[Zope3-dev] Re: Merging schema & interfaces (was: "Sub interface")

[Sidnei da Silva]

On Tue, Mar 02, 2004 at 09:49:53AM -0500, Jim Fulton wrote:
| To deal with constraints on multiple fields, we will add the ability to
| model interface/schema-level invariants/constraints.
| 
| def cityStateZip(contact):
|     pc = lookupPostalCodeFor(contact.city, contact.state)
|     if pc != contact.postal_code:
|        raise InvalidPostalCode(contact)
| 
| class IContact(zope.interface.Interface):
| 
|    postal_code = ...
|    city = ...
|    state = ...
| 
|    invariant(cityStateZip)
| 
| Then, when we modify a contact, we can check individual
| field constraints *and* we can check the interface-level invariants.
| 
| This has been on my unofficial to-do list for some time.
| It just needs a volunteer. :)  (It's not on the official
| to-do list because we haven't actually needed it yet.)

This looks very good to me, and I even feel like volunteering, given
enough directions ;) I can probably find some time for this on our
current project, in the near future.

-- 
Sidnei da Silva <sidnei at awkly.org>
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