Walter

>Not sure whether I do understand you here. Why is type checking in dynamic langugage much more difficult *if* the type is specified at the declaration at the top ?

because there are many kinds of dynamics at work - there is a reason interfaces were established in COM <g>.
Most (if not all) current scripting languages object creation is analogous to a simple factory pattern in the strict/single inheritance world. Then you have python, were all variables are name bindings pointing to objects and the usual properties (from vfp OOP-model speak) are divided into class and instance variables - setting instance variables is a behaviour I view to be nearer to vfp's addobject() than .Net/java field and property mechanisms (Gary: this was the reason I cc'ed you - I have not used Ironpython, but I guess it follows the normal CPython ways). You can exchange/overwrite name bindings for functions and methods at runtime, also via indirect factory patterns - some of the things I read are much harder to follow as the level of creativity (spoken with ironic emphasis, as this is not always good in enterprize dev <bg>) is MUCH higher.

regards

thomas