While I was reading this topic, something just tickled my brain. I
remember that Kevin had mentioned somewhere (screencast probably) about
the posibility of widgets being defined as classes (ref. SQLObject),
rather than with an instantiated object, and a dictionary of fields.
I've been reading about metaclasses recently, and I think it would be
quite possible to create a meta class, that processes a class
definition, and produces something that returns the exact same
structure as currently used in widgets.
What do you think, insane or interesting?
Sean
Michele Cella wrote:
> [EMAIL PROTECTED] wrote:
> > So, at the suggestion of several people on the list today, I figured
> > out the basics of using form widgets. So now my little toy learning
> > application (a wish list) is all widgety. Neat stuff. However, my
> > design for this program relies on the same sort of new/not new status
> > for the list items that the wiki20 tutorial uses to tell the "save"
> > class how to handle the form data. I can't for the life of me figure
> > out how to implement that sort of mechanism using the widgets. I tried
> > a ton of different things, and none of them work. Any guidance would be
> > appreciated.
> >
>
> As Kevin said, if what you need is passing values at display time to
> your widgets that's what you can do.
>
> Let's take the wiki20 Form:
>
> <form action="save" method="post">
> <input type="hidden" name="pagename" py:attrs="value=pagename"/>
> <textarea name="data" py:content="data" rows="10" cols="60"/>
> <input type="submit" name="submit" value="Save"/>
> </form>
>
> In Widgets language :D this becomes something like:
>
> class MyFields(WidgetsList):
> name = HiddenField()
> data = TextArea()
>
> wiki20_form = TableForm(name="page", fields=MyFields(),
> action="save",
> submit_text="Save")
>
> Now if you problem is passing a value to the hidden field, that's what
> you will do from your edit method (for example):
>
> @turbogears.expose(html="wiki20.templates.edit")
> def edit(self, pagename):
> page = Page.byPagename(pagename)
> form_values = dict(name=page.pagename, data=page.data)
> return dict(form=wiki20_form, form_values=form_values)
>
> in your edit.kid page you will need to do this then:
>
> form.display(value=form_values)
>
> One thing to keep in mind, if you're using a CompoundFormField (ATM a
> FieldSet for example) it means you are using a nested field, the value
> you get as input associated to such a field is not a plain value but a
> dictionary containing its field, value pair.
>
> For example:
>
> class NestedFields(WidgetsList):
> one = TextField()
> two = TextField()
>
> class MyFields(WidgetsList):
> name = TextField()
> nested = FieldSet(fields=NestedFields())
>
> myform = TableForm(fields=MyFields(), action="save")
>
> your save method needs to be something like this:
>
> def save(self, name, nested):
>
> The basic rule is that you just expect the parameter you've listed in
> the WidgetsList class that you are passing as fields to the form
> Widget, in this case fields=MyFields() so we use name and nested.
>
> now when you submit such a form that's what you get as input:
>
> name = "myname"
> nested = {"one": "hey", "two": "hello"}
>
> the same rule applies if you need to pass dynamically computed values
> to your form for the first display, so in the previous example (wiki20)
> you don't pass a flat dictionary but a nested dictionary like this one:
>
> form_values = dict(name="michele",
> nested=dict(one="yeah one",
> two="really two"))
>
> finally if you don't need to pass dynamically computed values of you
> just want a field to always have a default value that should be used on
> every first display of your form you can provide it at the widget
> instantiation, for example:
>
> name = TextField(default="Your name here!")
>
> Ciao
> Michele
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