From: Daniel Schierbeck <daniel.schierbeck@...>
Date: 2005-11-17T06:37:17+09:00
Subject: Object#to_b

Currently, as far as I know, `if' and `unless' merely check if an object 
is of either types NilClass or FalseClass. This seems to contradict the 
duck-typing paradigm. I propose that we implement a method Object#to_b 
that is called by `if' and `unless'. It should return a boolean value. 
That way, a developer can decide whether or not an object should 
evaluate to true or false.

   class Connection
     def open?; end
     def closed?; end
     def to_b; open?; end
   end

   connection = Connection.new(...)
   if connection
     # ...
   end

Implementation:

   class Object
     def to_b
       true
     end
   end

   class FalseClass
     def to_b
       false
     end
   end

   class NilClass
     def to_b
       false
     end
   end


One problem I see with this proposal is that it seems like a lot of 
people check if a variable has been set by writing `if var ...'. This 
change would require that people wrote `unless var.nil?', which I 
personally find more correct as well.


Cheers,
Daniel