aboutsummaryrefslogtreecommitdiffstats
path: root/library/python/func/__init__.py
blob: 12a280bddc0f9a8544ab50172a70d24435b2bb32 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
import functools
import threading
import collections


def map0(func, value):
    return func(value) if value is not None else value


def single(x):
    if len(x) != 1:
        raise Exception('Length of {} is not equal to 1'.format(x))
    return x[0]


class _Result(object):
    pass


def lazy(func):
    result = _Result()

    lock = threading.Lock()

    @functools.wraps(func)
    def wrapper(*args):
        try:
            return result.result
        except AttributeError:
            with lock:
                try:
                    return result.result
                except AttributeError:
                    result.result = func(*args)

            return result.result

    return wrapper


def lazy_property(fn):
    attr_name = '_lazy_' + fn.__name__

    lock = threading.Lock()

    @property
    def _lazy_property(self):
        if hasattr(self, attr_name):
            return getattr(self, attr_name)

        with lock:
            if not hasattr(self, attr_name):
                setattr(self, attr_name, fn(self))
            return getattr(self, attr_name)

    return _lazy_property


class classproperty(object):
    def __init__(self, func):
        self.func = func

    def __get__(self, _, owner):
        return self.func(owner)


class lazy_classproperty(object):
    def __init__(self, func):
        self.func = func

    def __get__(self, _, owner):
        attr_name = '_lazy_' + self.func.__name__

        if not hasattr(owner, attr_name):
            setattr(owner, attr_name, self.func(owner))
        return getattr(owner, attr_name)


def memoize(limit=0, thread_local=False):
    assert limit >= 0

    def decorator(func):
        memory = {}
        lock = threading.Lock()

        if limit:
            keys = collections.deque()

            def get(args):
                try:
                    return memory[args]
                except KeyError:
                    with lock:
                        if args not in memory:
                            fargs = args[-1]
                            memory[args] = func(*fargs)
                            keys.append(args)
                            if len(keys) > limit:
                                del memory[keys.popleft()]
                        return memory[args]

        else:

            def get(args):
                if args not in memory:
                    with lock:
                        if args not in memory:
                            fargs = args[-1]
                            memory[args] = func(*fargs)
                return memory[args]

        if thread_local:

            @functools.wraps(func)
            def wrapper(*args):
                th = threading.current_thread()
                return get((th.ident, th.name, args))

        else:

            @functools.wraps(func)
            def wrapper(*args):
                return get(('', '', args))

        return wrapper

    return decorator


# XXX: add test
def compose(*functions):
    def compose2(f, g):
        return lambda x: f(g(x))

    return functools.reduce(compose2, functions, lambda x: x)


class Singleton(type):
    _instances = {}

    def __call__(cls, *args, **kwargs):
        if cls not in cls._instances:
            cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls]


def stable_uniq(it):
    seen = set()
    res = []
    for e in it:
        if e not in seen:
            res.append(e)
            seen.add(e)
    return res


def first(it):
    for d in it:
        if d:
            return d


def split(data, func):
    l, r = [], []
    for e in data:
        if func(e):
            l.append(e)
        else:
            r.append(e)
    return l, r


def flatten_dict(dd, separator='.', prefix=''):
    return (
        {
            prefix + separator + k if prefix else k: v
            for kk, vv in dd.items()
            for k, v in flatten_dict(vv, separator, kk).items()
        }
        if isinstance(dd, dict)
        else {prefix: dd}
    )