Class decorator to register statements

01cds_decorator_ren.py

import renpy # type: ignore
"""renpy
python early:
"""
import inspect

__register_params = frozenset(inspect.signature(renpy.register_statement).parameters) - {"name", "parse", "execute"}
global register_decorator
def register_decorator(cls):
    """A class decorator which registers a new Creator-defined statement.

    The "parse" parameter of renpy.register_statement should be either the
    class constructor itself or a method named "parse" (likely a classmethod
    or a staticmethod) returning an instance of the class. The name of the
    statement will be the class name unless a "name" class attribute is
    present, which should be a string. Instead of the "execute" parameter,
    Ren'Py will look for a method named "execute", or in its absence, the
    class's `__call__` method to call the object like a function.

    All other parameters to the register_statement function can be set as
    class attributes named the same way.
    """
    name = getattr(cls, "name", cls.__name__)
    parse = getattr(cls, "parse", cls)
    execute = getattr(cls, "execute", None) or cls.__call__
    renpy.register_statement(
        name,
        parse=parse,
        execute=execute,
        **{k:getattr(cls, k) for k in __register_params.intersection(vars(cls))}
    )
    return cls