[Zope3-dev] Re: Grok sprint 2 reports

Fri Apr 20 11:29:16 EDT 2007

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Tres Seaver wrote:
> Rocky Burt wrote:
>> On Wed, 2007-10-01 at 11:09 -0500, Tres Seaver wrote:
>>> While I am vehemently opposed to code generation per se, one alternative
>>> which I think is important is to generate stuff *at runtime* from
>>> artifacts which are more understandable to business users than Python
>>> code.  E.g., they might specify schema in a spreadsheet, an HTML form,
>>> or a UML diagram, which we then use to create a schema interface (my
>>> 'userschema' package[1] does this already for the first two).
>> Not sure which mailing list my questions belong on but for the time
>> being I'll ask them here (any list subscribers feel free to tell me to
>> take this discussion offline).
> 
>> This userschema package looks very cool and it's nice to see all the
>> cool ways you can produce schema's from user contributed data (ie csv,
>> html).  But I'm curious to know what sort of use cases you have for the
>> end-result schema's ... simple formlib form generation? content type +
>> edit form (via formlib) generation?
> 
> Obviously generated UI is the main use-case;  I have some notions about
> making it easier to use schema stuff from within "custom" UI, but they
> aren't fleshed out yet.
> 
> I do have a notion of allowing the template which *specifies* the schema
> to be used to *render* its fields, but haven't got that part working
> yet.  Chris McDonough and I have talked about using a meld3-based
> approach to that, as well.

(Sorry to follow up to myself, and so late).

While at the BBQ sprint last month, Philipp and I worked on a prototype
for this last idea.  Although it isn't cleaned up yet for a release, the
essence of it is to put the 'index' and 'edit' templates (hand-rolled,
of course) into the appropriate subdirectory, and then use a new grok
directive to get the class and all its views wired up.  E.g.::

 $ cat simple_templates/index.pt
 <html>
 <body>

 <div tal:content="structure context/body | nothing">
 BODY
 </div>

 </body>
 </html>

 $ cat simple_templates/edit.pt
 <html>
 <body>
 <form name="simple_edit" action="." method="POST">

 <fieldset id="body_fs">
  <legend>Simple Body</legend>
  <textarea id="doc_body" name="body" rows="20" cols="80"
            tal:attributes="name view/widget/body/name|default"
            tal:content="view/widgets/body/_getFormValue"></textarea>
 </fieldset>

 <div>
  <input type="submit" name="form.submitted" value=" Save Changes "
         tal:repeat="action view/actions"
         tal:attributes="name action/__name__;
                         value action/label" />
 </div>

 </form>

 </body>
 </html>

 $ cat app.py
 import grok
 import grok_crud
 from zope.formlib import form

 class SimpleApp(grok.Application, grok.Container):
     pass

  class Index(grok.View):
     grok.context(SimpleApp)

 class Simple(grok_crud.Crud):
     grok_crud.directory('simple')

With something like meld3, we could even get rid of the hairy TALES
expressions in the tmeplates, making them purely the domain of the designer.

Tres.
- --
===================================================================
Tres Seaver          +1 540-429-0999          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
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