I didn't read  your example closely, but, generally....

(obj respondsTo: #isCVLambda) and: [ obj isCVLambda ]

is very general (independent of hierarchy), or if you want to trap  
people on a class tree...

obj isKindOf: CVLambda

or trap exceptions for when something doesn't respond to isCVLambda ...

or...

--
BUT, it will be slower.

an intriguing idea is having Object always respond to any pattern  
isXXX with false, unless the method is explicitly defined. (Now there  
I go, changing the root behavior...)

-Cam


On Jun 29, 2009, at 1:18 PM, Igor Stasenko wrote:

> so, here the question, can i implement the same behavior w/o using
> #isCVLambda , and