argklass 1.4.4

Argparse generator from dataclass

Inspired by Simple Parsing, simplified and extended to build extensive, extendable command line interface without much code.

pip install argklass

Features

• Automatic cli discovery and command plugin

  # 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

  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

  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

  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

  @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.