Open classes makes invention possible in real time. No committee. No waiting for the next language revision. If you think of it, you can try it. Does Symbol#to_proc make it worthwhile? How about andand? Why don’t you tell me? I was serious when I asked you what you think of it.
and soon after .. this ..
I am all with Raganwald that "dangerous features enable bottom-up language evolution". My main concern, however, is that, I have seen too much of Ruby code where people tend to open up classes without even considering other design choices. On many of these occasions did I feel that mixins could have been a more pragmatic alternative. Maybe, one reason could be that, open classes in Ruby are too easy to implement. And developers give in to the temptation of using this "dangerous feature", without giving the adequate amount of thought that the design decision deserves. Scala's lexically scoped alternative is less sexy, but looks more pragmatic.