[PEAK] Laziness, terminology, and the Trellis API

[Sergey Schetinin]

Phillip,

I'm using AddOns a lot, and in fact was using it here as well, but 
that's not the issue. I just think that a similar decorator would be 
generally useful.

P.S. Great libraries, always a pleasure to use and learn about. Thanks a 
lot.

Phillip J. Eby wrote:
> At 03:04 AM 3/14/2008 +0200, Sergey Schetinin wrote:
>> Looks very reasonable to me. One thing that seems to missing is API to 
>> declare non-method observers, one can just create a Cell, but then you 
>> need to get a value once to initialize the dependencies and you still 
>> have to think about keeping a reference. Maybe it's a bad idea but I 
>> keep creating rules from closures, so I created a decorator to make it 
>> easier, maybe it's good enough to include in the core API:
>>
>> from peak.events.trellis import Cell
>>
>> __all__ = ['rule_for']
>>
>> def rule_for(ob):
>>     add = ob.__dict__.setdefault(rule_for, []).append
>>     def deco(m):
>>         cell = Cell(m)
>>         cell.value
>>         add(cell)
>>         return m
>>     return deco
>>
>>
>> To be used like this:
>>
>> ...
>> def track_status(self, status):
>>     @rule_for(status)
>>     def onstatus():
>>         status.set(self.process.status)
> 
> 
> I would just use an AddOn with a rule, myself.  See the AddOns library 
> in the Cheeseshop.
>