Hello, Another thoughts (and use cases) about namedtuple-DRY-matter and (what is more important) subclassing namedtuple() classes: Quite often I need to create my own named tuple class(es) with some additional methods or modifications of existing ones (most often: a custom version of __repr__()). Now I must write something like: _MyNamedTupleBase = namedtuple('MyNamedTuple', ('one_field', 'another_field', 'and_another_one')) class MyNamedTuple(_MyNamedTupleBase): def __repr__(self): "My sophisticated __repr__()" # and e.g. some new methods... ...or: class MyNamedTuple(namedtuple('MyNamedTuple', ('one_field', 'another_field', 'and_another_one'))): def __repr__(self): "My sophisticated __repr__()" # and e.g. some new methods... It would be very nice to be able to do it in such a way: class MyNamedTuple(namedtuple.abc): _fields = ( 'one_field', 'another_field', 'and_another_one', ) def __repr__(self): "My sophisticated __repr__()" # and e.g. some new methods... ...and especially: class MyAbstractNamedTuple(namedtuple.abc): def __repr__(self): "My sophisticated __repr__()" # and e.g. some new methods... class MyNamedTupleA(MyAbstractNamedTuple): _fields = 'a b c' class MyNamedTupleB(MyAbstractNamedTuple): _fields = ( 'one_field', 'another_field', 'and_another_one', ) (Please note that _fields is a part of the public API of named tuples). Implementation would be easy to explain (and to do; actually I have an outline in my head). The type (metaclass) of namedtuple.abc would be a subclass of abc.ABCMeta and would also act (by ABC registration mechanism) as an abstract base for all named tuples and structsequences like sys.version_info. So all these expressions would be True:
isinstance(namedtuple('Foo', 'x y z'), namedtuple.abc) isinstance(sys.version_info, namedtuple.abc)
And obviously:
isinstance(MyNamedTuple, namedtuple.abc) # referiring to the above examples
What do you think about the idea? Regards. *j