diff options
Diffstat (limited to 'Lib')
| -rw-r--r-- | Lib/collections/__init__.py | 111 |
1 files changed, 60 insertions, 51 deletions
diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py index 7e249db..b429599 100644 --- a/Lib/collections/__init__.py +++ b/Lib/collections/__init__.py @@ -233,10 +233,58 @@ class OrderedDict(dict): ### namedtuple ################################################################################ +_class_template = '''\ +class {typename}(tuple): + '{typename}({arg_list})' + + __slots__ = () + + _fields = {field_names!r} + + def __new__(_cls, {arg_list}): + 'Create new instance of {typename}({arg_list})' + return _tuple.__new__(_cls, ({arg_list})) + + @classmethod + def _make(cls, iterable, new=tuple.__new__, len=len): + 'Make a new {typename} object from a sequence or iterable' + result = new(cls, iterable) + if len(result) != {num_fields:d}: + raise TypeError('Expected {num_fields:d} arguments, got %d' % len(result)) + return result + + def __repr__(self): + 'Return a nicely formatted representation string' + return self.__class__.__name__ + '({repr_fmt})' % self + + def _asdict(self): + 'Return a new OrderedDict which maps field names to their values' + return OrderedDict(zip(self._fields, self)) + + def _replace(_self, **kwds): + 'Return a new {typename} 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 + + def __getnewargs__(self): + 'Return self as a plain tuple. Used by copy and pickle.' + return tuple(self) + +{field_defs} +''' + +_repr_template = '{name}=%r' + +_field_template = '''\ + {name} = _property(_itemgetter({index:d}), doc='Alias for field number {index:d}') +''' + def namedtuple(typename, field_names, verbose=False, rename=False): """Returns a new subclass of tuple with named fields. - >>> Point = namedtuple('Point', 'x y') + >>> 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 @@ -287,66 +335,27 @@ def namedtuple(typename, field_names, verbose=False, rename=False): raise ValueError('Encountered duplicate field name: %r' % name) seen_names.add(name) - # Create and fill-in the class template - template = '''class {typename}(tuple): - '{typename}({argtxt})' - - __slots__ = () - - _fields = {field_names!r} - - def __new__(_cls, {argtxt}): - 'Create new instance of {typename}({argtxt})' - return _tuple.__new__(_cls, ({argtxt})) - - @classmethod - def _make(cls, iterable, new=tuple.__new__, len=len): - 'Make a new {typename} 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 - - def __repr__(self): - 'Return a nicely formatted representation string' - return self.__class__.__name__ + '({reprtxt})' % self - - def _asdict(self): - 'Return a new OrderedDict which maps field names to their values' - return OrderedDict(zip(self._fields, self)) - - def _replace(_self, **kwds): - 'Return a new {typename} 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 - - def __getnewargs__(self): - 'Return self as a plain tuple. Used by copy and pickle.' - return tuple(self) - -''' - template = template.format( + # Fill-in the class template + class_definition = _class_template.format( typename = typename, field_names = field_names, - argtxt = repr(field_names).replace("'", "")[1:-1], - numfields = len(field_names), - reprtxt = ', '.join('{}=%r'.format(name) for name in field_names), + num_fields = len(field_names), + arg_list = repr(field_names).replace("'", "")[1:-1], + repr_fmt = ', '.join(_repr_template.format(name=name) for name in field_names), + field_defs = '\n'.join(_field_template.format(index=index, name=name) + for index, name in enumerate(field_names)) ) - for i, name in enumerate(field_names): - template += " %s = _property(_itemgetter(%d), doc='Alias for field number %d')\n" % (name, i, i) if verbose: - print(template) + print(class_definition) - # Execute the template string in a temporary namespace and + # Execute the class definition string in a temporary namespace and # support tracing utilities by setting a value for frame.f_globals['__name__'] namespace = dict(_itemgetter=_itemgetter, __name__='namedtuple_%s' % typename, OrderedDict=OrderedDict, _property=property, _tuple=tuple) try: - exec(template, namespace) + exec(class_definition, namespace) except SyntaxError as e: - raise SyntaxError(e.msg + ':\n\n' + template) + raise SyntaxError(e.msg + ':\n\n' + class_definition) result = namespace[typename] # For pickling to work, the __module__ variable needs to be set to the frame |