Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Browse files

Added special methods info from pyrex, begun documenting the pxd pack…

…ages
  • Loading branch information...
commit df797e1b411f00b20ee040cb180ec852794131c9 1 parent e23da12
ggellner@giton authored
49 docs/pxd_package.rst
View
@@ -0,0 +1,49 @@
+I think this is a result of a recent change to Pyrex that
+has been merged into Cython.
+
+If a directory contains an :file:`__init__.py` or :file:`__init__.pyx` file,
+it's now assumed to be a package directory. So, for example,
+if you have a directory structure::
+
+ foo/
+ __init__.py
+ shrubbing.pxd
+ shrubbing.pyx
+
+then the shrubbing module is assumed to belong to a package
+called 'foo', and its fully qualified module name is
+'foo.shrubbing'.
+
+So when Pyrex wants to find out whether there is a `.pxd` file for shrubbing,
+it looks for one corresponding to a module called :module:`foo.shrubbing`. It
+does this by searching the include path for a top-level package directory
+called 'foo' containing a file called 'shrubbing.pxd'.
+
+However, if foo is the current directory you're running
+the compiler from, and you haven't added foo to the
+include path using a -I option, then it won't be on
+the include path, and the `.pxd` won't be found.
+
+What to do about this depends on whether you really
+intend the module to reside in a package.
+
+If you intend shrubbing to be a top-level module, you
+will have to move it somewhere else where there is
+no :file:`__init__.*` file.
+
+If you do intend it to reside in a package, then there
+are two alternatives:
+
+1. cd to the directory containing foo and compile
+ from there::
+
+ cd ..; cython foo/shrubbing.pyx
+
+2. arrange for the directory containing foo to be
+ passed as a -I option, e.g.::
+
+ cython -I .. shrubbing.pyx
+
+Arguably this behaviour is not very desirable, and I'll
+see if I can do something about it.
+
5 docs/pyrex_differences.rst
View
@@ -6,11 +6,6 @@
Differences between Cython and Pyrex
**************************************
-Package names and cross-directory imports
-==========================================
-
-Just like in python.
-
List Comprehensions
====================
314 docs/special_methods.rst
View
@@ -0,0 +1,314 @@
+Special Methods of Extension Types
+===================================
+
+This page describes the special methods currently supported by Pyrex extension
+types. A complete list of all the special methods appears in the table at the
+bottom. Some of these methods behave differently from their Python
+counterparts or have no direct Python counterparts, and require special
+mention.
+
+.. Note: Everything said on this page applies only to extension types, defined
+ with the :keyword:`cdef class` statement. It doesn't apply to classes defined with the
+ Python :keyword:`class` statement, where the normal Python rules apply.
+
+Declaration
+------------
+Special methods of extension types must be declared with :keyword:`def`, not
+:keyword:`cdef`.
+
+Docstrings
+-----------
+
+Currently, docstrings are not fully supported in special methods of extension
+types. You can place a docstring in the source to serve as a comment, but it
+won't show up in the corresponding :attr:`__doc__` attribute at run time. (This is a
+Python limitation -- there's nowhere in the `PyTypeObject` data structure to put
+such docstrings.)
+
+Initialisation methods: :meth:`__cinit__` and :meth:`__init__`
+---------------------------------------------------------------
+There are two methods concerned with initialising the object.
+
+The :meth:`__cinit__` method is where you should perform basic C-level
+initialisation of the object, including allocation of any C data structures
+that your object will own. You need to be careful what you do in the
+:meth:`__cinit__` method, because the object may not yet be a valid Python
+object when it is called. Therefore, you must not invoke any Python operations
+which might touch the object; in particular, do not try to call any of its
+methods.
+
+By the time your :meth:`__cinit__` method is called, memory has been allocated for the
+object and any C attributes it has have been initialised to 0 or null. (Any
+Python attributes have also been initialised to None, but you probably
+shouldn't rely on that.) Your :meth:`__cinit__` method is guaranteed to be called
+exactly once.
+
+If your extension type has a base type, the :meth:`__cinit__` method of the base type
+is automatically called before your :meth:`__cinit__` method is called; you cannot
+explicitly call the inherited :meth:`__cinit__` method. If you need to pass a modified
+argument list to the base type, you will have to do the relevant part of the
+initialisation in the :meth:`__init__` method instead (where the normal rules for
+calling inherited methods apply).
+
+Any initialisation which cannot safely be done in the :meth:`__cinit__` method should
+be done in the :meth:`__init__` method. By the time :meth:`__init__` is called, the object is
+a fully valid Python object and all operations are safe. Under some
+circumstances it is possible for :meth:`__init__` to be called more than once or not
+to be called at all, so your other methods should be designed to be robust in
+such situations.
+
+Any arguments passed to the constructor will be passed to both the
+:meth:`__cinit__` method and the :meth:`__init__` method. If you anticipate
+subclassing your extension type in Python, you may find it useful to give the
+:meth:`__cinit__` method `*` and `**` arguments so that it can accept and
+ignore extra arguments. Otherwise, any Python subclass which has an
+:meth:`__init__` with a different signature will have to override
+:meth:`__new__` as well as :meth:`__init__`, which the writer of a Python
+class wouldn't expect to have to do. Finalization method: :meth:`__dealloc__`
+The counterpart to the :meth:`__cinit__` method is the :meth:`__dealloc__`
+method, which should perform the inverse of the :meth:`__cinit__` method. Any
+C data structures that you allocated in your :meth:`__cinit__` method should
+be freed in your :meth:`__dealloc__` method.
+
+You need to be careful what you do in a :meth:`__dealloc__` method. By the time your
+:meth:`__dealloc__` method is called, the object may already have been partially
+destroyed and may not be in a valid state as far as Python is concerned, so
+you should avoid invoking any Python operations which might touch the object.
+In particular, don't call any other methods of the object or do anything which
+might cause the object to be resurrected. It's best if you stick to just
+deallocating C data.
+
+You don't need to worry about deallocating Python attributes of your object,
+because that will be done for you by Pyrex after your :meth:`__dealloc__` method
+returns.
+
+.. Note: There is no :meth:`__del__` method for extension types.
+
+Arithmetic methods
+-------------------
+
+Arithmetic operator methods, such as :meth:`__add__`, behave differently from their
+Python counterparts. There are no separate "reversed" versions of these
+methods (:meth:`__radd__`, etc.) Instead, if the first operand cannot perform the
+operation, the same method of the second operand is called, with the operands
+in the same order.
+
+This means that you can't rely on the first parameter of these methods being
+"self", and you should test the types of both operands before deciding what to
+do. If you can't handle the combination of types you've been given, you should
+return `NotImplemented`.
+
+This also applies to the in-place arithmetic method :meth:`__ipow__`. It doesn't apply
+to any of the other in-place methods (:meth:`__iadd__`, etc.) which always
+take `self` as the first argument.
+
+Rich comparisons
+-----------------
+
+There are no separate methods for the individual rich comparison operations
+(:meth:`__eq__`, :meth:`__le__`, etc.) Instead there is a single method
+:meth:`__richcmp__` which takes an integer indicating which operation is to be
+performed, as follows:
+
++-----+-----+
+| < | 0 |
++-----+-----+
+| == | 2 |
++-----+-----+
+| > | 4 |
++-----+-----+
+| <= | 1 |
++-----+-----+
+| != | 3 |
++-----+-----+
+| >= | 5 |
++-----+-----+
+
+The :meth:`__next__` method
+----------------------------
+
+Extension types wishing to implement the iterator interface should define a
+method called :meth:`__next__`, not next. The Python system will automatically
+supply a next method which calls your :meth:`__next__`. Do *NOT* explicitly
+give your type a next method, or bad things could happen.
+
+Type Testing in Special Methods
+--------------------------------
+
+.. TODO document the Cython way using the overridden isinstance
+
+
+Special Method Table
+---------------------
+
+This table lists all of the special methods together with their parameter and
+return types. In the table below, a parameter name of self is used to indicate
+that the parameter has the type that the method belongs to. Other parameters
+with no type specified in the table are generic Python objects.
+
+You don't have to declare your method as taking these parameter types. If you
+declare different types, conversions will be performed as necessary.
+
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| Name | Parameters | Return type | Description |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| General |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __cinit__ |self, ... | | Basic initialisation (no direct Python equivalent) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __init__ |self, ... | | Further initialisation |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __dealloc__ |self | | Basic deallocation (no direct Python equivalent) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __cmp__ |x, y | int | 3-way comparison |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __richcmp__ |x, y, int op | object | Rich comparison (no direct Python equivalent) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __str__ |self | object | str(self) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __repr__ |self | object | repr(self) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __hash__ |self | int | Hash function |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __call__ |self, ... | object | self(...) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __iter__ |self | object | Return iterator for sequence |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __getattr__ |self, name | object | Get attribute |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __setattr__ |self, name, val | | Set attribute |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __delattr__ |self, name | | Delete attribute |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| Arithmetic operators |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __add__ | x, y | object | binary `+` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __sub__ | x, y | object | binary `-` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __mul__ | x, y | object | `*` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __div__ | x, y | object | `/` operator for old-style division |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __floordiv__ | x, y | object | `//` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __truediv__ | x, y | object | `/` operator for new-style division |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __mod__ | x, y | object | `%` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __divmod__ | x, y | object | combined div and mod |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __pow__ | x, y, z | object | `**` operator or pow(x, y, z) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __neg__ | self | object | unary `-` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __pos__ | self | object | unary `+` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __abs__ | self | object | absolute value |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __nonzero__ | self | int | convert to boolean |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __invert__ | self | object | `~` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __lshift__ | x, y | object | `<<` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __rshift__ | x, y | object | `>>` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __and__ | x, y | object | `&` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __or__ | x, y | object | `|` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __xor__ | x, y | object | `^` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| Numeric conversions |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __int__ | self | object | Convert to integer |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __long__ | self | object | Convert to long integer |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __float__ | self | object | Convert to float |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __oct__ | self | object | Convert to octal |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __hex__ | self | object | Convert to hexadecimal |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __index__ (2.5+ only) | self | object | Convert to sequence index |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| In-place arithmetic operators |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __iadd__ | self, x | object | `+=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __isub__ | self, x | object | `-=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __imul__ | self, x | object | `*=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __idiv__ | self, x | object | `/=` operator for old-style division |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __ifloordiv__ | self, x | object | `//=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __itruediv__ | self, x | object | `/=` operator for new-style division |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __imod__ | self, x | object | `%=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __ipow__ | x, y, z | object | `**=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __ilshift__ | self, x | object | `<<=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __irshift__ | self, x | object | `>>=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __iand__ | self, x | object | `&=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __ior__ | self, x | object | `|=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __ixor__ | self, x | object | `^=` operator |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| Sequences and mappings |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __len__ | self int | | len(self) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __getitem__ | self, x | object | self[x] |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __setitem__ | self, x, y | | self[x] = y |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __delitem__ | self, x | | del self[x] |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __getslice__ | self, Py_ssize_t i, Py_ssize_t j | object | self[i:j] |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __setslice__ | self, Py_ssize_t i, Py_ssize_t j, x | | self[i:j] = x |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __delslice__ | self, Py_ssize_t i, Py_ssize_t j | | del self[i:j] |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __contains__ | self, x | int | x in self |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| Iterators |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __next__ | self | object | Get next item (called next in Python) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| Buffer interface (no Python equivalents - see note 1) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __getreadbuffer__ | self, int i, void `**p` | | |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __getwritebuffer__ | self, int i, void `**p` | | |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __getsegcount__ | self, int `*p` | | |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __getcharbuffer__ | self, int i, char `**p` | | |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| Descriptor objects (see note 2) |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __get__ | self, instance, class | object | Get value of attribute |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __set__ | self, instance, value | | Set value of attribute |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+| __delete__ | self, instance | | Delete attribute |
++-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
+
+.. note:: (1) The buffer interface is intended for use by C code and is not directly
+ accessible from Python. It is described in the Python/C API Reference Manual
+ under sections 6.6 and 10.6.
+
+.. note:: (2) Descriptor objects are part of the support mechanism for new-style
+ Python classes. See the discussion of descriptors in the Python documentation.
+ See also PEP 252, "Making Types Look More Like Classes", and PEP 253,
+ "Subtyping Built-In Types".
+
1  index.rst
View
@@ -12,6 +12,7 @@ Contents:
docs/numpy_tutorial
docs/language_basics
docs/extension_types
+ docs/special_methods
docs/sharing_declarations
docs/external_C_code
docs/source_files_and_compilation
BIN  sphinxext/cython_highlighting.pyc
View
Binary file not shown
BIN  sphinxext/ipython_console_highlighting.pyc
View
Binary file not shown
Please sign in to comment.
Something went wrong with that request. Please try again.