def argument(short_name, long_name, description, default_value, validate = nil, &block)
			return define_value(short_name, long_name, description, false, default_value, validate || block)
		end
def argument(short_name, long_name, description, default_value, validate = nil, &block)
			return define_value(short_name, long_name, description, false, default_value, validate || block)
		end
This defines a command line argument that takes a value.