define syntax help_syntax
	noparameters
	qualifier	help,		default
define verb dsf
	image		sys$disk:[]dsf.exe
	parameter	p1,		label=input,
					prompt="File",
					value(required,type=$FILE)
	parameter	p2,		label=key,
					prompt="Key"
	qualifier	help,		nonnegatable
					syntax=help_syntax
	qualifier	output,		nonnegatable,
					value(required,type=$FILE)
	qualifier	forwards,	nonnegatable
	qualifier	backwards,	nonnegatable,
					default
	qualifier	high_security,	negatable,
					default
	qualifier	block,		negatable
	qualifier	log,		negatable,
					default
	disallow	any2(help,output)
	disallow	any2(help,high_security)
	disallow	any2(help,block)
	disallow	any2(help,log)
	disallow	any2(help,forwards,backwards)