mirror of
https://github.com/Lucas-V-L/lucasvl.nl.git
synced 2024-10-29 19:38:16 -05:00
526 lines
13 KiB
Python
526 lines
13 KiB
Python
import functools
|
|
import time
|
|
import inspect
|
|
import collections
|
|
import types
|
|
import itertools
|
|
|
|
import setuptools.extern.more_itertools
|
|
|
|
from typing import Callable, TypeVar
|
|
|
|
|
|
CallableT = TypeVar("CallableT", bound=Callable[..., object])
|
|
|
|
|
|
def compose(*funcs):
|
|
"""
|
|
Compose any number of unary functions into a single unary function.
|
|
|
|
>>> import textwrap
|
|
>>> expected = str.strip(textwrap.dedent(compose.__doc__))
|
|
>>> strip_and_dedent = compose(str.strip, textwrap.dedent)
|
|
>>> strip_and_dedent(compose.__doc__) == expected
|
|
True
|
|
|
|
Compose also allows the innermost function to take arbitrary arguments.
|
|
|
|
>>> round_three = lambda x: round(x, ndigits=3)
|
|
>>> f = compose(round_three, int.__truediv__)
|
|
>>> [f(3*x, x+1) for x in range(1,10)]
|
|
[1.5, 2.0, 2.25, 2.4, 2.5, 2.571, 2.625, 2.667, 2.7]
|
|
"""
|
|
|
|
def compose_two(f1, f2):
|
|
return lambda *args, **kwargs: f1(f2(*args, **kwargs))
|
|
|
|
return functools.reduce(compose_two, funcs)
|
|
|
|
|
|
def method_caller(method_name, *args, **kwargs):
|
|
"""
|
|
Return a function that will call a named method on the
|
|
target object with optional positional and keyword
|
|
arguments.
|
|
|
|
>>> lower = method_caller('lower')
|
|
>>> lower('MyString')
|
|
'mystring'
|
|
"""
|
|
|
|
def call_method(target):
|
|
func = getattr(target, method_name)
|
|
return func(*args, **kwargs)
|
|
|
|
return call_method
|
|
|
|
|
|
def once(func):
|
|
"""
|
|
Decorate func so it's only ever called the first time.
|
|
|
|
This decorator can ensure that an expensive or non-idempotent function
|
|
will not be expensive on subsequent calls and is idempotent.
|
|
|
|
>>> add_three = once(lambda a: a+3)
|
|
>>> add_three(3)
|
|
6
|
|
>>> add_three(9)
|
|
6
|
|
>>> add_three('12')
|
|
6
|
|
|
|
To reset the stored value, simply clear the property ``saved_result``.
|
|
|
|
>>> del add_three.saved_result
|
|
>>> add_three(9)
|
|
12
|
|
>>> add_three(8)
|
|
12
|
|
|
|
Or invoke 'reset()' on it.
|
|
|
|
>>> add_three.reset()
|
|
>>> add_three(-3)
|
|
0
|
|
>>> add_three(0)
|
|
0
|
|
"""
|
|
|
|
@functools.wraps(func)
|
|
def wrapper(*args, **kwargs):
|
|
if not hasattr(wrapper, 'saved_result'):
|
|
wrapper.saved_result = func(*args, **kwargs)
|
|
return wrapper.saved_result
|
|
|
|
wrapper.reset = lambda: vars(wrapper).__delitem__('saved_result')
|
|
return wrapper
|
|
|
|
|
|
def method_cache(
|
|
method: CallableT,
|
|
cache_wrapper: Callable[
|
|
[CallableT], CallableT
|
|
] = functools.lru_cache(), # type: ignore[assignment]
|
|
) -> CallableT:
|
|
"""
|
|
Wrap lru_cache to support storing the cache data in the object instances.
|
|
|
|
Abstracts the common paradigm where the method explicitly saves an
|
|
underscore-prefixed protected property on first call and returns that
|
|
subsequently.
|
|
|
|
>>> class MyClass:
|
|
... calls = 0
|
|
...
|
|
... @method_cache
|
|
... def method(self, value):
|
|
... self.calls += 1
|
|
... return value
|
|
|
|
>>> a = MyClass()
|
|
>>> a.method(3)
|
|
3
|
|
>>> for x in range(75):
|
|
... res = a.method(x)
|
|
>>> a.calls
|
|
75
|
|
|
|
Note that the apparent behavior will be exactly like that of lru_cache
|
|
except that the cache is stored on each instance, so values in one
|
|
instance will not flush values from another, and when an instance is
|
|
deleted, so are the cached values for that instance.
|
|
|
|
>>> b = MyClass()
|
|
>>> for x in range(35):
|
|
... res = b.method(x)
|
|
>>> b.calls
|
|
35
|
|
>>> a.method(0)
|
|
0
|
|
>>> a.calls
|
|
75
|
|
|
|
Note that if method had been decorated with ``functools.lru_cache()``,
|
|
a.calls would have been 76 (due to the cached value of 0 having been
|
|
flushed by the 'b' instance).
|
|
|
|
Clear the cache with ``.cache_clear()``
|
|
|
|
>>> a.method.cache_clear()
|
|
|
|
Same for a method that hasn't yet been called.
|
|
|
|
>>> c = MyClass()
|
|
>>> c.method.cache_clear()
|
|
|
|
Another cache wrapper may be supplied:
|
|
|
|
>>> cache = functools.lru_cache(maxsize=2)
|
|
>>> MyClass.method2 = method_cache(lambda self: 3, cache_wrapper=cache)
|
|
>>> a = MyClass()
|
|
>>> a.method2()
|
|
3
|
|
|
|
Caution - do not subsequently wrap the method with another decorator, such
|
|
as ``@property``, which changes the semantics of the function.
|
|
|
|
See also
|
|
http://code.activestate.com/recipes/577452-a-memoize-decorator-for-instance-methods/
|
|
for another implementation and additional justification.
|
|
"""
|
|
|
|
def wrapper(self: object, *args: object, **kwargs: object) -> object:
|
|
# it's the first call, replace the method with a cached, bound method
|
|
bound_method: CallableT = types.MethodType( # type: ignore[assignment]
|
|
method, self
|
|
)
|
|
cached_method = cache_wrapper(bound_method)
|
|
setattr(self, method.__name__, cached_method)
|
|
return cached_method(*args, **kwargs)
|
|
|
|
# Support cache clear even before cache has been created.
|
|
wrapper.cache_clear = lambda: None # type: ignore[attr-defined]
|
|
|
|
return ( # type: ignore[return-value]
|
|
_special_method_cache(method, cache_wrapper) or wrapper
|
|
)
|
|
|
|
|
|
def _special_method_cache(method, cache_wrapper):
|
|
"""
|
|
Because Python treats special methods differently, it's not
|
|
possible to use instance attributes to implement the cached
|
|
methods.
|
|
|
|
Instead, install the wrapper method under a different name
|
|
and return a simple proxy to that wrapper.
|
|
|
|
https://github.com/jaraco/jaraco.functools/issues/5
|
|
"""
|
|
name = method.__name__
|
|
special_names = '__getattr__', '__getitem__'
|
|
if name not in special_names:
|
|
return
|
|
|
|
wrapper_name = '__cached' + name
|
|
|
|
def proxy(self, *args, **kwargs):
|
|
if wrapper_name not in vars(self):
|
|
bound = types.MethodType(method, self)
|
|
cache = cache_wrapper(bound)
|
|
setattr(self, wrapper_name, cache)
|
|
else:
|
|
cache = getattr(self, wrapper_name)
|
|
return cache(*args, **kwargs)
|
|
|
|
return proxy
|
|
|
|
|
|
def apply(transform):
|
|
"""
|
|
Decorate a function with a transform function that is
|
|
invoked on results returned from the decorated function.
|
|
|
|
>>> @apply(reversed)
|
|
... def get_numbers(start):
|
|
... "doc for get_numbers"
|
|
... return range(start, start+3)
|
|
>>> list(get_numbers(4))
|
|
[6, 5, 4]
|
|
>>> get_numbers.__doc__
|
|
'doc for get_numbers'
|
|
"""
|
|
|
|
def wrap(func):
|
|
return functools.wraps(func)(compose(transform, func))
|
|
|
|
return wrap
|
|
|
|
|
|
def result_invoke(action):
|
|
r"""
|
|
Decorate a function with an action function that is
|
|
invoked on the results returned from the decorated
|
|
function (for its side-effect), then return the original
|
|
result.
|
|
|
|
>>> @result_invoke(print)
|
|
... def add_two(a, b):
|
|
... return a + b
|
|
>>> x = add_two(2, 3)
|
|
5
|
|
>>> x
|
|
5
|
|
"""
|
|
|
|
def wrap(func):
|
|
@functools.wraps(func)
|
|
def wrapper(*args, **kwargs):
|
|
result = func(*args, **kwargs)
|
|
action(result)
|
|
return result
|
|
|
|
return wrapper
|
|
|
|
return wrap
|
|
|
|
|
|
def call_aside(f, *args, **kwargs):
|
|
"""
|
|
Call a function for its side effect after initialization.
|
|
|
|
>>> @call_aside
|
|
... def func(): print("called")
|
|
called
|
|
>>> func()
|
|
called
|
|
|
|
Use functools.partial to pass parameters to the initial call
|
|
|
|
>>> @functools.partial(call_aside, name='bingo')
|
|
... def func(name): print("called with", name)
|
|
called with bingo
|
|
"""
|
|
f(*args, **kwargs)
|
|
return f
|
|
|
|
|
|
class Throttler:
|
|
"""
|
|
Rate-limit a function (or other callable)
|
|
"""
|
|
|
|
def __init__(self, func, max_rate=float('Inf')):
|
|
if isinstance(func, Throttler):
|
|
func = func.func
|
|
self.func = func
|
|
self.max_rate = max_rate
|
|
self.reset()
|
|
|
|
def reset(self):
|
|
self.last_called = 0
|
|
|
|
def __call__(self, *args, **kwargs):
|
|
self._wait()
|
|
return self.func(*args, **kwargs)
|
|
|
|
def _wait(self):
|
|
"ensure at least 1/max_rate seconds from last call"
|
|
elapsed = time.time() - self.last_called
|
|
must_wait = 1 / self.max_rate - elapsed
|
|
time.sleep(max(0, must_wait))
|
|
self.last_called = time.time()
|
|
|
|
def __get__(self, obj, type=None):
|
|
return first_invoke(self._wait, functools.partial(self.func, obj))
|
|
|
|
|
|
def first_invoke(func1, func2):
|
|
"""
|
|
Return a function that when invoked will invoke func1 without
|
|
any parameters (for its side-effect) and then invoke func2
|
|
with whatever parameters were passed, returning its result.
|
|
"""
|
|
|
|
def wrapper(*args, **kwargs):
|
|
func1()
|
|
return func2(*args, **kwargs)
|
|
|
|
return wrapper
|
|
|
|
|
|
def retry_call(func, cleanup=lambda: None, retries=0, trap=()):
|
|
"""
|
|
Given a callable func, trap the indicated exceptions
|
|
for up to 'retries' times, invoking cleanup on the
|
|
exception. On the final attempt, allow any exceptions
|
|
to propagate.
|
|
"""
|
|
attempts = itertools.count() if retries == float('inf') else range(retries)
|
|
for attempt in attempts:
|
|
try:
|
|
return func()
|
|
except trap:
|
|
cleanup()
|
|
|
|
return func()
|
|
|
|
|
|
def retry(*r_args, **r_kwargs):
|
|
"""
|
|
Decorator wrapper for retry_call. Accepts arguments to retry_call
|
|
except func and then returns a decorator for the decorated function.
|
|
|
|
Ex:
|
|
|
|
>>> @retry(retries=3)
|
|
... def my_func(a, b):
|
|
... "this is my funk"
|
|
... print(a, b)
|
|
>>> my_func.__doc__
|
|
'this is my funk'
|
|
"""
|
|
|
|
def decorate(func):
|
|
@functools.wraps(func)
|
|
def wrapper(*f_args, **f_kwargs):
|
|
bound = functools.partial(func, *f_args, **f_kwargs)
|
|
return retry_call(bound, *r_args, **r_kwargs)
|
|
|
|
return wrapper
|
|
|
|
return decorate
|
|
|
|
|
|
def print_yielded(func):
|
|
"""
|
|
Convert a generator into a function that prints all yielded elements
|
|
|
|
>>> @print_yielded
|
|
... def x():
|
|
... yield 3; yield None
|
|
>>> x()
|
|
3
|
|
None
|
|
"""
|
|
print_all = functools.partial(map, print)
|
|
print_results = compose(more_itertools.consume, print_all, func)
|
|
return functools.wraps(func)(print_results)
|
|
|
|
|
|
def pass_none(func):
|
|
"""
|
|
Wrap func so it's not called if its first param is None
|
|
|
|
>>> print_text = pass_none(print)
|
|
>>> print_text('text')
|
|
text
|
|
>>> print_text(None)
|
|
"""
|
|
|
|
@functools.wraps(func)
|
|
def wrapper(param, *args, **kwargs):
|
|
if param is not None:
|
|
return func(param, *args, **kwargs)
|
|
|
|
return wrapper
|
|
|
|
|
|
def assign_params(func, namespace):
|
|
"""
|
|
Assign parameters from namespace where func solicits.
|
|
|
|
>>> def func(x, y=3):
|
|
... print(x, y)
|
|
>>> assigned = assign_params(func, dict(x=2, z=4))
|
|
>>> assigned()
|
|
2 3
|
|
|
|
The usual errors are raised if a function doesn't receive
|
|
its required parameters:
|
|
|
|
>>> assigned = assign_params(func, dict(y=3, z=4))
|
|
>>> assigned()
|
|
Traceback (most recent call last):
|
|
TypeError: func() ...argument...
|
|
|
|
It even works on methods:
|
|
|
|
>>> class Handler:
|
|
... def meth(self, arg):
|
|
... print(arg)
|
|
>>> assign_params(Handler().meth, dict(arg='crystal', foo='clear'))()
|
|
crystal
|
|
"""
|
|
sig = inspect.signature(func)
|
|
params = sig.parameters.keys()
|
|
call_ns = {k: namespace[k] for k in params if k in namespace}
|
|
return functools.partial(func, **call_ns)
|
|
|
|
|
|
def save_method_args(method):
|
|
"""
|
|
Wrap a method such that when it is called, the args and kwargs are
|
|
saved on the method.
|
|
|
|
>>> class MyClass:
|
|
... @save_method_args
|
|
... def method(self, a, b):
|
|
... print(a, b)
|
|
>>> my_ob = MyClass()
|
|
>>> my_ob.method(1, 2)
|
|
1 2
|
|
>>> my_ob._saved_method.args
|
|
(1, 2)
|
|
>>> my_ob._saved_method.kwargs
|
|
{}
|
|
>>> my_ob.method(a=3, b='foo')
|
|
3 foo
|
|
>>> my_ob._saved_method.args
|
|
()
|
|
>>> my_ob._saved_method.kwargs == dict(a=3, b='foo')
|
|
True
|
|
|
|
The arguments are stored on the instance, allowing for
|
|
different instance to save different args.
|
|
|
|
>>> your_ob = MyClass()
|
|
>>> your_ob.method({str('x'): 3}, b=[4])
|
|
{'x': 3} [4]
|
|
>>> your_ob._saved_method.args
|
|
({'x': 3},)
|
|
>>> my_ob._saved_method.args
|
|
()
|
|
"""
|
|
args_and_kwargs = collections.namedtuple('args_and_kwargs', 'args kwargs')
|
|
|
|
@functools.wraps(method)
|
|
def wrapper(self, *args, **kwargs):
|
|
attr_name = '_saved_' + method.__name__
|
|
attr = args_and_kwargs(args, kwargs)
|
|
setattr(self, attr_name, attr)
|
|
return method(self, *args, **kwargs)
|
|
|
|
return wrapper
|
|
|
|
|
|
def except_(*exceptions, replace=None, use=None):
|
|
"""
|
|
Replace the indicated exceptions, if raised, with the indicated
|
|
literal replacement or evaluated expression (if present).
|
|
|
|
>>> safe_int = except_(ValueError)(int)
|
|
>>> safe_int('five')
|
|
>>> safe_int('5')
|
|
5
|
|
|
|
Specify a literal replacement with ``replace``.
|
|
|
|
>>> safe_int_r = except_(ValueError, replace=0)(int)
|
|
>>> safe_int_r('five')
|
|
0
|
|
|
|
Provide an expression to ``use`` to pass through particular parameters.
|
|
|
|
>>> safe_int_pt = except_(ValueError, use='args[0]')(int)
|
|
>>> safe_int_pt('five')
|
|
'five'
|
|
|
|
"""
|
|
|
|
def decorate(func):
|
|
@functools.wraps(func)
|
|
def wrapper(*args, **kwargs):
|
|
try:
|
|
return func(*args, **kwargs)
|
|
except exceptions:
|
|
try:
|
|
return eval(use)
|
|
except TypeError:
|
|
return replace
|
|
|
|
return wrapper
|
|
|
|
return decorate
|