From: Jim Cain <list@...>
Date: 2003-07-18T14:10:24+09:00
Subject: Aliased setter methods behave differently than other methods?

Here's another question... I am aliasing and redefining certain methods,
determined at runtime. Normal methods work fine, but methods ending in
'=' are not behaving the same. Here's an example:

module Mymodule
    def Mymodule.append_features(klass)
       super(klass)
       klass.module_eval do
          def self.enalias(s)
             alias_method(('old_' + s).intern, s.intern)
             module_eval <<-EOF
                def #{s}(arg)
                   puts 'hola ' + arg
                   old_#{s}(arg)
                end
             EOF
          end
       end
    end
end

class Myclass
    def hello(s)
       puts 'hello ' + s
    end
    include Mymodule
end

class MyclassQ
    def hello=(s)
       puts 'hello ' + s
    end
    include Mymodule
end

c = Myclass.new
c.hello('1')
Myclass.enalias('hello')
c.hello('2')
c.old_hello('3')
puts '-----'
q = MyclassQ.new
q.hello=('1')
MyclassQ.enalias('hello=')
q.hello=('2')
q.old_hello=('3')

This outputs the following:

hello 1
hola 2
hello 2
hello 3
-----
hello 1
hola 2
hello 3

Notice that, in the class where the method is "hello=" rather than
"hello", the call to the old method fails somehow. Its output is skipped.

Am I missing something obvious here? Are the setters intended to act
differently somehow? BTW I get this output on both 1.6.8 and 1.8.