python datatype factory

datatype.py

#!/usr/bin/env python2.7

import itertools


def datatype(type_name, params):
  """A faster/more efficient namedtuple replacement with better subclassing properties.

      >>> RustLibrary = datatype('RustLibrary', ['sources', 'dependencies'])
      >>> rl = RustLibrary([1,2,3], [4,5,6])
      >>> rl.sources
      [1, 2, 3]
      >>> rl.dependencies
      [4, 5, 6]
      >>> isinstance(rl, RustLibrary)
      True
  """
  class DataType(object):
    __slots__ = tuple(params)
    def __init__(self, *args):
      assert len(args) == len(params), 'invalid number of args'
      for kw, v in itertools.izip(params, args):
        setattr(self, kw, v)
  DataType.__name__ = type_name
  return DataType


class SubclassedThing(datatype('Superclass', ['a', 'b', 'c'])):
  @property
  def product(self):
    return self.a * self.b * self.c