The reason you can do metaprogramming with blocks in Smalltalk and not most other "OO" languages is that Smalltalk is based on message-passing, and you have con

The reason you can do metaprogramming with blocks in Smalltalk and not most other "OO" languages is that Smalltalk is based on message-passing, and you have control over how objects interpret messages sent to them. Specifically, the doesNotUnderstand method is equivalent to having a fully late-bound APPLY in Lisp (which means you can implement FEXPRs yourself when you need them, and FEXPRs are as good as CL or Scheme-style macros for many purposes): http://carcaddar.blogspot.com/2009/04/closure-oriented-metaprogramming-via.html?showComment=1239507240000#c7399536579144180363 http://carcaddar.blogspot.com/2009/04/closure-oriented-metap... http://c2.com/cgi/wiki?DoesNotUnderstand http://c2.com/cgi/wiki?DoesNotUnderstand This is why Alan Kay says message passing is more important than objects.