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import collections.abc
import functools
# from jaraco.functools 3.5
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
# from jaraco.functools 4.0
@functools.singledispatch
def _splat_inner(args, func):
"""Splat args to func."""
return func(*args)
@_splat_inner.register
def _(args: collections.abc.Mapping, func):
"""Splat kargs to func as kwargs."""
return func(**args)
def splat(func):
"""
Wrap func to expect its parameters to be passed positionally in a tuple.
Has a similar effect to that of ``itertools.starmap`` over
simple ``map``.
>>> import itertools, operator
>>> pairs = [(-1, 1), (0, 2)]
>>> _ = tuple(itertools.starmap(print, pairs))
-1 1
0 2
>>> _ = tuple(map(splat(print), pairs))
-1 1
0 2
The approach generalizes to other iterators that don't have a "star"
equivalent, such as a "starfilter".
>>> list(filter(splat(operator.add), pairs))
[(0, 2)]
Splat also accepts a mapping argument.
>>> def is_nice(msg, code):
... return "smile" in msg or code == 0
>>> msgs = [
... dict(msg='smile!', code=20),
... dict(msg='error :(', code=1),
... dict(msg='unknown', code=0),
... ]
>>> for msg in filter(splat(is_nice), msgs):
... print(msg)
{'msg': 'smile!', 'code': 20}
{'msg': 'unknown', 'code': 0}
"""
return functools.wraps(func)(functools.partial(_splat_inner, func=func))
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