Commit 5d7bb4c8 authored by gabrieldemarmiesse's avatar gabrieldemarmiesse

removed the recommendation of subclassing.

parent 32322030
......@@ -45,8 +45,10 @@ Static Attributes
Attributes of an extension type are stored directly in the object's C struct.
The set of attributes is fixed at compile time; you can't add attributes to an
extension type instance at run time simply by assigning to them, as you could
with a Python class instance. (You can subclass the extension type in Python
and add attributes to instances of the subclass, see :ref:`dynamic_attributes`.)
with a Python class instance. However, you can explicitly enable support
for dynamically assigned attributes, or subclass the extension type with a normal
Python class, which then supports arbitrary attribute assignments.
See :ref:`dynamic_attributes`.
There are two ways that attributes of an extension type can be accessed: by
Python attribute lookup, or by direct access to the C struct from Cython code.
......@@ -84,11 +86,9 @@ Dynamic Attributes
It is not possible to add attributes to an extension type at runtime by default.
You have two ways of avoiding this limitation, both add an overhead when
a method is called from Python code.
a method is called from Python code. Especially when calling ``cpdef`` methods.
The first workaround is making a child Python class and is preferred way of
keeping the static attributes of an extension
type while enabling the use of dynamic attributes::
The first approach is to create a Python subclass.::
cdef class Animal:
......@@ -105,9 +105,7 @@ type while enabling the use of dynamic attributes::
dog.has_tail = True
Declaring a ``__dict__`` attribute is the second way of enabling dynamic attributes
and can have a significant performance penalty compared to subclassing,
especially when using ``cpdef`` class methods::
Declaring a ``__dict__`` attribute is the second way of enabling dynamic attributes.::
cdef class Animal:
......
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