Hi gurus and nubys,

You can find the full text at
http://rcrchive.net/rcr/RCR/RCR280
(sorry if there are typos/errors, I'm having some problems with the 
submit phase).

The proposed system unifies the various way to convert or to extract an 
object from another, like to_f, to_set, Integer() or to_enum.
It also allows declarative checking of the type of an object and reduces 
duplication of code. Yes, I mean type, not class ;).

But it's not something really new and does not break compatibility at 
all, it is mostly a refactoring and generalization of already used 
practices.

Anyway I think you could understand better reading the rationale and 
sample implementation on the rcr page. If you're going to vote against 
this please take some time to comment on why you did it, it would be 
much more useful.

Finally I'd like to thank Paul Brannan for helping me in refining this 
and David Black for the great help in the rcr publishing process :)