regex match case

regexmatch.py

import re


class R:
    def __init__(self, value):
        self._value = value


class MatchRegex(type):
    def __instancecheck__(cls, obj):
        if not isinstance(obj, R):
            raise TypeError("R expected")
        regex: re.Pattern = cls._regex
        if match := regex.fullmatch(obj._value):
            for name, value in match.groupdict().items():
                setattr(obj, name, value)
        return True


def matcher(regex):
    class Tmp(metaclass=MatchRegex):
        _regex = re.compile(regex)

    return Tmp


R1 = matcher(r"(?P<a>\w+) - (?P<b>\w+)")
R2 = matcher(r"(?P<a>\w+)")

match R("1 - 2"):
    case R1(a=a, b=b):
        print("matched r1", a, b)
    case R2(a=a):
        print("matched r2", a)
    case _:
        print("no match")