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1# Copyright 2024 The Bazel Authors. All rights reserved.
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15"""Enum-like object utilities
16
17This is a separate file to minimize transitive loads.
18"""
19
20def enum(methods = {}, **kwargs):
21    """Creates a struct whose primary purpose is to be like an enum.
22
23    Args:
24        methods: {type}`dict[str, callable]` functions that will be
25            added to the created enum object, but will have the enum object
26            itself passed as the first positional arg when calling them.
27        **kwargs: The fields of the returned struct. All uppercase names will
28            be treated as enum values and added to `__members__`.
29
30    Returns:
31        `struct` with the given values. It also has the field `__members__`,
32        which is a dict of the enum names and values.
33    """
34    members = {
35        key: value
36        for key, value in kwargs.items()
37        if key.upper() == key
38    }
39
40    for name, unbound_method in methods.items():
41        # buildifier: disable=uninitialized
42        kwargs[name] = lambda *a, **k: unbound_method(self, *a, **k)
43
44    self = struct(__members__ = members, **kwargs)
45    return self
46