Re: Re: What does Five and Z3 mean for Archetypes?

On Mon, Nov 21, 2005 at 06:59:28PM +0100, Martijn Faassen wrote:
| >Thats great. I'm very interested in hearing what you have to say about
| >it.
| 
| Well, I gave a summary just now. :) Are your usecases for marshalling 
| broader than just export/import? Basically as soon as an 'export' to a 
| potentially untrusted system happens, that should not have all the 
| information in the system, you need to start worrying about which 
| version of which objects you export.

How do you solve that problem in Silva?

| [making widgets that work both in AT as well as in Z3]
| >| Hm, making widgets that work for both sounds like a challenge to me. The 
| >| alternative route would be to try to keep AT as it is intact, but allow 
| >| it to search Zope 3-style widgets and work with them too. Not sure 
| >| whether that's any easier a route to follow, but it would keep the new 
| >| widget clean of code necessary to work with Archetypes in particular.
| >
| >It's actually not that hard, but the z3 widgets would have to 'adapt'
| >the AT fields to the the interface for a z3 field.
| 
| If I understand you correctly, that would be the other way around; using 
| AT widgets within Zope 3.

Nope, its exactly as I said. Unless you are thinking about using z3
*schemas* with AT there's no way to use Z3 widgets with AT fields
unless we adapt the AT fields to Z3 field interface (IField?).

| That's not my preferred path -- it'd prefer 
| extending the library of Zope 3 widgets directly, and allowing AT to use 
| those. I understand that one of the problems with AT widgets is that 
| they're rather complicated, and hopefully by this process we can 
| "refine" them.

They are not 'complicated', just 'too flexible' :) The gross of it is
in Archetypes/skins/archetypes/widgets/field.pt That file has 3 macros
that wrap all the other widget macros. The other nasty part is the
'generator' (generator product), which basically resolves a path to a
macro and injects some local variables into the page template
namespace.

This is more or less what happens:

 - Get a AT field
 - Get the field's Widget
 - Get the widget 'macro' attribute and find a page template by
   simple traversal
 - Find a macro matching the 'mode' parameter
 - Inject 'field', 'widget', 'accessor', 'instance', 'mode' and
   'field_name' in the page template local namespace (equivalent to a
   tal:define)
 - Return the macro

Then basically the forms do a metal:use-macro with what was
returned.

*I* think this last part should be changed to a simple call, eg:
tal:replace="widget", then we can return a Z3 widget and have it be
rendered just as easily.

| >Should be trivial. Archetypes doesn't expect much from a widget other
| >than providing a macro and a method to extract it's own value from the
| >request.
| 
| This is good. Of course Zope 3 doesn't have a macro per widget. :)

That's why I made the suggestion just above.

| >| b) port over Archetypes widgets to Zope 3 style
| >|
| >| then that would hopefully eventually benefit both Archetypes and Zope 3 
| >| equally. I don't know how hard a) is though, and I don't know whether 
| >| Zope 3 is still missing facilities to accomplish b)... I also imagine 
| >| that right now many widgets in Archetypes rely on various facilities 
| >| that are not there or are called differently in Zope 3.
| >
| >I'm +10 on this.
| 
| Good! I think the next step here would be for someone to try porting an 
| interesting AT widget to Zope 3. From the problems this person will have 
| we will learn what changes, if any, Zope 3 needs, and we can recommend a 
| path to take for the next widget. I think I can contribute to this 
| process, even though the AT side of things will have to come from 
| someone else, so I cannot do it alone.

What would be a intersting AT widget? I think the 'RichWidget' is a
good candidate. It embeds kupu and a upload input box in the same widget.

| On another track we could try adjusting Archetypes so it can work with 
| Zope 3 widgets. This needs an AT expert, and that isn't me.

The path of least resistance is removing the requirement that the
widget returns a macro imho.


-- 
Sidnei da Silva
Enfold Systems, LLC.
http://enfoldsystems.com


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