Support nested subcommands or groups of commands or

[szaghi]

Support arbitrarily nesting command line utilities: many CLI tools (e.g. git) has mode or group of commands, e.g. git commit [commit-options], git tag [tag-options] ...

Python module argparse has subparsers (used in FoBiS.py for example).

Python module click (see) has group of commands.

FLAP should implement on of these (or similar) paradigms.

[szaghi]

After writing to Victor, the plan for this feature design is:

• touch the CLI public signature (that is the only one public thing) as less as possible, ideally I want to push a fully backward compatible release; in other words, I want to add the new feature without broken the present usage API; this means that Type_Command_Line_Interface is now being changed, but only it internal, private definition: the public methods signature (init, get, add, parse...) should be untouched;
• to achieve the previous goal and in the meanwhile support the new feature, I am going to introduce a new private type, Type_Command_Line_Arguments_Group, that is just a grouped collections of Type_Command_Line_Argument (that should remain untouched also internally) with some "facilities" to handle the group itself;
• modify the internal definition of Type_Command_Line_Interface in order that is behaves as following:
  • if the user defines a "standard" CLI without nested/grouped CLAs or the CLAs under defining is not associated to a specific group, these CLAs are stored into a default group that is automatically created always; the user interaction remains as it is now;
  • if the user defines that the CLAs under defining must be associated to a particular group, the default group is changed (on the fly) to an array of groups (indeed it is always an array: only its dimension changes): the group number 0 is always devoted to CLAs that are not grouped, while other groups (>=1) are the other grouped CLAs.

Questions to be answered:

• how different CLAs-groups must interact?
• how mixed grouped CLAs/non grouped CLAs should interact?