Cython-plus

===================

Bugs fixed
----------

* Crash when returning values on generator termination.

* In some cases, exceptions raised during internal isinstance() checks were
not propagated.

* Runtime reported file paths of source files (e.g for profiling and tracing)
are now relative to the build root directory instead of the main source file.

* Tracing exception handling code could enter the trace function with an active
exception set.

* The internal generator function type was not shared across modules.

* Comparisons of (inferred) ctuples failed to compile.

* Closures inside of cdef functions returning ``void`` failed to compile.

* Using ``const`` C++ references in intermediate parts of longer expressions
could fail to compile.

* C++ exception declarations with mapping functions could fail to compile when
pre-declared in .pxd files.

* C++ compilation could fail with an ambiguity error in recent MacOS-X Xcode
versions.

* C compilation could fail in pypy3.

* Fixed a memory leak in the compiler when compiling multiple modules.

* When compiling multiple modules, external library dependencies could leak
into later compiler runs. Fix by Jeroen Demeyer. This fixes ticket 845.

=================

Features added
--------------

* C functions can coerce to Python functions, which allows passing them
around as callable objects.

* C arrays can be assigned by value and auto-coerce from Python iterables
and to Python lists (and tuples).

* Extern C functions can now be declared as cpdef to export them to
the module's Python namespace. Extern C functions in pxd files export
their values to their own module, iff it exists.

* Anonymous C tuple types can be declared as (ctype1, ctype2, ...).

* `PEP 479 <https://www.python.org/dev/peps/pep-0479/>`_:
turn accidental StopIteration exceptions that exit generators
into a RuntimeError, activated with future import "generator_stop".

* Looping over ``reversed(range())`` is optimised in the same way as
``range()``. Patch by Favian Contreras.

Bugs fixed
----------

* Mismatching 'except' declarations on signatures in .pxd and .pyx files failed
to produce a compile error.

* Failure to find any files for the path pattern(s) passed into ``cythonize()``
is now an error to more easily detect accidental typos.

* The ``logaddexp`` family of functions in ``numpy.math`` now has correct
declarations.

* In Py2.6/7 and Py3.2, simple Cython memory views could accidentally be
interpreted as non-contiguous by CPython, which could trigger a CPython
bug when copying data from them, thus leading to data corruption.
See CPython issues 12834 and 23349.

Other changes
-------------

* Preliminary support for defining the Cython language with a formal grammar.
To try parsing your files against this grammar, use the --formal_grammar directive.
Experimental.

* ``_`` is no longer considered a cacheable builtin as it could interfere with
gettext.

* Cythonize-computed metadata now cached in the generated C files.

* Several corrections and extensions in numpy, cpython, and libcpp pxd files.

===================

Bugs fixed
----------

* Crash when assigning a C value to both a Python and C target at the same time.

* Automatic coercion from C++ strings to ``str`` generated incomplete code that
failed to compile.

* Declaring a constructor in a C++ child class erroneously required a default
constructor declaration in the super class.

* ``resize_smart()`` in ``cpython.array`` was broken.

* Functions in ``libcpp.cast`` are now declared as ``nogil``.

* Some missing C-API declarations were added.

* Py3 main code in embedding program code was lacking casts.

* Exception related to distutils "Distribution" class type in pyximport under
latest CPython 2.7 and 3.4 releases when setuptools is being imported later.

===================

Features added
--------------

* New ``cythonize`` option ``-a`` to generate the annotated HTML source view.

* Missing C-API declarations in ``cpython.unicode`` were added.

* Passing ``language='c++'`` into cythonize() globally enables C++ mode for
all modules that were not passed as Extension objects (i.e. only source
files and file patterns).

* ``Py_hash_t`` is a known type (used in CPython for hash values).

* ``PySlice_*()`` C-API functions are available from the ``cpython.slice``
module.

* Allow arrays of C++ classes.

Bugs fixed
----------

* Reference leak for non-simple Python expressions in boolean and/or expressions.

* To fix a name collision and to reflect availability on host platforms,
standard C declarations [ clock(), time(), struct tm and tm* functions ]
were moved from posix/time.pxd to a new libc/time.pxd. Patch by Charles
Blake.

* Rerunning unmodified modules in IPython's cython support failed.
Patch by Matthias Bussonier.

* Casting C++ ``std::string`` to Python byte strings failed when
auto-decoding was enabled.

* Fatal exceptions in global module init code could lead to crashes
if the already created module was used later on (e.g. through a
stale reference in sys.modules or elsewhere).

* ``cythonize.py`` script was not installed on MS-Windows.

Other changes
-------------

* Compilation no longer fails hard when unknown compilation options are
passed. Instead, it raises a warning and ignores them (as it did silently
before 0.21). This will be changed back to an error in a future release.

=================

Features added
--------------

* C (cdef) functions allow inner Python functions.

* Enums can now be declared as cpdef to export their values to
the module's Python namespace. Cpdef enums in pxd files export
their values to their own module, iff it exists.

* Allow staticmethod decorator to declare static cdef methods.
This is especially useful for declaring "constructors" for
cdef classes that can take non-Python arguments.

* Taking a ``char*`` from a temporary Python string object is safer
in more cases and can be done inside of non-trivial expressions,
including arguments of a function call. A compile time error
is raised only when such a pointer is assigned to a variable and
would thus exceed the lifetime of the string itself.

* Generators have new properties ``__name__`` and ``__qualname__``
that provide the plain/qualified name of the generator function
(following CPython 3.5). See https://bugs.python.org/issue21205

* The ``inline`` function modifier is available as a decorator
``cython.inline`` in pure mode.

* When cygdb is run in a virtualenv, it enables the same virtualenv
inside of the debugger. Patch by Marc Abramowitz.

* PEP 465: dedicated infix operator for matrix multiplication (A B).

* HTML output of annotated code uses Pygments for code highlighting
and generally received a major overhaul by Matthias Bussonier.

* IPython magic support is now available directly from Cython with
the command "%load_ext cython". Cython code can directly be
executed in a cell when marked with "%%cython". Code analysis
is available with "%%cython -a". Patch by Martín Gaitán.

* Simple support for declaring Python object types in Python signature
annotations. Currently requires setting the compiler directive
``annotation_typing=True``.

* New directive ``use_switch`` (defaults to True) to optionally disable
the optimization of chained if statement to C switch statements.

* Defines dynamic_cast et al. in ``libcpp.cast`` and C++ heap data
structure operations in ``libcpp.algorithm``.

* Shipped header declarations in ``posix.*`` were extended to cover
more of the POSIX API. Patches by Lars Buitinck and Mark Peek.

Optimizations
-------------

* Simple calls to C implemented Python functions/methods are faster.
This also speeds up many operations on builtins that Cython cannot
otherwise optimise.

* The "and"/"or" operators try to avoid unnecessary coercions of their
arguments. They now evaluate the truth value of each argument
independently and only coerce the final result of the whole expression
to the target type (e.g. the type on the left side of an assignment).
This also avoids reference counting overhead for Python values during
evaluation and generally improves the code flow in the generated C code.

* The Python expression "2 ** N" is optimised into bit shifting.
See https://bugs.python.org/issue21420

* Cascaded assignments (a = b = ...) try to minimise the number of
type coercions.

* Calls to ``slice()`` are translated to a straight C-API call.

Bugs fixed
----------

* Crash when assigning memory views from ternary conditional expressions.

* Nested C++ templates could lead to unseparated ">>" characters being
generated into the C++ declarations, which older C++ compilers could
not parse.

* Sending SIGINT (Ctrl-C) during parallel cythonize() builds could
hang the child processes.

* No longer ignore local setup.cfg files for distutils in pyximport.
Patch by Martin Teichmann.

* Taking a ``char*`` from an indexed Python string generated unsafe
reference counting code.

* Set literals now create all of their items before trying to add them
to the set, following the behaviour in CPython. This makes a
difference in the rare case that the item creation has side effects
and some items are not hashable (or if hashing them has side effects,
too).

* Cython no longer generates the cross product of C functions for code
that uses memory views of fused types in function signatures (e.g.
``cdef func(floating[:] a, floating[:] b)``). This is considered the
expected behaviour by most users and was previously inconsistent with
other structured types like C arrays. Code that really wants all type
combinations can create the same fused memoryview type under different
names and use those in the signature to make it clear which types are
independent.

* Names that were unknown at compile time were looked up as builtins at
runtime but not as global module names. Trying both lookups helps with
globals() manipulation.

* Fixed stl container conversion for typedef element types.

* ``obj.pop(x)`` truncated large C integer values of x to ``Py_ssize_t``.

* ``__init__.pyc`` is recognised as marking a package directory
(in addition to .py, .pyx and .pxd).

* Syntax highlighting in ``cython-mode.el`` for Emacs no longer
incorrectly highlights keywords found as part of longer names.

* Correctly handle ``from cython.submodule cimport name``.

* Fix infinite recursion when using super with cpdef methods.

* No-args ``dir()`` was not guaranteed to return a sorted list.

Other changes
-------------

* The header line in the generated C files no longer contains the
timestamp but only the Cython version that wrote it. This was
changed to make builds more reproducible.

* Removed support for CPython 2.4, 2.5 and 3.1.

* The licensing implications on the generated code were clarified
to avoid legal constraints for users.

===================

Features added
--------------

* Some optimisations for set/frozenset instantiation.

* Support for C++ unordered_set and unordered_map.

Bugs fixed
----------

* Access to attributes of optimised builtin methods (e.g.
``[].append.__name__``) could fail to compile.

* Memory leak when extension subtypes add a memory view as attribute
to those of the parent type without having Python object attributes
or a user provided dealloc method.

* Compiler crash on readonly properties in "binding" mode.

* Auto-encoding with ``c_string_encoding=ascii`` failed in Py3.3.

* Crash when subtyping freelist enabled Cython extension types with
Python classes that use ``__slots__``.

* Freelist usage is restricted to CPython to avoid problems with other
Python implementations.

* Memory leak in memory views when copying overlapping, contiguous slices.

* Format checking when requesting non-contiguous buffers from
``cython.array`` objects was accidentally omitted in Py3.

* C++ destructor calls in extension types could fail to compile in clang.

* Buffer format validation failed for sequences of strings in structs.

* Docstrings on extension type attributes in .pxd files were rejected.