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| """ | |
| Module defining global singleton classes. | |
| This module raises a RuntimeError if an attempt to reload it is made. In that | |
| way the identities of the classes defined here are fixed and will remain so | |
| even if numpy itself is reloaded. In particular, a function like the following | |
| will still work correctly after numpy is reloaded:: | |
| def foo(arg=np._NoValue): | |
| if arg is np._NoValue: | |
| ... | |
| That was not the case when the singleton classes were defined in the numpy | |
| ``__init__.py`` file. See gh-7844 for a discussion of the reload problem that | |
| motivated this module. | |
| """ | |
| __ALL__ = [ | |
| 'ModuleDeprecationWarning', 'VisibleDeprecationWarning', '_NoValue' | |
| ] | |
| # Disallow reloading this module so as to preserve the identities of the | |
| # classes defined here. | |
| if '_is_loaded' in globals(): | |
| raise RuntimeError('Reloading numpy._globals is not allowed') | |
| _is_loaded = True | |
| class ModuleDeprecationWarning(DeprecationWarning): | |
| """Module deprecation warning. | |
| The nose tester turns ordinary Deprecation warnings into test failures. | |
| That makes it hard to deprecate whole modules, because they get | |
| imported by default. So this is a special Deprecation warning that the | |
| nose tester will let pass without making tests fail. | |
| """ | |
| ModuleDeprecationWarning.__module__ = 'numpy' | |
| class VisibleDeprecationWarning(UserWarning): | |
| """Visible deprecation warning. | |
| By default, python will not show deprecation warnings, so this class | |
| can be used when a very visible warning is helpful, for example because | |
| the usage is most likely a user bug. | |
| """ | |
| VisibleDeprecationWarning.__module__ = 'numpy' | |
| class _NoValueType: | |
| """Special keyword value. | |
| The instance of this class may be used as the default value assigned to a | |
| keyword if no other obvious default (e.g., `None`) is suitable, | |
| Common reasons for using this keyword are: | |
| - A new keyword is added to a function, and that function forwards its | |
| inputs to another function or method which can be defined outside of | |
| NumPy. For example, ``np.std(x)`` calls ``x.std``, so when a ``keepdims`` | |
| keyword was added that could only be forwarded if the user explicitly | |
| specified ``keepdims``; downstream array libraries may not have added | |
| the same keyword, so adding ``x.std(..., keepdims=keepdims)`` | |
| unconditionally could have broken previously working code. | |
| - A keyword is being deprecated, and a deprecation warning must only be | |
| emitted when the keyword is used. | |
| """ | |
| __instance = None | |
| def __new__(cls): | |
| # ensure that only one instance exists | |
| if not cls.__instance: | |
| cls.__instance = super().__new__(cls) | |
| return cls.__instance | |
| # needed for python 2 to preserve identity through a pickle | |
| def __reduce__(self): | |
| return (self.__class__, ()) | |
| def __repr__(self): | |
| return "<no value>" | |
| _NoValue = _NoValueType() | |