User_Interface

		procedure Try_Help;
	Print an error message, telling the user to try --help.

		procedure Invalid_Option
	The option with the given argument is invalid.
	Param  Type  Description in Index  Positive  Print the argument at this index.

		procedure Too_Few_Arguments;
	There are not enough command line options.

		procedure Too_Many_Arguments;
	There are too many command line options.

		procedure Start
	Handling for common options like -v and -h.
	Param  Type  Description in Program_Name  String  Name of executable. in Parameters  String  List of parameters. in Description  String  What does the program do? in Parameters_Text  String  Text for parameters. in Extra_Options  String  Options beyond -h, -v, -q. out Index  Positive  First unhandled parameter. out Exit_Now  Boolean  Exit program instantly.