Re: [Jython-users] ProxyMaker not found?

[Peter B. <bri...@ma...>]

Finn:
> Jythonc attempt to track the flow of name bindings of classes at
> compilation time. Usually this tracking doesn't have to perfect to be
> usefull in real life and so far I haven't been a need like yours.

Here's the reason why I'm interested in the kind of code I posted.
I would like to create a number of classes that share the same
factory (after Gang of Four: "Design Patterns") for creating certain
objects. Ordinarily, one would pass a factory as a parameter when
constructing an object. In this case, however, I would like to
_derive_ a class from another class that's provided by the factory,
so passing the factory as a parameter won't work.

The solution I have in mind works like this: Create an initially
empty module, call it init. The module that determines the concrete
factory imports init and assigns the factory to this module as
a module-global variable, say init.factory. Then the modules that
use this factory import init and work with init.factory (or derive
classes from init.factory.someClass).

I'm not sure whether this is the best possible solution to the problem,
but it is fairly simple and it works. The only drawback I see right now
is that it requires compiler classes in jar files.


> OTOH the example you showed isn't more complicated than jythonc should
> be able to detect that init.cl is java class. Please add bug report
> about it.

I agree that it would be unreasonable to expect jythonc to track the class
of any given variable. I do, however, think that a little more tracking
would be helpful. I've managed to further condense my examples in order
to illustrate the point.

The following example works, even when compiled and packaged without
compiler classes.
---------------------- example1.py ---------------------------
import java

cl=java.lang.Object

class spam(cl):
	pass
--------------------------------------------------------------

The next example does _not_ work without compiler classes.
---------------------- example2.py --------------------------
import java
import init	# any module, can be empty

init.cl=java.lang.Object

class spam(init.cl):
	pass
--------------------------------------------------------------

It appears that jythonc does not track classes across module boundaries,
even though this kind of tracking shouldn't be too difficult in this case.
I think this behavior might qualify as a bug; after all, the two programs
listed above are pretty much the same, so it seems reasonable to expect
them to behave in the same way. Any thoughts?
Best,
	Peter