DSL to declare the arguments for an action.
See notes_actions.txt, "private" for the Tcl command using this.

description TEXT

	Help text for the private, i.e. command.
	Has no other place for it than its argument specification.

use NAME
	Take the named value from the associative data store, possibly
	following the chain of command. Treat it as script of DSL
	commands and run them in place.

input	NAME DESCRIPTION ?PARAMETER_SPEC?
splat	NAME DESCRIPTION ?PARAMETER_SPEC?
option	NAME DESCRIPTION ?PARAMETER_SPEC?
state	NAME DESCRIPTION ?PARAMETER_SPEC?

	Declare a parameter, argument or option.
	Name and description are mandatory.
	All other attributes are effected through the specification.

=============================
value API

options - query which flags are defined by the argument or flag.
reset   - reset value to empty

process NAME QUEUE - Parse head of queue to get user value of argument or flag.

get - 
