Mercurial > repos > guerler > springsuite
diff planemo/lib/python3.7/site-packages/future/builtins/newnext.py @ 0:d30785e31577 draft
"planemo upload commit 6eee67778febed82ddd413c3ca40b3183a3898f1"
author | guerler |
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date | Fri, 31 Jul 2020 00:18:57 -0400 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/planemo/lib/python3.7/site-packages/future/builtins/newnext.py Fri Jul 31 00:18:57 2020 -0400 @@ -0,0 +1,70 @@ +''' +This module provides a newnext() function in Python 2 that mimics the +behaviour of ``next()`` in Python 3, falling back to Python 2's behaviour for +compatibility if this fails. + +``newnext(iterator)`` calls the iterator's ``__next__()`` method if it exists. If this +doesn't exist, it falls back to calling a ``next()`` method. + +For example: + + >>> class Odds(object): + ... def __init__(self, start=1): + ... self.value = start - 2 + ... def __next__(self): # note the Py3 interface + ... self.value += 2 + ... return self.value + ... def __iter__(self): + ... return self + ... + >>> iterator = Odds() + >>> next(iterator) + 1 + >>> next(iterator) + 3 + +If you are defining your own custom iterator class as above, it is preferable +to explicitly decorate the class with the @implements_iterator decorator from +``future.utils`` as follows: + + >>> @implements_iterator + ... class Odds(object): + ... # etc + ... pass + +This next() function is primarily for consuming iterators defined in Python 3 +code elsewhere that we would like to run on Python 2 or 3. +''' + +_builtin_next = next + +_SENTINEL = object() + +def newnext(iterator, default=_SENTINEL): + """ + next(iterator[, default]) + + Return the next item from the iterator. If default is given and the iterator + is exhausted, it is returned instead of raising StopIteration. + """ + + # args = [] + # if default is not _SENTINEL: + # args.append(default) + try: + try: + return iterator.__next__() + except AttributeError: + try: + return iterator.next() + except AttributeError: + raise TypeError("'{0}' object is not an iterator".format( + iterator.__class__.__name__)) + except StopIteration as e: + if default is _SENTINEL: + raise e + else: + return default + + +__all__ = ['newnext']