From: Jim Freeze <jim@...>
Date: 2001-04-28T04:08:18+09:00
Subject: [ruby-talk:14346] case and to_s

Hi:

I am trying to add a clase to a list depending upon the
type of the class. Since there are several types of
classes, I am using a case statement. But, the way I
am using the case statement causes the << to call
#to_s, which I don't want it to do.
Here is the error followed by the code.
Can someone please explain this behavior to me?
Tnanks

./dev.rb
./dev.rb:21:in `===': failed to convert Class into String (TypeError)
        from ./dev.rb:21:in `add_device'
        from ./dev.rb:32
        from ./dev.rb:32:in `each'
        from ./dev.rb:32


--begin code--
#! /usr/local/bin/ruby


class DeviceA
  def initialize(a,b)
    @a = a
    @b = b
  end
end

class Assembly
  def initialize
    @devlist = []
  end
  def add_device(d)
    # This line works
    #@devlist << d if DeviceA == d.type

    # These 4 lines cause an error
    case d.type
      when /DeviceA/
        @devlist << d
    end
  end
end

xdev = []
xdev << DeviceA.new("a","b")
xdev << DeviceA.new("A","B")

assembly = Assembly.new
xdev.each { |x| assembly.add_device x }
--end code--

=========================================================
Jim Freeze
jim@freeze.org
---------------------------------------------------------
No comment at this time.
http://www.freeze.org
=========================================================