[TransWarp] first experiences with Transwarp

ML lists at net-labs.de
Tue Mar 26 20:05:48 EST 2002

For some reason, this post from Ulrich didn't make it through to the list...

Hi Phillip,

 > I would advise holding off for a bit on digging too deep into the use of
 > Elements and Features, however, as I'm about to redo their API
 > entirely.  After that's done, it should be possible to make some simple
.. <snip>

i watch your progress with Element/Features ... looks promising :)

I have worked on a concept for the GUI with Transwarp .. this is my
way to evaluate Transwarp for our project ..

precondition is that one uses wxWindows and the new XML-Resource-system.

I have come up with a similar system to RecordManager->RecordType:

all Gui-Objects derive from baseclass GUIObject(SEF.Base) that has a class-init
method that finds it Child-Objects (only classes/instances of 
and stores it in newClass.guiObjects.

a <root-class>.setup() method set's up the whole GUI-Object-Tree recursivly.
by invoking <child>.setup(). this is actually needed because i make heavy 
use of
SEF-Bindings that don't exist at __init__  and some wxPython issues.

I created BaseClasses for Window,Panel,Control,Event,Menu,... and some 
Most of them are Services.

a Menu-Specification would look like:
from TW.API import *
from wxPython.wx import *
from EMF.GUI.Menu import MenuBar,Menu,MenuItem
from EMF.GUI.Event import connectEvent

class MainMenu(MenuBar):
  _xmlid = 'menuMain'

  class Console(Menu):
   _xmlid = 'mnuConsole'

   class Save(MenuItem):
    _xmlid = 'mnuConsoleSave'

    OnConsoleSave = connectEvent(EVT_MENU)

   class Exit(MenuItem):
    _xmlid = 'mnuConsoleExit'

    def OnConsoleExitHandler(self,event):
     return 1

    OnConsoleExit = connectEvent(EVT_MENU,func=OnConsoleExitHandler)

- MenuBar,Menu,MenuItem are Services
- _xmlid Attribute allways specifies the XMLID of the Resource
- connectEvent is a specialization of Once that creates an Event-Connector 
to the given
   wxEvent and the EventDispatcher (one can specify a custom func via 
func=<method> param)
- If a GUIObject contains anothers, these are it's child-objects (e.g. 
MenuBar has Menus, these
   have MenuItems ...):

a Panel-Specification would look like:
from TW.API import *
from EMF.GUI.Basic import *
from EMF.GUI import Event
from EMF.GUI.Panel import SplitWindow,Panel
from EMF.GUI.Control import TextControl,TreeControl,Button
from EMF.GUI.Event import connectEvent

class MainPanel(SplitWindow):

  class EventDispatcher(Event.EventDispatcher):
   def _dispatch(self,name,obj,event,category):
    if category in ['Control','Panel']:
     self.log.debug(self,"handling event: %s" % name)
     return 1 # do not dispatch ...

  class TreePanel(Panel):
   _xmlid = 'panelMainTree'

   class treeMain(TreeControl):
    _xmlid = 'treeControl'

    def _setup_control(self):
     ##### this should come from DataLayer
     self.treeRoot = self.WX.AddRoot('someTest')

  class ListPanel(Panel):
   _xmlid = 'panelDialogNBFirst'

   class txtFirst(TextControl):
    _xmlid = 'txtFirst'

   class txtSecond(TextControl):
    _xmlid = 'txtSecond'

   class txtThird(TextControl):
    _xmlid = 'txtThird'

   class btOK(Button):
    _xmlid = 'btOK'

   class btCancel(Button):
    _xmlid = 'btCancel'

- the BaseClasses have an EventLayer mixed in, that provides a standard set of
   pre-connected Events for the Controls/Buttons/Panels
   e.g. ListControl has OnListItemSelected/... predefined.
- I expect an "EventDispatcher" that is a placefull service defined 
somewhere in your
   app, that handles all Events for it's domain or forward it to an 
   up in the Tree.
- There is an ordering problem .. which Panel will be first in 
newClass.__dict__.items() ?
   i will probably use the attribute guiObjects =['TreePanel','ListPanel'] 
to fix this.

a MainWindow example:
from TW.API import *
from EMF.GUI.Basic import *
from EMF.GUI.Window import MainWindow,loadResource

class AppWindow(MainWindow):

  Resources = loadResource('emfgui_wdr.xrc')
  from MyMenu import MainMenu
  from MyPanels import MainPanel
  from EMF.GUI.Event import EventDispatcher

- loadResource is again a specialization of Once that loads the XML-Resource
- Only import all the defined components and a write a
simple Main app:
from TW.API import *
from EMF.GUI.Basic import *
from EMF.GUI.App import App

class TestApp(App):

  from Main import AppWindow

  # replace App._init_app
  def _init_app(self,parent):
   return true

def __init__():
      if __name__=='__main__':
          app = TestApp()


.. that's it .. ;-)

this is quite a bit code for the first example .. but i find it necessary 
to make the
concept a bit clearer.

i have attached a sample output from my logger-module (that i extended a bit to
print out the inheritance-tree of the objects .. somewhat the "url" of the 

after coming that far .. I'ld like to hear your comment.

it is working with latest cvs-checkouts of TW and wxPython-2.3.2 on win and 
linux ..
i can provide the sources of the lib if anyone is interested in this early 
stage ...

i build the framework without use of the (Data)Elements and Features .. 
because as
far as i understand they are provided by the specialists of my Application.
right now there is no connection between the controls and the features of
an Element and i have not yet found a satisfying solution for this problem.

Do you have a hint, how I could "link" the setter/getter - methods of my 
with an Elements-Feature somewhere up in the object-tree: make use of an
"Element" Service that provides the current Element or some better idea??
then you would be able to map the controls-values to the Elements features
and most of standard-typing would be gone :)

what do you think ??

Ulrich Eck
ueck at net-labs.de
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