Hi Tres, I Am currently using the scheme that I explained in previous postings in an ZClass derived from Object mangager. However, I am facing one small problem. If the ZClass is defined to have *NO* allowable subobjects, adding any meta-types through my code has no effect. If the ZClass is defined to have at least one allowable sub-type, then everything behaves properly. It is my contention that when the first Meta-Type is added through the "subobjects" tag, something else is happening that I am not reproducing in my code, so... 1) Do you think this assumption is correct? 2) What is it that I am missing from my code? thanks for all the help... Josh Zeidner

Josh Zeidner wrote:

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Hmm... possibly I did not explain my needs :

What I need to do is manipulate the attribute of a "folderish" object

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ie. an object that can contain other objects ) that determines what objects are allowed to be contained by my object. I need to do this at instantiation time , *NOT* definition time.

That is what I was targeting -- I guess my implementation wasn't limpidly transparent.

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I seemed to have accomplished this by manipulating the "meta_types" attribute... but is this a valid way to attain this behavior?

That is a more straightforward option than I proposed below -- my code _filters_ the available meta_types based on a tokens/list instance property -- the catch is that you have to replace the standard "contents" view in order to get my code used (I am not really changing what _could_ be added; I merely change the list presented to the user.)

Munging the meta_types attribute is actually an interesting idea -- "normal" Python product objects have the meta_types attribute as a class member; so in fact, you are "hiding" the class member when you assign to the instance attribute. If you ever want to "recover to original," you should be able to just "del self.meta_types" hand have it reappear, presto-changeo.

Glad you found a solution.

Tres. -- ========================================================= Tres Seaver tseaver@palladion.com 713-523-6582 Palladion Software http://www.palladion.com

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