Lines Matching full:classof
152 is through a small static member function ``classof``. In order to have
180 + static bool classof(const Shape *S) {
191 + static bool classof(const Shape *S) {
196 The job of ``classof`` is to dynamically determine whether an object of
199 ``classof`` in ``Derived`` which will accept an object of type ``Base``.
212 check roughly like ``Circle::classof(S)``. For more information, see
213 :ref:`classof-contract`.
215 The argument to ``classof`` should always be an *ancestor* class because
218 ``Foo`` automatically has a ``classof`` like:
225 static bool classof(const T *,
233 ``classof`` into ``Shape``: all relevant classes derive from ``Shape``,
235 so this notional inferred ``classof`` is all we need. See `Concrete
247 tree), the ``Kind`` check inside ``classof`` needs to be a bit more
254 * Since the class has children, the check inside ``classof`` must take them
269 Then in ``Square``, we would need to modify the ``classof`` like so:
273 - static bool classof(const Shape *S) {
276 + static bool classof(const Shape *S) {
283 ``Square``, and so ``classof`` needs to return ``true`` for them.
301 The example just given opens the door to bugs where the ``classof``\s are
318 Now, suppose that we forget to update ``Square::classof()``, so it still
323 static bool classof(const Shape *S) {
346 // Square::classof()
347 - static bool classof(const Shape *S) {
350 + static bool classof(const Shape *S) {
368 Notice that ``Square::classof`` does not need to be changed.
372 The Contract of ``classof``
375 To be more precise, let ``classof`` be inside a class ``C``. Then the
376 contract for ``classof`` is "return ``true`` if the dynamic type of the
392 #. The argument to ``classof`` should be a ``const Base *``, where ``Base``
397 ``classof`` that checks only against its ``Kind``.
399 ``classof`` that checks a range of the first child's ``Kind`` and the
