1 from operator import itemgetter as _itemgetter
2 from keyword import iskeyword as _iskeyword
6 _multiprocess_can_split_ = True
7 """Allow nosetests to split tests between processes.
11 def namedtuple(typename, field_names, verbose=False):
12 """Returns a new subclass of tuple with named fields.
14 >>> Point = namedtuple('Point', 'x y')
15 >>> Point.__doc__ # docstring for the new class
17 >>> p = Point(11, y=22) # instantiate with positional args or keywords
18 >>> p[0] + p[1] # indexable like a plain tuple
20 >>> x, y = p # unpack like a regular tuple
23 >>> p.x + p.y # fields also accessable by name
25 >>> d = p._asdict() # convert to a dictionary
28 >>> Point(**d) # convert from a dictionary
30 >>> p._replace(x=100) # _replace() is like str.replace() but targets named fields
35 # Parse and validate the field names. Validation serves two purposes,
36 # generating informative error messages and preventing template injection attacks.
37 if isinstance(field_names, basestring):
38 field_names = field_names.replace(',', ' ').split() # names separated by whitespace and/or commas
39 field_names = tuple(map(str, field_names))
40 for name in (typename,) + field_names:
41 if not all(c.isalnum() or c=='_' for c in name):
42 raise ValueError('Type names and field names can only contain alphanumeric characters and underscores: %r' % name)
44 raise ValueError('Type names and field names cannot be a keyword: %r' % name)
46 raise ValueError('Type names and field names cannot start with a number: %r' % name)
48 for name in field_names:
49 if name.startswith('_'):
50 raise ValueError('Field names cannot start with an underscore: %r' % name)
51 if name in seen_names:
52 raise ValueError('Encountered duplicate field name: %r' % name)
55 # Create and fill-in the class template
56 numfields = len(field_names)
57 argtxt = repr(field_names).replace("'", "")[1:-1] # tuple repr without parens or quotes
58 reprtxt = ', '.join('%s=%%r' % name for name in field_names)
59 dicttxt = ', '.join('%r: t[%d]' % (name, pos) for pos, name in enumerate(field_names))
60 template = '''class %(typename)s(tuple):
61 '%(typename)s(%(argtxt)s)' \n
63 _fields = %(field_names)r \n
64 def __new__(_cls, %(argtxt)s):
65 return _tuple.__new__(_cls, (%(argtxt)s)) \n
67 def _make(cls, iterable, new=tuple.__new__, len=len):
68 'Make a new %(typename)s object from a sequence or iterable'
69 result = new(cls, iterable)
70 if len(result) != %(numfields)d:
71 raise TypeError('Expected %(numfields)d arguments, got %%d' %% len(result))
74 return '%(typename)s(%(reprtxt)s)' %% self \n
76 'Return a new dict which maps field names to their values'
77 return {%(dicttxt)s} \n
78 def _replace(_self, **kwds):
79 'Return a new %(typename)s object replacing specified fields with new values'
80 result = _self._make(map(kwds.pop, %(field_names)r, _self))
82 raise ValueError('Got unexpected field names: %%r' %% kwds.keys())
84 def __getnewargs__(self):
85 return tuple(self) \n\n''' % locals()
86 for i, name in enumerate(field_names):
87 template += ' %s = _property(_itemgetter(%d))\n' % (name, i)
91 # Execute the template string in a temporary namespace and
92 # support tracing utilities by setting a value for frame.f_globals['__name__']
93 namespace = dict(_itemgetter=_itemgetter, __name__='namedtuple_%s' % typename,
94 _property=property, _tuple=tuple)
96 exec template in namespace
97 except SyntaxError, e:
98 raise SyntaxError(e.message + ':\n' + template)
99 result = namespace[typename]
101 # For pickling to work, the __module__ variable needs to be set to the frame
102 # where the named tuple is created. Bypass this step in enviroments where
103 # sys._getframe is not defined (Jython for example).
104 if hasattr(_sys, '_getframe'):
105 result.__module__ = _sys._getframe(1).f_globals.get('__name__', '__main__')