clean up userguide/limitations.rst, let it refer to the bug tracker

docs/src/userguide/limitations.rst

@@ -6,70 +6,11 @@
 Limitations
 *************
 
-Unsupported Python Features
-============================
-
-One of our goals is to make Cython as compatible as possible with standard
-Python. This page lists the things that work in Python but not in Cython.
-As Cython matures, the items in this list should go away. 
-
-
-Generators and generator expressions
--------------------------------------
-
-The yield keyword is not yet supported.  This is work in progress.
-
-Since Cython 0.13, some generator expressions are supported when they
-can be transformed into inlined loops in combination with builtins,
-e.g.  ``sum(x*2 for x in seq)``.  As of 0.14, the supported builtins
-are ``list()``, ``set()``, ``dict()``, ``sum()``, ``any()``,
-``all()``, ``sorted()``.
-
-
-Other Current Limitations
-==========================
-
-* The :func:`globals` builtin returns the last Python callers globals, not the current function's locals. This behavior should not be relied upon, as it will probably change in the future. 
-* The :func:`locals` builtin can only be used if all local variables can be converted to Python objects, and returns a dict.
-* Class and function definitions cannot be placed inside control structures.
-
-Semantic differences between Python and Cython
-----------------------------------------------
-
-Behaviour of class scopes
-^^^^^^^^^^^^^^^^^^^^^^^^^
-
-In Python, referring to a method of a class inside the class definition, i.e.
-while the class is being defined, yields a plain function object, but in
-Cython it yields an unbound method [#]_. A consequence of this is that the
-usual idiom for using the :func:`classmethod` and :func:`staticmethod` functions,
-e.g.::
-
-    class Spam:
-
-        def method(cls):
-            ...
-
-        method = classmethod(method)
-
-will not work in Cython. This can be worked around by defining the function
-outside the class, and then assigning the result of ``classmethod`` or
-``staticmethod`` inside the class, i.e.::
-
-    def Spam_method(cls):
-        ...
-
-    class Spam:
-
-        method = classmethod(Spam_method)
-
-This will change in the near future. 
-
-.. rubric:: Footnotes
-
-.. [#] The reason for the different behaviour of class scopes is that
-       Cython-defined Python functions are ``PyCFunction`` objects, not
-       ``PyFunction`` objects, and are not recognised by the machinery that creates a
-       bound or unbound method when a function is extracted from a class. To get
-       around this, Cython wraps each method in an unbound method object itself
-       before storing it in the class's dictionary.
+This page used to list bugs in Cython that made the semantics of
+compiled code differ from that in Python.  Most of the missing
+features have been fixed in Cython 0.15.  The bug tracker has an
+up-to-date `list of remaining compatibility issues`_.  Note that a
+future version 1.0 of Cython is planned to provide full Python
+language compatibility.
+
+.. _`list of remaining compatibility issues`: http://trac.cython.org/cython_trac/query?status=assigned&status=new&status=reopened&component=Python+Semantics&component=Python3+Semantics&order=priority&col=id&col=summary&col=component&col=status&col=type&col=priority&col=milestone