> it was new news to meet the semantics of `proc' differed from Proc.new
> so radically!

Well, that was my point and what my example was supposed to
demonstrate:
in ruby18, proc is a synonym for lambda but in ruby19 it's an alias
for
Proc.new.

http://eigenclass.org/hiki/Changes+in+Ruby+1.9#l47

Regards,
Thomas.