diff options
Diffstat (limited to 'Lib/typing.py')
| -rw-r--r-- | Lib/typing.py | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/Lib/typing.py b/Lib/typing.py index b798830..0aeb089 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -1959,7 +1959,22 @@ class NamedTupleMeta(type): raise TypeError("Class syntax for NamedTuple is only supported" " in Python 3.6+") types = ns.get('__annotations__', {}) - return _make_nmtuple(typename, types.items()) + nm_tpl = _make_nmtuple(typename, types.items()) + defaults = [] + defaults_dict = {} + for field_name in types: + if field_name in ns: + default_value = ns[field_name] + defaults.append(default_value) + defaults_dict[field_name] = default_value + elif defaults: + raise TypeError("Non-default namedtuple field {field_name} cannot follow default" + " field(s) {default_names}" + .format(field_name=field_name, + default_names=', '.join(defaults_dict.keys()))) + nm_tpl.__new__.__defaults__ = tuple(defaults) + nm_tpl._field_defaults = defaults_dict + return nm_tpl class NamedTuple(metaclass=NamedTupleMeta): """Typed version of namedtuple. |