How to attach new member to instance of sprite in python?

Here is the test cap file:

http://dl.dropbox.com/u/5779181/objspv_access.zip

There are many instances of objA. I try to attach a new member named "_value" on each instance.

for _obj in objA:
    _obj._value = 10
_obj = objA[0]
output.SetText("%d"%(_obj._value))[/code:vvgcwmd3]
And get the error message:
[quote:vvgcwmd3]TypeError: %d format: a number is required, not NoneType

from the last one "output.SetText("%d"%(_obj._value))".
It seems I can not attach new member to each instance.

Another way, 
[code:vvgcwmd3]objA._value = 10
output.SetText("%d"%(objA._value))[/code:vvgcwmd3]
It works. I can attach new member to objA (not objA[0]).

What's different between "objA._value" and "objA[0]._value" in this case?

[quote:2py1z69r]What's different between "objA._value" and "objA[0]._value" in this case?

objA is the class to access objA instances and exists for the duration of the application. objA[0] creates a temporary class to access that instance.

Here is a fix:

Add this code to 'Start of Layout' before you run any other code to be able to attach new members to instances.

class _instance_values:
	pass

_Instances._vals_=dict()
for _ot in _Instances.__dict__.items():
	if _ot[0][0]=='_':
		continue
	_ot[1]._oldgetattr=_ot[1].__getattr__
	def mygetattr(this, attr):
		objkey=this.__dict__['__instance__']
		if _Instances._vals_.has_key(objkey):
			if hasattr(_Instances._vals_[objkey],attr):
				return getattr(_Instances._vals_[objkey],attr)
		return this._oldgetattr(attr)
	_ot[1].__getattr__=mygetattr
	
	_ot[1]._oldsetattr=_ot[1].__setattr__
	def mysetattr(this, attr, value):
		objkey=this.__dict__['__instance__']
		if not _Instances._vals_.has_key(objkey):
			_Instances._vals_[objkey]=_instance_values()
		if not hasattr(this.__class__, attr) and attr not in this.__class__._otherAttrib:
				return setattr(_Instances._vals_[objkey], attr, value)
		return this._oldsetattr(attr,value)
	_ot[1].__setattr__=mysetattr[/code:2py1z69r]

Hi, Master of Python,

This code works in my case. Thanks.

New member is stored into global (hash)table _Instances._vals_

If an instance has been destroyed, the member of this dead instance in _Instances._vals_ will not be released automatic.

Btw, the variable type in construct only support "Number" and "String", so that I can not store instance directly.

I save the UID of instance and find it from adding an "compared" event, if I only use built-in event sheet (w/o python support).

Question:

Is there a faster way to keep the selected instances (w/o python support)?

With python, I save the {UID:instance} in a (hash)table, and clean the {UID:instance} pair if the instance has been destroyed.

Humm... Maybe I can cover the 'Destroy' method in objAInstance in _Instances to hang my clean method.

Question:

1. What is _Instances?

2. Will objA[0].Destroy() call objAInstance.Destroy()? Is objAInstance the class of objA[0]?

Thank you for your help

I test the "objA[0].Destroy() call objAInstance.Destroy()" is success. Now I can override Destroy method for doing some clean-up processes.

[quote:14olccbt]1. What is _Instances?

It's basically just to hide\organize instance classes from the main global dict. It should never need to be accessed directly. Basically every object type causes 2 classes to be generated ex. Sprite and SpriteInstance. SpriteInstance is a class that points to a particular instance of sprite.

[quote:14olccbt]2. Will objA[0].Destroy() call objAInstance.Destroy()? Is objAInstance the class of objA[0]?

es for the first. For the second objA[0] is a objAInstance.

The only issue is if you destroy the object with events, the python destroy() is not called and the custom methods will not be cleaned up.

Thanks, it's very clear.

Sorry for another question, I try to override System.Create() for the same reason, to add some custom initialize. How to get the class of "System"?

System is a bit different since there is only one instance of System.

get the system class with this:

System.__class__[/code:29imus8b]

It works. Thank you again.