define verb PROLOG
	image SYS$PROLOG:PROLOG
	parameter
		P1,
		label = SOURCE,
		value
			(type = $file)
	qualifier
		COMPILE,
		label = COMPILE,
		nonnegatable,
		placement = global,
	qualifier
		INIT,
		label = INIT,
		negatable,
		placement = global,
		value
			(default = "SYS$PROLOG:INITIAL.PRO",
			 type = $file)
	qualifier
		INPUT,
		label = INPUT,
		nonnegatable,
		placement = global,
		default,
		value
			(required,
			 type = $file)
	qualifier
		LIBRARY,
		label = LIBRARY,
		nonnegatable,
		placement = global,
		value
			(required)
	qualifier
		LINK,
		label = LINK,
		nonnegatable,
		placement = global,
	qualifier
		LOAD,
		label = LOAD,
		negatable,
		placement = global,
		default,
		value
			(default = "SYS$PROLOG:INITIAL.PKB",
			 type = $file)
	qualifier
		LOG,
		label = LOGFILE,
		negatable,
		placement = global,
		value
			(default = "PROLOG.LOG",
			 type = $file)
	qualifier
		OUTPUT,
		label = OUTPUT,
		nonnegatable,
		placement = global,
		default,
		value
			(required,
			 type = $file)
	qualifier
		SAVE,
		label = SAVE,
		nonnegatable,
		placement = global,
		default,
		value
			(required,
			 type = $file)
	qualifier
		WARNINGS,
		label = WARNINGS,
		negatable,
		placement = global
	disallow
		INIT and LOAD
	disallow
		(neg INIT) and (neg LOAD)
	disallow
		COMPILE and (LOAD or INIT)
	disallow
		LINK and (LOAD or INIT)
	disallow
		LINK and SOURCE
	disallow
		LINK and COMPILE