Author: Rami Chowdhury <[email protected]>
Branch: improve-docs
Changeset: r66435:0ddc7560abce
Date: 2013-08-28 22:06 +0100
http://bitbucket.org/pypy/pypy/changeset/0ddc7560abce/
Log: Add Sphinx tags to `objspace-proxies`, fix `objspace` tags
diff --git a/pypy/doc/objspace-proxies.rst b/pypy/doc/objspace-proxies.rst
--- a/pypy/doc/objspace-proxies.rst
+++ b/pypy/doc/objspace-proxies.rst
@@ -6,8 +6,7 @@
Thanks to the :doc:`Object Space <objspace>` architecture, any feature that is
based on proxying, extending, changing or otherwise controlling the
-behavior of all objects in a running program is easy to implement on
-top of PyPy.
+behavior of objects in a running program is easy to implement on top of PyPy.
Here is what we have implemented so far, in historical order:
@@ -26,11 +25,11 @@
-------------------
PyPy's Transparent Proxies allow routing of operations on objects
-to a callable. Application level code can customize objects without
+to a callable. Application-level code can customize objects without
interfering with the type system - ``type(proxied_list) is list`` holds true
-when 'proxied_list' is a proxied built-in list - while
+when :py:obj:`proxied_list` is a proxied built-in :py:class:`list` - while
giving you full control on all operations that are performed on the
-``proxied_list``.
+:py:obj:`proxied_list`.
See [D12.1]_ for more context, motivation and usage of transparent proxies.
@@ -38,8 +37,8 @@
Example of the core mechanism
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The following example proxies a list and will
-return ``42`` on any add operation to the list::
+The following example proxies a list and will return ``42`` on any addition
+operations::
$ py.py --objspace-std-withtproxy
>>>> from __pypy__ import tproxy
@@ -59,7 +58,7 @@
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Suppose we want to have a list which stores all operations performed on
-it for later analysis. We can use the small :source:`lib_pypy/tputil.py`
module to help
+it for later analysis. We can use the :source:`lib_pypy/tputil.py` module to
help
with transparently proxying builtin instances::
from tputil import make_proxy
@@ -79,12 +78,12 @@
2
``make_proxy(recorder, obj=[])`` creates a transparent list
-proxy where we can delegate operations to in the ``recorder`` function.
+proxy that allows us to delegate operations to the :py:func:`recorder`
function.
Calling ``type(l)`` does not lead to any operation being executed at all.
-Note that ``append`` shows up as ``__getattribute__`` and that ``type(lst)``
-does not show up at all - the type is the only aspect of the instance which
-the controller cannot change.
+Note that :py:meth:`append` shows up as :py:meth:`__getattribute__` and that
+``type(l)`` does not show up at all - the type is the only aspect of the
instance
+which the proxy controller cannot change.
.. _transparent proxy builtins:
@@ -95,14 +94,16 @@
If you are using the `--objspace-std-withtproxy`_ option
the :doc:`__pypy__ <__pypy__-module>` module provides the following builtins:
-* ``tproxy(type, controller)``: returns a proxy object
- representing the given type and forwarding all operations
- on this type to the controller. On each such operation
- ``controller(opname, *args, **kwargs)`` is invoked.
+.. py:function:: tproxy(type, controller)
-* ``get_tproxy_controller(obj)``: returns the responsible
- controller for a given object. For non-proxied objects
- ``None`` is returned.
+ Returns a proxy object representing the given type and forwarding all
+ operations on this type to the controller. On each operation,
+ ``controller(opname, *args, **kwargs)`` will be called.
+
+.. py:function:: get_tproxy_controller(obj)
+
+ Returns the responsible controller for a given object. For non-proxied
+ objects :py:const:`None` is returned.
.. _--objspace-std-withtproxy: config/objspace.std.withtproxy.html
@@ -114,32 +115,43 @@
The :source:`lib_pypy/tputil.py` module provides:
-* ``make_proxy(controller, type, obj)``: function which
- creates a transparent proxy controlled by the given
- 'controller' callable. The proxy will appear
- as a completely regular instance of the given
- type but all operations on it are send to the
- specified controller - which receives a
- ProxyOperation instance on each such operation.
- A non-specified type will default to type(obj) if
- `obj` was specified.
+.. py:function:: make_proxy(controller, type, obj)
+
+ Creates a transparent proxy controlled by the given :py:obj:`controller`
+ callable. The proxy will appear as a completely regular instance of the
given
+ type, but all operations on it are sent to the specified controller - which
+ receives a :py:class:`ProxyOperation` instance on each operation. If
:py:obj:`type`
+ is not specified, it defaults to ``type(obj)`` if :py:obj:`obj` is specified.
ProxyOperation instances have the following attributes:
- `proxyobj`: the transparent proxy object of this operation.
+ .. py:attribute:: proxyobj
- `opname`: the operation name of this operation
+ The transparent proxy object of this operation.
- `args`: positional arguments for this operation
+ .. py:attribute:: opname
- `kwargs`: keyword arguments for this operation
+ The name of this operation.
- `obj`: (if provided to `make_proxy`): a concrete object
+ .. py:attribute:: args
- If you have specified a concrete object instance `obj`
- to your `make_proxy` invocation, you may call
- ``proxyoperation.delegate()`` to delegate the operation
- to this object instance.
+ Any positional arguments for this operation.
+
+ .. py:attribute:: kwargs
+
+ Any keyword arguments for this operation.
+
+ .. py:attribute:: obj
+
+ (Only if provided to :py:func:`make_proxy`)
+
+ A concrete object.
+
+ .. py:method:: delegate
+
+ If a concrete object instance :py:obj:`obj` was specified in the call to
+ :py:func:`make_proxy`, then :py:meth:`proxyoperation.delegate` can be
called
+ to delegate the operation to the object instance.
Further points of interest
@@ -152,34 +164,33 @@
(think about transparent distribution)
* Access to persistent storage such as a database (imagine an
- SQL object mapper which looks like a real object)
+ SQL object mapper which looks like any other object).
* Access to external data structures, such as other languages, as normal
objects (of course some operations could raise exceptions, but
- since they are purely done on application level, that is not real problem)
+ since operations are executed at the application level, that is not a major
+ problem)
Implementation Notes
~~~~~~~~~~~~~~~~~~~~
-PyPy's standard object space allows to internally have multiple
-implementations of a type and change the implementation at run
-time while application level code consistently sees the exact
-same type and object. Multiple performance optimizations using
-this features are already implemented: see the document
-about :doc:`alternative object implementations <interpreter-optimizations>`.
Transparent
-Proxies use the architecture to provide control back
-to application level code.
+PyPy's standard object space allows us to internally have multiple
+implementations of a type and change the implementation at run-time, while
+application-level code consistently sees the exact same type and object.
+Multiple performance optimizations using these features have already been
+implemented: :doc:`alternative object implementations
<interpreter-optimizations>`.
+Transparent Proxies use this architecture to provide control back to
+application-level code.
Transparent proxies are implemented on top of the :ref:`standard object
-space <standard-object-space>`, in
:source:`pypy/objspace/std/proxy_helpers.py`,
:source:`pypy/objspace/std/proxyobject.py` and
-:source:`pypy/objspace/std/transparent.py`. To use them you will need to pass
a
-`--objspace-std-withtproxy`_ option to ``py.py`` or
-``translate.py``. This registers implementations named
-``W_TransparentXxx`` - which usually correspond to an
-appropriate ``W_XxxObject`` - and includes some interpreter hacks
-for objects that are too close to the interpreter to be
-implemented in the std objspace. The types of objects that can
+space <standard-object-space>`, in
:source:`pypy/objspace/std/proxy_helpers.py`,
+:source:`pypy/objspace/std/proxyobject.py` and
:source:`pypy/objspace/std/transparent.py`.
+To use them you will need to pass a `--objspace-std-withtproxy`_ option to
``pypy``
+or ``translate.py``. This registers implementations named
:py:class:`W_TransparentXxx`
+- which usually correspond to an appropriate :py:class:`W_XxxObject` - and
+includes some interpreter hacks for objects that are too close to the
interpreter
+to be implemented in the standard object space. The types of objects that can
be proxied this way are user created classes & functions,
lists, dicts, exceptions, tracebacks and frames.
diff --git a/pypy/doc/objspace.rst b/pypy/doc/objspace.rst
--- a/pypy/doc/objspace.rst
+++ b/pypy/doc/objspace.rst
@@ -575,7 +575,7 @@
Additionally, slicing ensures that ``5 .__add__(6L)`` correctly returns
:py:exc:`NotImplemented` (because this particular slice does not include
:py:func:`add__Long_Long` and there is no :py:func:`add__Int_Long`), which
leads to
-'`6L.__radd__(5)`` being called, as in CPython.
+``6L.__radd__(5)`` being called, as in CPython.
Object Space proxies
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