In message "[ruby-talk:01388] Re: Say hi (bis)"
    on 00/02/16, Yukihiro Matsumoto <matz / netlab.co.jp> writes:

|Hmm, I'm not sure this kind of type inference for totally dynamic
|language like Ruby would work.  In Ruby, even Fixnum#+ can be
|redefined, so that no type information can be used at compile time.
|It's much harder than Perl, which is partially static typed language. 

I found a paper from Proceedings of the 8th International Python Conference:

  Aggressive Type Inference
  http://www.python.org/workshops/2000-01/proceedings/papers/aycock/aycock.html