Re: [Zope-dev] ZPatterns question
Steve Alexander wrote: > > return getattr(container.path.to.somewhere, name) > > That's the simple version, and it won't give the traversed-to object the > correct context most of the time. To do that, I'd need to use an > external method, and use the __of__ method to give the returned object > an appropriate context. However, if all you are doing is saying "does this object have the named attribute? if not, get it from another specialist", and you're using Specialist.getItem() to do the latter part, then the object you want comes ready-wrapped in the appropriate context, courtesy of the Rack that gives it to you! -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] ZPatterns question
Steve Spicklemire wrote: > > CS> 2. Is it planned to provide something like a virtual folder > CS> which acts like a normal object manager but is controlled via > CS> ZPatterns (so actually something like Folder with Customizer > CS> Support just without the "anchor" in ZODB. (would also > CS> require some mechanism asked for in 1.) > > Hmmm... I'm not sure what you're after here. Why not just use > a Specialist? In what sense do you want it to be virtual? > (Are you looking for a dynamic traversal interface that > would allow you to map URLs to objects that are managed by > ZPatterns? Can you give an example?) Reading this just after reading the source to Specialists.py, I had a thought; and tried it out; and it works! :-) You can use SkinScript to define __bobo_traverse__ for a particular kind of DataSkin in a Specialist. For example: WITH SELF COMPUTE __bobo_traverse__=traversal_method Then, define a method in the specialist (or rack) called traversal_method. I used a PythonScript, and gave it the parameter list "REQUEST, name". Make your method return the appropriate object to traverse to from your DataSkin, depending on the name passed. Something like return getattr(container.path.to.somewhere, name) That's the simple version, and it won't give the traversed-to object the correct context most of the time. To do that, I'd need to use an external method, and use the __of__ method to give the returned object an appropriate context. However, it is a start, and proves that it can be done. Take a look in the __bobo_traverse__ method of Specialists.py (from ZPatterns) for a good algorithm for traversal. The variable _marker is almost always a class attribute initialized to [], to make a unique object, as a sentinel. -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] ZPatterns question
Hi Christian, Well, nobody else answered that I saw... so I'll take a crack at your questions > "CS" == Christian Scholz <[EMAIL PROTECTED]> writes: CS> Hi there! CS> Finally I managed to get a basic understanding of how to do CS> things with ZPatterns ;-) So seems quite cool :) (and CS> hopefully I find some time to write some basic howto about it) CS> But I have some little questions: CS> 1. Is it possible to retrieve the set of known IDs from a CS> specialist? Or would I need to add my own method to it which CS> does this (and change it accordingly if I switch to another CS> storage method)? If you store persistently you can use the Rack's method: "defaultRack.getPersistentItemIDs()" but a couple of notes: 1) this returns a BTree object, not a simple list, so you can't iterate through it in DTML. You'll need to copy it to a simple list for that.. and 2) If you change to a different storage you'll need to create your own method (ZSQL Method?). What I've found is that if you have a large number of objects you'll either want to query a Catalog, or an SQL database to get Ids that match some criteria that limit the number of hits to something that makes sense to display in a browser. CS> 2. Is it planned to provide something like a virtual folder CS> which acts like a normal object manager but is controlled via CS> ZPatterns (so actually something like Folder with Customizer CS> Support just without the "anchor" in ZODB. (would also CS> require some mechanism asked for in 1.) Hmmm... I'm not sure what you're after here. Why not just use a Specialist? In what sense do you want it to be virtual? (Are you looking for a dynamic traversal interface that would allow you to map URLs to objects that are managed by ZPatterns? Can you give an example?) CS> 3. Is it possible to use ZPatterns also without some exta CS> ZClass defined in a Product? At least if I don't need methods CS> for my objects but simple want to define the attribute they CS> know. Would be nice as I could then hold everything together CS> in one place (the specialist that is) without requiring to CS> install something also in the Products folder of the Control CS> Panel. I believe you need to either create a Python subclass, or a ZClass subclass of DataSkin. "Raw" DataSkins don't have the right permissions to allow for TTW access. If you're creating a 'product' anyway... just make a 'dummy' class that you can use for storage. CS> That's it for now, I will keep experimenting then.. :) Good Luck! -steve CS> cheers, Christian CS> -- Christian Scholz MrTopf@IRC COM.lounge CS> http://comlounge.net/ communication & design [EMAIL PROTECTED] CS> ___ Zope-Dev CS> maillist - [EMAIL PROTECTED] CS> http://lists.zope.org/mailman/listinfo/zope-dev ** No cross CS> posts or HTML encoding! ** (Related lists - CS> http://lists.zope.org/mailman/listinfo/zope-announce CS> http://lists.zope.org/mailman/listinfo/zope ) ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
[Zope-dev] ZPatterns example update....
Hi Folks, The Dumb ZPatterns example is updated. Now there is some more realistic object referencing going on, borrowing of code snippets between Specialists and suchlike. There is also more in the way of reasonable documentation, though everything is in flux, and it still doesn't resemble a truly completed product. I just feel the need to get things finished enough that I can stop thinking about them for a while. ;-) In particular there the ToDos now hold references to Doer and Deliverable, and no 'lists' are maintained. One thing I need to do is to have these references automatically 'fixed' when a 'referred to' entity is removed or modified in such a way that the link should be broken that's for the next version. If I'm not careful.. it won't be a 'simple' example anymore. There's got to be a line here somewhere (in the sand?). take care, -steve ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
