		upalarm_s, set_time
	    protocol
		!b or 2-min -> upalarm_s=A,
		!c -> upalarm++,
		"event -> update set_time so as to increment highlighted digit in set_time"
	}
	..................
    }
    agent beep() {
	derivate
	    LIVE=LIVEmain & main_s==B
	state
	    main_s
	protocol
	    beep_stop -> main_s
    }
}	// end main()