plone.z3cform 0.5.8

plone.z3cform is a library that allows use of z3c.form with Zope 2 and the CMF.

plone.z3cform is a library that allows use of z3c.form with Zope 2 and the CMF.

Quick start

A quick example:

>>> from zope import interface, schema
>>> from z3c.form import form, field, button
>>> from plone.z3cform.layout import wrap_form

>>> class MySchema(interface.Interface):
...     age = schema.Int(title=u"Age")

>>> class MyForm(form.Form):
...     fields = field.Fields(MySchema)
...     ignoreContext = True # don't use context to get widget data
...     label = u"Please enter your age"
...
...     @button.buttonAndHandler(u'Apply')
...     def handleApply(self, action):
...         data, errors = self.extractData()
...         print data['age'] # ... or do stuff

>>> MyView = wrap_form(MyForm)

Then, register MyView as a browser:page.

The wrap_form function returns a browser view that embeds your form in a CMF layout template. See the layout module for details.

For more examples, please refer to the z3c.form docs and to this how-to.

Crud

This module gives you an abstract base class to make CRUD forms with. These forms give you by default a tabular view of the objects, where attributes of the object can be edited in-place. Please refer to the ICrudForm interface for more details.

>>> from plone.z3cform.crud import crud

Setup

>>> from plone.z3cform.tests import setup_defaults
>>> setup_defaults()

A simple form

First, let’s define an interface and a class to play with:

>>> from zope import interface, schema
>>> class IPerson(interface.Interface) :
...     name = schema.TextLine()
...     age = schema.Int()

>>> class Person(object):
...     interface.implements(IPerson)
...     def __init__(self, name=None, age=None):
...         self.name, self.age = name, age
...     def __repr__(self):
...         return "<Person with name=%r, age=%r>" % (self.name, self.age)

For this test, we take the the name of our persons as keys in our storage:

>>> storage = {'Peter': Person(u'Peter', 16),
...            'Martha': Person(u'Martha', 32)}

Our simple form looks like this:

>>> class MyForm(crud.CrudForm):
...     update_schema = IPerson
...
...     def get_items(self):
...         return sorted(storage.items(), key=lambda x: x[1].name)
...
...     def add(self, data):
...         person = Person(**data)
...         storage[str(person.name)] = person
...         return person
...
...     def remove(self, (id, item)):
...         del storage[id]

This is all that we need to render a combined edit add form containing all our items:

>>> from z3c.form.testing import TestRequest
>>> print MyForm(None, TestRequest())() \
... # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
<div class="crud-form">...Martha...Peter...</div>

Editing items with our form

Before we start with editing objects, let’s log all events that the form fires for us:

>>> from zope.lifecycleevent.interfaces import IObjectModifiedEvent
>>> from plone.z3cform.tests import create_eventlog
>>> log = create_eventlog(IObjectModifiedEvent)

>>> request = TestRequest()
>>> request.form['crud-edit.Martha.widgets.select-empty-marker'] = u'1'
>>> request.form['crud-edit.Peter.widgets.select-empty-marker'] = u'1'
>>> request.form['crud-edit.Martha.widgets.name'] = u'Martha'
>>> request.form['crud-edit.Martha.widgets.age'] = u'55'
>>> request.form['crud-edit.Peter.widgets.name'] = u'Franz'
>>> request.form['crud-edit.Peter.widgets.age'] = u'16'
>>> request.form['crud-edit.form.buttons.edit'] = u'Apply changes'
>>> html = MyForm(None, request)()
>>> "Successfully updated" in html
True

Two modified events should have been fired:

>>> event1, event2 = log.pop(), log.pop()
>>> storage['Peter'] in (event1.object, event2.object)
True
>>> storage['Martha'] in (event1.object, event2.object)
True
>>> log
[]

If we don’t make any changes, we’ll get a message that says so:

>>> html = MyForm(None, request)()
>>> "No changes made" in html
True
>>> log
[]

Now that we renamed Peter to Franz, it would be also nice to have Franz use ‘Franz’ as the id in the storage, wouldn’t it?

>>> storage['Peter']
<Person with name=u'Franz', age=16>

We can override the CrudForm’s before_update method to perform a rename whenever the name of a person is changed:

>>> class MyRenamingForm(MyForm):
...     def before_update(self, item, data):
...         if data['name'] != item.name:
...             del storage[item.name]
...             storage[str(data['name'])] = item

Let’s rename Martha to Maria. This will give her another key in our storage:

>>> request.form['crud-edit.Martha.widgets.name'] = u'Maria'
>>> html = MyRenamingForm(None, request)()
>>> "Successfully updated" in html
True
>>> log.pop().object == storage['Maria']
True
>>> log
[]
>>> sorted(storage.keys())
['Maria', 'Peter']

Next, we’ll submit the form for edit, but we’ll make no changes. Instead, we’ll select one time. This shouldn’t do anything, since we clicked the ‘Apply changes’ button:

>>> request.form['crud-edit.Maria.widgets.name'] = u'Maria'
>>> request.form['crud-edit.Maria.widgets.age'] = u'55'
>>> request.form['crud-edit.Maria.widgets.select'] = [u'selected']
>>> html = MyRenamingForm(None, request)()
>>> "No changes" in html
True
>>> log
[]

And what if we do have changes and click the checkbox?

>>> request.form['crud-edit.Maria.widgets.age'] = u'50'
>>> html = MyRenamingForm(None, request)()
>>> "Successfully updated" in html
True
>>> log.pop().object == storage['Maria']
True
>>> log
[]

If we omit the name, we’ll get an error:

>>> request.form['crud-edit.Maria.widgets.name'] = u''
>>> html = MyRenamingForm(None, request)()
>>> "There were some errors" in html
True
>>> "Required input is missing" in html
True

We expect an error message in the title cell of Maria:

>>> checkbox_pos = html.index('crud-edit.Maria.widgets.select-empty-marker')
>>> "Required input is missing" in html[checkbox_pos:]
True

Delete an item with our form

We can delete an item by selecting the item we want to delete and clicking the “Delete” button:

>>> request = TestRequest()
>>> request.form['crud-edit.Peter.widgets.select'] = ['selected']
>>> request.form['crud-edit.form.buttons.delete'] = u'Delete'
>>> html = MyForm(None, request)()
>>> "Successfully deleted items" in html
True
>>> 'Franz' in html
False
>>> storage
{'Maria': <Person with name=u'Maria', age=50>}

Add an item with our form

>>> from zope.lifecycleevent.interfaces import IObjectCreatedEvent
>>> from plone.z3cform.tests import create_eventlog
>>> log = create_eventlog(IObjectCreatedEvent)

>>> request = TestRequest()
>>> request.form['crud-add.form.widgets.name'] = u'Daniel'
>>> request.form['crud-add.form.widgets.age'] = u'28'
>>> request.form['crud-add.form.buttons.add'] = u'Add'
>>> html = MyForm(None, request)()
>>> "Item added successfully" in html
True

Added items should show up right away:

>>> "Daniel" in html
True

>>> storage['Daniel']
<Person with name=u'Daniel', age=28>
>>> log.pop().object == storage['Daniel']
True
>>> log
[]

What if we try to add “Daniel” twice? Our current implementation of the add form will simply overwrite the data:

>>> save_daniel = storage['Daniel']
>>> html = MyForm(None, request)()
>>> "Item added successfully" in html
True
>>> save_daniel is storage['Daniel']
False
>>> log.pop().object is storage['Daniel']
True

Let’s implement a class that prevents this:

>>> class MyCarefulForm(MyForm):
...     def add(self, data):
...         name = data['name']
...         if name not in storage:
...             return super(MyCarefulForm, self).add(data)
...         else:
...             raise schema.ValidationError(
...                 u"There's already an item with the name '%s'" % name)

>>> save_daniel = storage['Daniel']
>>> html = MyCarefulForm(None, request)()
>>> "Item added successfully" in html
False
>>> "There's already an item with the name 'Daniel'" in html
True
>>> save_daniel is storage['Daniel']
True
>>> len(log) == 0
True

Render some of the fields in view mode

We can implement in our form a view_schema attribute, which will then be used to view information in our form’s table. Let’s say we wanted the name of our persons to be viewable only in the table:

>>> from z3c.form import field
>>> class MyAdvancedForm(MyForm):
...     update_schema = field.Fields(IPerson).select('age')
...     view_schema = field.Fields(IPerson).select('name')
...     add_schema = IPerson

>>> print MyAdvancedForm(None, TestRequest())() \
... # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
<div class="crud-form">...Daniel...Maria...</div>

We can still edit the age of our Persons:

>>> request = TestRequest()
>>> request.form['crud-edit.Maria.widgets.age'] = u'40'
>>> request.form['crud-edit.Daniel.widgets.age'] = u'35'
>>> request.form['crud-edit.form.buttons.edit'] = u'Apply Changes'
>>> html = MyAdvancedForm(None, request)()
>>> "Successfully updated" in html
True

>>> storage['Maria'].age
40
>>> storage['Daniel'].age
35

We can still add a Person using both name and age:

>>> request = TestRequest()
>>> request.form['crud-add.form.widgets.name'] = u'Thomas'
>>> request.form['crud-add.form.widgets.age'] = u'28'
>>> request.form['crud-add.form.buttons.add'] = u'Add'
>>> html = MyAdvancedForm(None, request)()
>>> "Item added successfully" in html
True
>>> len(storage)
3
>>> storage['Thomas']
<Person with name=u'Thomas', age=28>

Our form can also contain links to our items:

>>> class MyAdvancedLinkingForm(MyAdvancedForm):
...     def link(self, item, field):
...         if field == 'name':
...             return 'http://en.wikipedia.org/wiki/%s' % item.name

>>> print MyAdvancedLinkingForm(None, TestRequest())() \
... # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
<div class="crud-form">...
...<a href="http://en.wikipedia.org/wiki/Daniel"...
...<a href="http://en.wikipedia.org/wiki/Maria"...
...<a href="http://en.wikipedia.org/wiki/Thomas"...
</div>

What if we wanted the name to be both used for linking to the item and for edit? We can just include the title field twice:

>>> class MyAdvancedLinkingForm(MyAdvancedLinkingForm):
...     update_schema = IPerson
...     view_schema = field.Fields(IPerson).select('name')
...     add_schema = IPerson

>>> print MyAdvancedLinkingForm(None, TestRequest())() \
... # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
<div class="crud-form">...
...<a href="http://en.wikipedia.org/wiki/Thomas"...Thomas...</a>...
</div>

We can now change Thomas’s name and see the change reflected in the Wikipedia link immediately:

>>> request = TestRequest()
>>> for name in 'Daniel', 'Maria', 'Thomas':
...     request.form['crud-edit.%s.widgets.name' % name] = unicode(storage[name].name)
...     request.form['crud-edit.%s.widgets.age' % name] = unicode(storage[name].age)
>>> request.form['crud-edit.Thomas.widgets.name'] = u'Dracula'
>>> request.form['crud-edit.form.buttons.edit'] = u'Apply Changes'

>>> print MyAdvancedLinkingForm(None, request)() \
... # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
<div class="crud-form">...
...<a href="http://en.wikipedia.org/wiki/Dracula"...Dracula...</a>...
</div>
>>> storage['Thomas'].name = u'Thomas'

Don’t render one part

What if we wanted our form to display only one part, that is, only the add or the edit form. Our CrudForm can implement editform_factory and addform_factory to override one or both forms. Seeting one of these to crud.NullForm will make them disappear:

>>> class OnlyEditForm(MyForm):
...     addform_factory = crud.NullForm
>>> html = OnlyEditForm(None, TestRequest())()
>>> 'Edit' in html, 'Add' in html
(True, False)

>>> class OnlyAddForm(MyForm):
...     editform_factory = crud.NullForm
>>> html = OnlyAddForm(None, TestRequest())()
>>> 'Edit' in html, 'Add' in html
(False, True)

Render only in view, and define own actions

Sometimes you want to present a list of items, possibly in view mode only, and have the user select one or more of the items to perform some action with them. We’ll present a minimal example that does this here.

We can simply leave the update_schema class attribute out (it defaults to None). Furthermore, we’ll need to override the ediform_factory with our custom version that provides other buttons than the ‘edit’ and ‘delete’ ones:

>>> from pprint import pprint
>>> from z3c.form import button

>>> class MyEditForm(crud.EditForm):
...     @button.buttonAndHandler(u'Capitalize', name='capitalize')
...     def handle_capitalize(self, action):
...         self.status = u"Please select items to capitalize first."
...         selected = self.selected_items()
...         if selected:
...             self.status = u"Capitalized items"
...             for id, item in selected:
...                 item.name = item.name.upper()

>>> class MyCustomForm(crud.CrudForm):
...     view_schema = IPerson
...     editform_factory = MyEditForm
...     addform_factory = crud.NullForm     # We don't want an add part.
...
...     def get_items(self):
...         return sorted(storage.items(), key=lambda x: x[1].name)

>>> request = TestRequest()
>>> html = MyCustomForm(None, TestRequest())()
>>> "Delete" in html, "Apply changes" in html, "Capitalize" in html
(False, False, True)
>>> pprint(storage)
{'Daniel': <Person with name=u'Daniel', age=35>,
 'Maria': <Person with name=u'Maria', age=40>,
 'Thomas': <Person with name=u'Thomas', age=28>}

>>> request.form['crud-edit.Thomas.widgets.select'] = ['selected']
>>> request.form['crud-edit.form.buttons.capitalize'] = u'Capitalize'
>>> html = MyCustomForm(None, request)()
>>> "Capitalized items" in html
True
>>> pprint(storage)
{'Daniel': <Person with name=u'Daniel', age=35>,
 'Maria': <Person with name=u'Maria', age=40>,
 'Thomas': <Person with name=u'THOMAS', age=28>}

We cannot use any of the other buttons:

>>> del request.form['crud-edit.form.buttons.capitalize']
>>> request.form['crud-edit.form.buttons.delete'] = u'Delete'
>>> html = MyCustomForm(None, request)()
>>> "Successfully deleted items" in html
False
>>> 'Thomas' in storage
True

Customizing sub forms

The EditForm class allows you to specify an editsubform_factory-a classs inherits from EditSubForm. This allows you to say, override the crud-row.pt page template and customize the look of the fields.

>>> import zope.schema
>>> class MyCustomEditSubForm(crud.EditSubForm):
...
...     def _select_field(self):
...         """I want to customize the field that it comes with..."""
...         select_field = field.Field(
...         zope.schema.TextLine(__name__='select',
...                              required=False,
...                              title=u'select'))
...         return select_field

>>> class MyCustomEditForm(MyEditForm):
...     editsubform_factory = MyCustomEditSubForm

>>> class MyCustomFormWithCustomSubForm(MyCustomForm):
...     editform_factory = MyCustomEditForm

>>> request = TestRequest()
>>> html = MyCustomFormWithCustomSubForm(None, TestRequest())()

Still uses same form as before

>>> "Delete" in html, "Apply changes" in html, "Capitalize" in html
(False, False, True)

Just changes the widget used for selecting…

>>> 'type="checkbox"' in html
False

Using batching

The CrudForm base class supports batching. When setting the batch_size attribute to a value greater than 0, we’ll only get as many items displayed per page.

>>> class MyBatchingForm(MyForm):
...     batch_size = 2
>>> request = TestRequest()
>>> html = MyBatchingForm(None, request)()
>>> "Daniel" in html, "Maria" in html
(True, True)
>>> "THOMAS" in html
False

>>> request.form['crud-edit.form.page'] = '1'
>>> html = MyBatchingForm(None, request)()
>>> "Daniel" in html, "Maria" in html
(False, False)
>>> "THOMAS" in html
True

Let’s change Thomas’ age on the second page:

>>> request.form['crud-edit.Thomas.widgets.name'] = u'Thomas'
>>> request.form['crud-edit.Thomas.widgets.age'] = '911'
>>> request.form['crud-edit.form.buttons.edit'] = u'Apply changes'
>>> html = MyBatchingForm(None, request)()
>>> "Successfully updated" in html
True
>>> "911" in html
True

Fieldsets and extensible forms

The fieldsets package provides support for groups/fieldsets and other modifications via “extender” adapters. The idea is that a third party component can modify the fields in the form and the way that they are grouped and ordered.

This support relies on a mixin class, which is itself a subclass of z3c.form’s GroupForm.

>>> from plone.z3cform.fieldsets import group, extensible

To use this, you have to mix it into another form as the first base class:

>>> from zope.annotation import IAttributeAnnotatable
>>> from z3c.form import form, field, tests, group
>>> from zope.interface import Interface, implements
>>> from zope import schema

>>> class ITest(Interface):
...     title = schema.TextLine(title=u"Title")

>>> class Test(object):
...     implements(ITest, IAttributeAnnotatable)
...     title = u""

>>> class TestForm(extensible.ExtensibleForm, form.Form):
...     fields = field.Fields(ITest)

Here, note the order of the base classes. Also note that we use an ordinary set of fields. This known as the default fieldset.

This form should work as-is, i.e. we can update it:

>>> from z3c.form.testing import TestRequest

>>> request = TestRequest()
>>> context = Test()

>>> form = TestForm(context, request)
>>> form.update()
>>> _ = form.render()

Now let’s register an adapter that adds two new fields - one in the default fieldset as the first field, and one in a new group. To do this, we only need to register a named multi-adapter. However, we can use a convenience base class to make it easier to manipulate the fields of the form.

>>> from plone.z3cform.fieldsets.interfaces import IFormExtender
>>> from zope.component import adapts, provideAdapter

>>> class IExtraBehavior(Interface):
...     foo = schema.TextLine(title=u"Foo")
...     bar = schema.TextLine(title=u"Bar")
...     baz = schema.TextLine(title=u"Baz")
...     fub = schema.TextLine(title=u"Fub")

One plausible implementation is to use an annotation to store this data.

>>> from zope.annotation import factory
>>> from zope.annotation.attribute import AttributeAnnotations
>>> from persistent import Persistent
>>> class ExtraBehavior(Persistent):
...     implements(IExtraBehavior)
...     adapts(Test)
...
...     foo = u""
...     bar = u""
...     baz = u""
...     fub = u""

>>> ExtraBehavior = factory(ExtraBehavior)
>>> provideAdapter(ExtraBehavior)
>>> provideAdapter(AttributeAnnotations)

We can now write the extender. The base class gives us some helper methods to add, remove and move fields. Here, we do a bit of unnecessary work just to exercise these methods.

>>> class ExtraBehaviorExtender(extensible.FormExtender):
...     adapts(Test, TestRequest, TestForm) # context, request, form
...
...     def __init__(self, context, request, form):
...         self.context = context
...         self.request = request
...         self.form = form
...
...     def update(self):
...         # Add all fields from an interface
...         self.add(IExtraBehavior, prefix="extra")
...
...         # Remove the fub field
...         self.remove('fub', prefix="extra")
...
...         all_fields = field.Fields(IExtraBehavior, prefix="extra")
...
...         # Insert fub again, this time at the top
...         self.add(all_fields.select("fub", prefix="extra"), index=0)
...
...         # Move 'baz' above 'fub'
...         self.move('baz', before='fub', prefix='extra', relative_prefix='extra')
...
...         # Move 'foo' after 'bar' - here we specify prefix manually
...         self.move('foo', after='extra.bar', prefix='extra')
...
...         # Remove 'bar' and re-insert into a new group
...         self.remove('bar', prefix='extra')
...         self.add(all_fields.select('bar', prefix='extra'), group='Second')
...
...         # Move 'baz' after 'bar'. This means it also moves gropu.
...         self.move('extra.baz', after='extra.bar')

>>> provideAdapter(factory=ExtraBehaviorExtender, name=u"test.extender")

With this in place, let’s update the form once again.

>>> form = TestForm(context, request)
>>> form.update()

At this point, we should have a set of default fields that represent the ones set in the adapter.

>>> form.fields.keys()
['extra.fub', 'title', 'extra.foo']

And we should have one group created by the group factory:

>>> form.groups # doctest: +ELLIPSIS
(<plone.z3cform.fieldsets.group.Group object at ...>,)

Note that the created group is of a subtype of the standard z3c.form group, which has got support for a separate label and description as well as a canonical name.

>>> isinstance(form.groups[0], group.Group)
True

This should have the group fields provided by the adapter as well.

>>> form.groups[0].fields.keys()
['extra.bar', 'extra.baz']

Changelog

0.5.8 - 2009-11-24

• Don’t do the rendering if there is a redirection, use the update/render pattern for that. [vincentfretin]

0.5.7 - 2009-11-17

• Fix silly doctests so that they don’t break in Python 2.6 / Zope 2.12 [optilude]

0.5.6 - 2009-09-25

• Added title_required msgid in macros.pt to be the same as plone.app.z3cform because macros.pt from plone.app.z3cform uses plone.z3cform translations. Added French translation and fixed German and Dutch translations for label_required and title_required messages. [vincentfretin]

0.5.5 - 2009-07-26

• Removed explicit <includeOverrides /> call from configure.zcml. This causes race condition type errors in ZCML loading when overrides are included later. [optilude]

0.5.4 - 2009-04-17

• Added monkey patch to fix a bug in z3c.form’s ChoiceTerms on z3c.form 1.9.0. [optilude]

• Fix obvious bugs and dodgy naming in SingleCheckBoxWidget. [optilude]

• Use chameleon-based page templates from five.pt if available. [davisagli]

• Copied the basic textlines widget from z3c.form trunk for use until it is released. [davisagli]

0.5.3 - 2008-12-09

• Add translation marker for batch, update translation files. [thefunny42]

• Handle changed signature for widget extract method in z3c.form > 1.9.0 [davisagli]

• Added wildcard support to the ‘before’ and ‘after’ parameters of the fieldset ‘move’ utility function. [davisagli]

• Fixes for Zope 2.12 compatibility. [davisagli]

• Don’t display an ‘Apply changes’ button if you don’t define an update_schema. [thefunny42]

• Declare xmlnamespace into ‘layout.pt’ and ‘subform.pt’ templates

• Added support for an editsubform_factory for an EditForm so you can override the default behavior for a sub form now.

• Changed css in crud-table.pt for a table to “listing” so that tables now look like plone tables.

• Copy translation files to an english folder, so if your browser negociate to en,nl, you will get english translations instead of dutch ones (like expected). [thefunny42]

• Send an event IAfterWidgetUpdateEvent after updating display widgets manually in a CRUD form. [thefunny42]

0.5.2 - 2008-08-28

• Add a namespace traversal adapter that allows traversal to widgets. This is useful for AJAX calls, for example.

0.5.1 - 2008-08-21

• Add batching to plone.z3cform.crud CrudForm.

• Look up the layout template as an IPageTemplate adapter. This means that it is possible for Plone to provide a “Ploneish” default template for forms that don’t opt into this, without those forms having a direct Plone dependency.

• Default to the titleless form template, since the layout template will provide a title anyway.

• In plone.z3cform.layout, allow labels to be defined per form instance, and not only per form class.

0.5.0 - 2008-07-30

• No longer depend on <3.5 of zope.component.

0.4 - 2008-07-25

• Depend on zope.component<3.5 to avoid TypeError("Missing 'provides' attribute") error.

• Allow ICrudForm.add to raise ValidationError, which allows for displaying a user-friendly error message.

• Make the default layout template CMFDefault- compatible.

0.3 - 2008-07-24

• Moved Plone layout wrapper to plone.app.z3cform.layout. If you were using plone.z3cform.base.FormWrapper to get the Plone layout before, you’ll have to use plone.app.z3cform.layout.FormWrapper instead now. (Also, make sure you include plone.app.z3cform’s ZCML in this case.)

• Move out Plone-specific subpackages to plone.app.z3cform. These are:

  • wysywig: Kupu/Plone integration

  • queryselect: use z3c.formwidget.query with Archetypes

  Clean up testing code and development buildout.cfg to not pull in Plone anymore. [nouri]

• Relicensed under the ZPL 2.1 and moved into the Zope repository. [nouri]

• Add German translation. [saily]

0.2 - 2008-06-20

• Fix usage of NumberDataConverter with zope.i18n >= 3.4 as the previous test setup was partial and did not register all adapters from z3c.form (some of them depends on zope >= 3.4) [gotcha, jfroche]

• More tests [gotcha, jfroche]

0.1 - 2008-05-21

• Provide and register default form and subform templates. These allow forms to be used with the style provided in this package without having to declare form = ViewPageTemplateFile('form.pt').

  This does not hinder you from overriding with your own form attribute like usual. You can also still register a more specialized IPageTemplate for your form.

• Add custom FileUploadDataConverter that converts a Zope 2 FileUpload object to a Zope 3 one before handing it to the original implementation. Also add support for different enctypes. [skatja, nouri]

• Added Archetypes reference selection widget (queryselect) [malthe]

• Moved generic Zope 2 compatibility code for z3c.form and a few goodies from Singing & Dancing into this new package. [nouri]