A control framework for wxPython, thoughts...

Mike_C_Fletcher2 · March 6, 2003, 9:55am

As I'm finishing this particular iteration of wxoo, I'm coming to realise that I need a better system for registering/resolving interfaces and adapters for controls, views and data structures. Something along the lines of an Active-X system, but hopefully usable .

I've been seriously considering ripping the interface and registry code out of zope3 and using that. It appears to do much of what I want (including registering interfaces for non-extensible types) with regard to interfaces and allowing externally-applied adapters. It is, however, still alpha code, and I'd prefer to go with something a little more stable.

Anyone have a better suggestion for something that would provide some significant sub-set of these features:

    * Declare and test conformance to interfaces
          o Both property and method members
          o Allow distinct class and instance declarations
    * Query for an object's implementation of an interface
          o Allow for Adapter objects to be returned to implement the
            interface
          o Allow built-in and non-extendable objects being registered
            as implementing an interface, potentially with an adapter
            class which would implement the interface
          o Allow for both class and instance interfaces

My current code does this stuff in an ad-hoc manner (there's no explicitly defined interfaces, just code in various places that falls back from one possible interface-source to another when it's trying to get an interface for an object), but I'm looking for something that will formalise, clean up, and solidify the interface-definition/resolution process before I get into defining higher-level abstractions. (e.g. sets, ordered sets, sub-sets, trees, collections, and collection-indices).

More concrete ideas of interfaces I'm looking at:

class ITypeCoercian:
    def coerce( cls, value ):
        """Coerce value to an instance of class"""
class ITypeCheck:
    def check( cls, value ):
        """Do a strict check to see if the value is a valid instance of cls"""
class IAllValuesSet:
    def getAllValues( self ):
        """Retrieve a set object with all suitable values for the type"""
class ICommonValuesSet:
    def getCommonValues( self ):
        """Retrieve a set of common values for the type"""
class IWatchable:
class ICallable:
class IPersistable:
class IProvideXContext:
class ISequence:
class IMapping:
class ICollection:
class ICollectionIndex:
...
class IValueEditControl:
    def GetValue( self ):
        """Return the current value of the control"""
    def SetValue( self, value ):
        """Set the current value of the control"""
    generatedEvents = [ ValueChangedEvent ]
class IEditType:
    """Interface declaring type which may be edited by a control"""
    dataTypes = [unicode,str]
class IPreferedSize:
    """Interface declaring prefered size of a control

    i.e. to be used during control resolution to provide
    the best-sized control for a particular location.
    """
...
class IViewContext:
class IViewSelectionSet:
class IViewFocus:
class IViewActionSet:
...

Anyway, suggestions or thoughts appreciated,
Mike

···

_______________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://members.rogers.com/mcfletch/

Niki · March 18, 2003, 12:38pm

Mike C. Fletcher wrote:

As I'm finishing this particular iteration of wxoo, I'm coming to realise that I need a better system for registering/resolving interfaces and adapters for controls, views and data structures. Something along the lines of an Active-X system, but hopefully usable .

I've been seriously considering ripping the interface and registry code out of zope3 and using that. It appears to do much of what I want (including registering interfaces for non-extensible types) with regard to interfaces and allowing externally-applied adapters. It is, however, still alpha code, and I'd prefer to go with something a little more stable.

Anyone have a better suggestion for something that would provide some significant sub-set of these features:

   * Declare and test conformance to interfaces
         o Both property and method members
         o Allow distinct class and instance declarations
   * Query for an object's implementation of an interface
         o Allow for Adapter objects to be returned to implement the
           interface
         o Allow built-in and non-extendable objects being registered
           as implementing an interface, potentially with an adapter
           class which would implement the interface
         o Allow for both class and instance interfaces

More concrete ideas of interfaces I'm looking at:

class ITypeCoercian:
   def coerce( cls, value ):
       """Coerce value to an instance of class"""
...
class IViewContext:
class IViewSelectionSet:
class IViewFocus:
class IViewActionSet:
...

Anyway, suggestions or thoughts appreciated,

PEAK does this. Default for DB stuff byt why not to extend it to GUI.

Niki Spahiev

Mike_C_Fletcher2 · March 18, 2003, 7:38pm

Argh. Wish I'd seen this stuff a lot earlier. Same basic problem domain at the Python/app level, similar approach (both use ZODB's persistence, both use Zope's interface mechanisms AFAICS). Sigh.

Thanks for the pointer,
Mike

Niki Spahiev wrote:
...

PEAK does this. Default for DB stuff byt why not to extend it to GUI.

Niki Spahiev

...

···

_______________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://members.rogers.com/mcfletch/