lightseekorg--tokenspeed/python/tokenspeed/runtime/utils/dispatch.py

# Copyright (c) 2026 LightSeek Foundation
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

from collections.abc import Callable
from typing import Any


class TypeBasedDispatcher:
    def __init__(self, mapping: list[tuple[type, Callable]]):
        self._mapping = mapping
        self._fallback_fn = None

    def add_fallback_fn(self, fallback_fn: Callable):
        self._fallback_fn = fallback_fn

    def __iadd__(self, other: "TypeBasedDispatcher"):
        self._mapping.extend(other._mapping)
        return self

    def __call__(self, obj: Any):
        for ty, fn in self._mapping:
            if isinstance(obj, ty):
                return fn(obj)

        if self._fallback_fn is not None:
            return self._fallback_fn(obj)
        raise ValueError(f"Invalid object: {obj}")