| """functools.py - Tools for working with functions and callable objects |
| """ |
| # Python module wrapper for _functools C module |
| # to allow utilities written in Python to be added |
| # to the functools module. |
| # Written by Nick Coghlan <ncoghlan at gmail.com> |
| # Copyright (C) 2006 Python Software Foundation. |
| # See C source code for _functools credits/copyright |
| |
| from _functools import partial, reduce |
| |
| # update_wrapper() and wraps() are tools to help write |
| # wrapper functions that can handle naive introspection |
| |
| WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__doc__') |
| WRAPPER_UPDATES = ('__dict__',) |
| def update_wrapper(wrapper, |
| wrapped, |
| assigned = WRAPPER_ASSIGNMENTS, |
| updated = WRAPPER_UPDATES): |
| """Update a wrapper function to look like the wrapped function |
| |
| wrapper is the function to be updated |
| wrapped is the original function |
| assigned is a tuple naming the attributes assigned directly |
| from the wrapped function to the wrapper function (defaults to |
| functools.WRAPPER_ASSIGNMENTS) |
| updated is a tuple naming the attributes of the wrapper that |
| are updated with the corresponding attribute from the wrapped |
| function (defaults to functools.WRAPPER_UPDATES) |
| """ |
| for attr in assigned: |
| setattr(wrapper, attr, getattr(wrapped, attr)) |
| for attr in updated: |
| getattr(wrapper, attr).update(getattr(wrapped, attr, {})) |
| # Return the wrapper so this can be used as a decorator via partial() |
| return wrapper |
| |
| def wraps(wrapped, |
| assigned = WRAPPER_ASSIGNMENTS, |
| updated = WRAPPER_UPDATES): |
| """Decorator factory to apply update_wrapper() to a wrapper function |
| |
| Returns a decorator that invokes update_wrapper() with the decorated |
| function as the wrapper argument and the arguments to wraps() as the |
| remaining arguments. Default arguments are as for update_wrapper(). |
| This is a convenience function to simplify applying partial() to |
| update_wrapper(). |
| """ |
| return partial(update_wrapper, wrapped=wrapped, |
| assigned=assigned, updated=updated) |
| |
| def total_ordering(cls): |
| """Class decorator that fills in missing ordering methods""" |
| convert = { |
| '__lt__': [('__gt__', lambda self, other: other < self), |
| ('__le__', lambda self, other: not other < self), |
| ('__ge__', lambda self, other: not self < other)], |
| '__le__': [('__ge__', lambda self, other: other <= self), |
| ('__lt__', lambda self, other: not other <= self), |
| ('__gt__', lambda self, other: not self <= other)], |
| '__gt__': [('__lt__', lambda self, other: other > self), |
| ('__ge__', lambda self, other: not other > self), |
| ('__le__', lambda self, other: not self > other)], |
| '__ge__': [('__le__', lambda self, other: other >= self), |
| ('__gt__', lambda self, other: not other >= self), |
| ('__lt__', lambda self, other: not self >= other)] |
| } |
| roots = set(dir(cls)) & set(convert) |
| if not roots: |
| raise ValueError('must define at least one ordering operation: < > <= >=') |
| root = max(roots) # prefer __lt__ to __le__ to __gt__ to __ge__ |
| for opname, opfunc in convert[root]: |
| if opname not in roots: |
| opfunc.__name__ = opname |
| opfunc.__doc__ = getattr(int, opname).__doc__ |
| setattr(cls, opname, opfunc) |
| return cls |
| |
| def cmp_to_key(mycmp): |
| """Convert a cmp= function into a key= function""" |
| class K(object): |
| def __init__(self, obj, *args): |
| self.obj = obj |
| def __lt__(self, other): |
| return mycmp(self.obj, other.obj) < 0 |
| def __gt__(self, other): |
| return mycmp(self.obj, other.obj) > 0 |
| def __eq__(self, other): |
| return mycmp(self.obj, other.obj) == 0 |
| def __le__(self, other): |
| return mycmp(self.obj, other.obj) <= 0 |
| def __ge__(self, other): |
| return mycmp(self.obj, other.obj) >= 0 |
| def __ne__(self, other): |
| return mycmp(self.obj, other.obj) != 0 |
| def __hash__(self): |
| raise TypeError('hash not implemented') |
| return K |