Hello everyone,<br> as a few knows here, I'm working heavily with PyPy's "stackless" module for my Master degree project to make it more distributed. Since I started to work full time on this project I've encountered a few bugs (mostly related to pickling of tasklets) and missing implementation details in the module. The latest problem I've encountered is to be able to detect when tasklet.kill() is called, within the tasklet being killed. With Stackless CPython, TaskletExit is raised and can be caught but this part wasn't really implemented in PyPy's stackless module. Since the module is implemented on top of coroutines and since coroutine.kill() is called within tasklet.kill(), the exception thrown by the coroutine implementation needs to be caught. Here's the problem:<br>
<br><a href="http://codespeak.net/pypy/dist/pypy/doc/stackless.html#coroutines">http://codespeak.net/pypy/dist/pypy/doc/stackless.html#coroutines</a><br><ul><li><p class="first"><tt class="docutils literal"><span class="pre">coro.kill()</span></tt></p>
<blockquote>
<p>Kill <tt class="docutils literal"><span class="pre">coro</span></tt>
by sending an exception to it. (At the moment, the
exception is not visible to app-level, which means that you cannot
catch it, and that <tt class="docutils literal"><span class="pre">try:</span>
<span class="pre">finally:</span></tt> clauses are not honored. This
will be fixed in the future.)</p></blockquote></li></ul>The exception is not thrown at app level and a coroutine dies silently. Took a look at the code and I've been able to expose a CoroutineExit exception to app level on which I intend implementing TaskletExit correctly. I'm also able to catch the exception as expected but the code is not yet complete. <br>
<br>Right now, I have a question on how to expose correctly the CoroutineExit and TaskletExit exceptions to app level. Here's what I did:<br><br>W_CoroutineExit = _new_exception('CoroutineExit', W_Exception, 'Exit requested...')<br>
<br>class AppCoroutine(Coroutine): # XXX, StacklessFlags):<br><br> def __init__(self, space, state=None):<br> # Some other code here<br> <br> # Exporting new exception to __builtins__ and "exceptions" modules<br>
self.w_CoroutineExit = space.gettypefor(W_CoroutineExit)<br> space.setitem(<br> space.exceptions_module.w_dict, <br> space.new_interned_str('CoroutineExit'), <br>
self.w_CoroutineExit) <br> space.setitem(space.builtin.w_dict, <br> space.new_interned_str('CoroutineExit'), <br> self.w_CoroutineExit)<br><br clear="all">
I talked about this on #pypy (IRC) but people weren't sure about exporting new names to __builtins__. On my side I wanted to make it look as most as possible as how Stackless CPython did it with TaskletExit, which is directly available in __builtins__. This would make code compatible with both Stackless Python and PyPy's stackless module. Also, exporting names this way would only make them appear in __builtins__ when the "_stackless" module is enabled (pypy-c built with --stackless). <br>
<br>What are your opinions about it? (Maciej, I already know about yours! ;)<br><br>Thank you very much,<br><br>Gabriel (WildChild)<br><br>-- <br>Gabriel Lavoie<br><a href="mailto:glavoie@gmail.com">glavoie@gmail.com</a><br>