X-Git-Url: http://git.veekun.com/zzz-pokedex.git/blobdiff_plain/7677696cba1813630b653fe0af3338d37ea63730..53b6b2d57f58830d7aa3d416f2fa9192f6ff6c99:/pokedex/util.py diff --git a/pokedex/util.py b/pokedex/util.py new file mode 100644 index 0000000..5231259 --- /dev/null +++ b/pokedex/util.py @@ -0,0 +1,148 @@ +"""Functions missing from Python 2.5""" + +try: + from itertools import permutations +except ImportError: + # From the itertools documentation + def permutations(iterable, r=None): + # permutations('ABCD', 2) --> AB AC AD BA BC BD CA CB CD DA DB DC + # permutations(range(3)) --> 012 021 102 120 201 210 + pool = tuple(iterable) + n = len(pool) + r = n if r is None else r + if r > n: + return + indices = range(n) + cycles = range(n, n-r, -1) + yield tuple(pool[i] for i in indices[:r]) + while n: + for i in reversed(range(r)): + cycles[i] -= 1 + if cycles[i] == 0: + indices[i:] = indices[i+1:] + indices[i:i+1] + cycles[i] = n - i + else: + j = cycles[i] + indices[i], indices[-j] = indices[-j], indices[i] + yield tuple(pool[i] for i in indices[:r]) + break + else: + return + +try: + from collections import namedtuple +except ImportError: + # http://code.activestate.com/recipes/500261-named-tuples/ + from operator import itemgetter as _itemgetter + from keyword import iskeyword as _iskeyword + import sys as _sys + + def namedtuple(typename, field_names, verbose=False, rename=False): + """Returns a new subclass of tuple with named fields. + + >>> Point = namedtuple('Point', 'x y') + >>> Point.__doc__ # docstring for the new class + 'Point(x, y)' + >>> p = Point(11, y=22) # instantiate with positional args or keywords + >>> p[0] + p[1] # indexable like a plain tuple + 33 + >>> x, y = p # unpack like a regular tuple + >>> x, y + (11, 22) + >>> p.x + p.y # fields also accessable by name + 33 + >>> d = p._asdict() # convert to a dictionary + >>> d['x'] + 11 + >>> Point(**d) # convert from a dictionary + Point(x=11, y=22) + >>> p._replace(x=100) # _replace() is like str.replace() but targets named fields + Point(x=100, y=22) + + """ + + # Parse and validate the field names. Validation serves two purposes, + # generating informative error messages and preventing template injection attacks. + if isinstance(field_names, basestring): + field_names = field_names.replace(',', ' ').split() # names separated by whitespace and/or commas + field_names = tuple(map(str, field_names)) + if rename: + names = list(field_names) + seen = set() + for i, name in enumerate(names): + if (not min(c.isalnum() or c=='_' for c in name) or _iskeyword(name) + or not name or name[0].isdigit() or name.startswith('_') + or name in seen): + names[i] = '_%d' % i + seen.add(name) + field_names = tuple(names) + for name in (typename,) + field_names: + if not min(c.isalnum() or c=='_' for c in name): + raise ValueError('Type names and field names can only contain alphanumeric characters and underscores: %r' % name) + if _iskeyword(name): + raise ValueError('Type names and field names cannot be a keyword: %r' % name) + if name[0].isdigit(): + raise ValueError('Type names and field names cannot start with a number: %r' % name) + seen_names = set() + for name in field_names: + if name.startswith('_') and not rename: + raise ValueError('Field names cannot start with an underscore: %r' % name) + if name in seen_names: + raise ValueError('Encountered duplicate field name: %r' % name) + seen_names.add(name) + + # Create and fill-in the class template + numfields = len(field_names) + argtxt = repr(field_names).replace("'", "")[1:-1] # tuple repr without parens or quotes + reprtxt = ', '.join('%s=%%r' % name for name in field_names) + template = '''class %(typename)s(tuple): + '%(typename)s(%(argtxt)s)' \n + __slots__ = () \n + _fields = %(field_names)r \n + def __new__(_cls, %(argtxt)s): + return _tuple.__new__(_cls, (%(argtxt)s)) \n + @classmethod + def _make(cls, iterable, new=tuple.__new__, len=len): + 'Make a new %(typename)s object from a sequence or iterable' + result = new(cls, iterable) + if len(result) != %(numfields)d: + raise TypeError('Expected %(numfields)d arguments, got %%d' %% len(result)) + return result \n + def __repr__(self): + return '%(typename)s(%(reprtxt)s)' %% self \n + def _asdict(self): + 'Return a new dict which maps field names to their values' + return dict(zip(self._fields, self)) \n + def _replace(_self, **kwds): + 'Return a new %(typename)s object replacing specified fields with new values' + result = _self._make(map(kwds.pop, %(field_names)r, _self)) + if kwds: + raise ValueError('Got unexpected field names: %%r' %% kwds.keys()) + return result \n + def __getnewargs__(self): + return tuple(self) \n\n''' % locals() + for i, name in enumerate(field_names): + template += ' %s = _property(_itemgetter(%d))\n' % (name, i) + if verbose: + print template + + # Execute the template string in a temporary namespace + namespace = dict(_itemgetter=_itemgetter, __name__='namedtuple_%s' % typename, + _property=property, _tuple=tuple) + try: + exec template in namespace + except SyntaxError, e: + raise SyntaxError(e.message + ':\n' + template) + result = namespace[typename] + + # For pickling to work, the __module__ variable needs to be set to the frame + # where the named tuple is created. Bypass this step in enviroments where + # sys._getframe is not defined (Jython for example) or sys._getframe is not + # defined for arguments greater than 0 (IronPython). + try: + result.__module__ = _sys._getframe(1).f_globals.get('__name__', '__main__') + except (AttributeError, ValueError): + pass + + return result +