[Python-Dev] Code comprehensibility patch

[David Abrahams]

----- Original Message -----
From: "Tim Peters" <tim.one@comcast.net>


> > A long time ago I wrote to Guido suggesting that I might like to
submit
> > some patches to improve the comprehensibility of the Python source.
> > ...
> > I hope it looks like an improvement to people, but please let me
know
> > if it does not.
>
> I assume there was something wrong with the patch as posted, as it
looked
> like the new code used 1-space indents.  It also looked like it was
made
> against an out-of-date version of typeobject.c (please use current CVS
as a
> base -- the newer type/class code is unusually volatile).

Fixed. Comments appreciated. The new code is appended for easy perusal

-Dave

-----

static PyObject *
type_getattro(PyTypeObject *type, PyObject *name)
{
  PyTypeObject *metatype = type->ob_type;
  PyObject *meta_attribute, *attribute;
  descrgetfunc meta_get;

  /* Initialize this type (we'll assume the metatype is initialized) */
  if (type->tp_dict == NULL) {
    if (PyType_Ready(type) < 0)
      return NULL;
  }

  /* No readable descriptor found yet */
  meta_get = NULL;

  /* Look for the attribute in the metatype */
  meta_attribute = _PyType_Lookup(metatype, name);

  if (meta_attribute != NULL) {
    meta_get = meta_attribute->ob_type->tp_descr_get;

    if (meta_get != NULL && PyDescr_IsData(meta_attribute)) {
      /* Data descriptors implement tp_descr_set to intercept
       * writes. Assume the attribute is not overridden in
       * type's tp_dict (and bases): call the descriptor now.
       */
      return meta_get(meta_attribute,
              (PyObject *)type, (PyObject *)metatype);
    }
  }

  /* No data descriptor found on metatype. Look in tp_dict of this
   * type and its bases */
  attribute = _PyType_Lookup(type, name);
  if (attribute != NULL) {
    /* Implement descriptor functionality, if any */
    descrgetfunc local_get = attribute->ob_type->tp_descr_get;
    if (local_get != NULL) {
      /* NULL 2nd argument indicates the descriptor was found on
       * the target object itself (or a base)  */
      return local_get(attribute, (PyObject *)NULL, (PyObject *)type);
    }

    Py_INCREF(attribute);
    return attribute;
  }

  /* No attribute found in local __dict__ (or bases): use the
   * descriptor from the metatype, if any */
  if (meta_get != NULL)
    return meta_get(meta_attribute, (PyObject *)type, (PyObject
*)metatype);

  /* If an ordinary attribute was found on the metatype, return it now.
*/
  if (meta_attribute != NULL) {
    Py_INCREF(meta_attribute);
    return meta_attribute;
  }

  /* Give up */
  PyErr_Format(PyExc_AttributeError,
       "type object '%.50s' has no attribute '%.400s'",
       type->tp_name, PyString_AS_STRING(name));
  return NULL;
}