[Zope3-dev] Re: Changes to the schema package

[Garrett Smith]

Philipp von Weitershausen wrote:

> Jim,
> 
>>> Some XXX comments also say, that a value_type/key_type of None should 
>>> not be accepted, but I disagree. I can see that sometimes you do not 
>>> want the value or key of a sequence or dictionary to be of a special 
>>> type. That's when you pass None for value_type/key_type, so the value 
>>> or key will not be validated with a field.
>>
>>
>> That's fine, however, if you don't specify a value type, you can't
>> get a widget for it.  You won't be able to generate a form that
>> has such a field.  Technically, the field type isn't necessary,
>> but, since most people expect to be able to get widgets, it's probably
>> an error if you don't have one.
> 
> 
> Maybe. It'd be great to have some input here to know how other people 
> think.

I'm not using any of these types myself, so I can't offer any solid use 
cases for or against.

Given the relationship between fields and widgets, though, I'm inclined 
to agree with Jim -- can a view (i.e. widget) to such a field really 
succeed without knowing anything about the values/keys?

If you want to store _anything_, can you get by with a field like 
IObject? (I don't know if that already exists.)

Could you give an example of when you'd want value_type/value_key to be 
None and how widgets/forms would handle such a case?

I don't really have a strong opinion on this.

  -- Garrett