argklass 1.4.4
Argparse generator from dataclass
License: BSD 3-Clause License

argklass
========

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Inspired by `Simple Parsing <https://github.com/lebrice/SimpleParsing>`_, simplified
and extended to build extensive, extendable command line interface without much code.


.. code-block:: bash

   pip install argklass


Features
--------

* Automatic cli discovery and command plugin

   .. code-block:: bash

      # Folder structure
      project/cli/
      ├── __init__.py         <= empty
      ├── editor/
      │   ├── __init__.py     <= ParentCommand(editor)
      │   ├── cook.py         <= Command(cook)
      │   ├── client.py       <= Command(client)
      │   ├── game.py         <= Command(game)
      │   └── open.py         <= Command(open)
      └── uat/
         ├── __init__.py     <= ParentCommand(uat)
         ├── localize.py     <= Command(localize)
         └── test.py         <= Command(test)

      #  editor/__init__.py
      from argklass.command import ParentCommand

      class Editor(ParentCommand):
         name = "editor"


      COMMANDS = Editor

      # cook.py
      from argklass.command import Command

      class Cook(Command):
         name = "cook"

         @staticmethod
         def execute(args) -> int:
            print("cook")

      COMMANDS = Cook

      #
      cli = CommandLineInterface(project.cli)
      cli.run()

      # or
      cli.run(["editor", "cook", "--help"])

      #
      cli editor cook --help
      cli uat localize --help


* New Argument format
   * able to show the entire command line interface with all its subparsers
   * new format mirror dataclass syntax

   .. code-block::

      editor                                           Set of commands to launch the editors in different modes
         server                                       Parameters added to the Map URL
         game                                         docstring ...
         client                                       docstring ...
         resavepackages                               docstring ...
         cook                                         docstring ...
         ml                                           Launch unreal engine with mladapter setup
         editor                                       Other arguments
         open                                         docstring ...
         localize                                     docstring ...
         worldpartition                               Convert a UE4 map using world partition
         -h, --help                                   Show help
      engine                                           Set of commands to manage engine installation/source
            add                                          docstring ...
            update                                       Update the engine source code
      format                                             docstring ...
            --profile: str                               docstring ...
            --file: str                                  docstring ...
            --fail_on_error: bool = False                docstring ...
            --col: int = 24                              docstring ...

* Compact argparse definition

   .. code-block:: python

      def workdir():
         d = os.getcwd()
         if os.access(d, os.W_OK):
            return d
         return None


      @dataclass
      class MyArguments:
         a  : str                                                    # Positional
         b  : int                = 20                                # My argument
         c  : bool               = False                             # My argument
         d  : int                = choice(0, 1, 2, 3, 4, default=1)  # choices
         e  : List[int]          = argument(default=[0])             # list
         f  : Optional[int]      = None                              # Optional
         p  : Tuple[int, int]    = (1, 1)                            # help p
         g  : Color              = Color.RED                         # help g
         s  : SubArgs            = SubArgs                           # helps group
         cmd: Union[cmd1, cmd2]  = subparsers(cmd1=cmd1, cmd2=cmd2)  # Command subparser
         de : str                = deduceable(workdir)

      parser = ArgumentParser()
      parser.add_arguments(MyArguments)
      args = parser.parse_args()

* Save and load arguments from configuration files

   .. code-block:: python

      parser = build_parser(commands)

      # load/save defaults before parsing
      save_defaults(parser, "config.hjson")
      apply_defaults(parser, "config.hjson")

      args = parser.parse_args(["editor", "editor"])

      # load save arguments after parsing
      save_as_config(parser, args, "dump.hjson")
      apply_config(parser, args, "dump.hjson")

* Lower level interface, that gives you back all of argparse power

   .. code-block:: python

      @dataclass
      class SubArgs:
         aa: str = argument(default="123")


      @dataclass
      class cmd1:
         args: str = "str1"


      @dataclass
      class cmd2:
         args: str = "str2"


      @dataclass
      class MyArguments:
         a: str                  = argument(help="Positional")
         b: int                  = argument(default=20, help="My argument")
         c: bool                 = argument(action="store_true", help="My argument")
         d: int                  = argument(default=1, choices=[0, 1, 2, 3, 4], help="choices")
         e: List[int]            = argument(default=[0], help="list")
         f: Optional[int]        = argument(default=None, help="Optional")
         p: Tuple[int, int]      = argument(default=(1, 1), help="help p")
         g: Color                = argument(default=Color.RED, help="help g")
         s: SubArgs              = group(default=SubArgs, help="helps group")
         cmd: Union[cmd1, cmd2]  = subparsers(cmd1=cmd1, cmd2=cmd2)


      parser = ArgumentParser()
      parser.add_arguments(MyArguments)
      args = parser.parse_args()


Architecture
------------

argklass works by building the argument parser as a tree, adding
metadata to each nodes when necessary.

One of the core component is ``ArgumentParserIterator`` which traverse the parsing tree.
Each features, such as argument grouping into dataclasses or saving/loading configuration,
are implemented as a simple traversal.

This enable us to implement each feature independently from each other and make them optional.