typedef struct {
    PyObject_HEAD
    ...etc.             /* a dictionary instance */
} mappingobject;

static int mapping_length(mappingobject *mp);
static PyObject *mapping_subscript(mappingobject *mp, PyObject *key);
static int mapping_ass_sub(mappingobject *mp, PyObject *key, PyObject *value);


static PyMappingMethods mapping_as_mapping = {  /* mapping type supplement */
        (inquiry)       mapping_length,         /* mp_length        'len(x)'  */
        (binaryfunc)    mapping_subscript,      /* mp_subscript     'x[k]'    */
        (objobjargproc) mapping_ass_sub,        /* mp_ass_subscript 'x[k] = v'*/
};

static struct PyMethodDef mapp_methods[] = {    /* dictionary methods */
        {"has_key",     mapping_has_key},       /* 'dict.has_key(k)'  */
        {"items",       mapping_items},         /* 'dict.items()'     */
        {"keys",        mapping_keys},          /* 'dict.keys()'      */
        {"values",      mapping_values},        /* 'dict.values()'    */
        {NULL,          NULL} 
};

static PyObject *mapping_getattr(mappingobject *mp, char *name)
{
        return Py_FindMethod(mapp_methods, (PyObject *)mp, name);
}

PyTypeObject Mappingtype = {                /* dictionary type-descriptor */
        PyObject_HEAD_INIT(&PyType_Type)    /* shared by all instances    */
        0,
        "dictionary",
        sizeof(mappingobject),
        0,
        (destructor)mapping_dealloc,    /* tp_dealloc */
        (printfunc)mapping_print,       /* tp_print */
        (getattrfunc)mapping_getattr,   /* tp_getattr: search method table */
        0,                              /* tp_setattr: no mutable attributes */
        (cmpfunc)mapping_compare,       /* tp_compare */
        (reprfunc)mapping_repr,         /* tp_repr */
        0,                              /* tp_as_number */
        0,                              /* tp_as_sequence */
        &mapping_as_mapping,            /* tp_as_mapping: the operator link */
};                                      /* the rest are all zero (unused) */