At 09:38 PM 6/19/2007 -0400, Phil Jones wrote:
Hi,
I'm Phil Jones, Google Summer of Code student, and I am working on
restructuring the Chandler quick entry code to be able to more
easily add commands and functionality.
There are a couple of different approaches that JeffreyH and I have
been discussing, and I am just looking for some feedback.
Also, if anyone has any good reasons why to use one approach over
the other, please share your thoughts.
Approach 1:
Restructure the quick entry commands code into a parcel and
persistently install into a known location in Chandler.
Extending would create a persistent command parcel and hook into
this quick entry code.
Quick entry would iterate through the commands to determine what
commands are available.
Have a look at the osaf.startup module for an example of how this can
be done, using a custom Item type:
http://chandler.osafoundation.org/docs/0.7/running-code-at-startup.html
In the case of osaf.startup, there aren't any keys to the extensions
(Startup objects), but of course there could be.
Approach 2:
Use a standard dictionary that is in a known location in Chandler to
add new keys with a callback function.
Each of these additions can be performed in a parcel, and work
similar to the first approach but are not stored using the same
persistent mechanism.
If all you need is an ASCII key, and that key doesn't need to contain
any '=' signs, you can also use entry points:
http://peak.telecommunity.com/DevCenter/setuptools#extensible-applications-and-frameworks
http://peak.telecommunity.com/DevCenter/PkgResources#entry-points
This would work by adding entry_points to a plugin's setup.py:
setup(
...
entry_points = {'chandler.quick_entry': ['xyz =
some.module:some_callback']}
)
An individual plugin (or the main Chandler setup.py) can list as many
keys as it wants to support.
Then, the lookup code can simply use something like:
for ep in pkg_resources.iter_entry_points('chandler.quick_entry', key):
callback = ep.load()
# do something with callback here
break # only call the first callback for this key
else:
# no callback found
I would recommend that you either use this approach, or the approach
of defining a specialized Item class (ala osaf.startup.Startup),
rather than creating a special dictionary.
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