From: Philipp Kern <trash@...>
Date: 2005-05-28T08:15:20+09:00
Subject: Coercion and ranges

Dear Ruby fellows,

what is the reason behind the fact that there is no generic coercion 
system apart from the additional overhead?

Concretly I tried to add some ranges. Childish as I am I thought of a 
straightforward way by implementing Range#+:

class Range
   def +(other)
     self.entries + other.entries
   end
end

However, this does not work on multiple ranges as a temporary array is 
constructed, which does not know of the ability to coerce ranges to arrays.

irb(main):001:0> (?A..?C) + (?a..?c)
=> [65, 66, 67, 97, 98, 99]
irb(main):002:0> (?A..?C) + (?a..?c) + (?0..?3)
TypeError: cannot convert Range into Array
         from (irb):2:in `+'
         from (irb):2

 From my understanding the conversion should happen automatically when 
coercion is properly implemented. Surely one could just add "to_a" to 
all the ranges, but it certainly made me pondering about it.

Kind regards,
Philipp Kern