From: Qian Jigui <qianjigui@...>
Date: 2008-11-20T12:23:45+09:00
Subject: How the Ruby's super work in finding method?

When one method defined in many places, I want to use the super to
invoke them one by one. This is the code:

#########################################
module M
  def report( a = 4, b =5)
    p "M report begin: a=#{a},b=#{b}"
    a = 6
    super(a)
    p "M report end"
  end
end

class B
  def report(a=11,b=12)
    p "B report 1 begin: a=#{a},b=#{b}"
    p "B report 1 end"
  end
  def report(a=13,b=14)
    p "B report 2 begin: a=#{a},b=#{b}"
    #super()
    p "B report 2 end"
  end
end

class C < B
  def report( a=8,b=9)
    p "C report 1 begin: a=#{a},b=#{b}"
    p "C report 1 end"
  end
  def report( a=7,b=3)
    p "C report 2 begin: a =#{a},b=#{b}"
    super()
    p "C report 2 End"
  end
  include M
end

class D < C
  def report( a = 2, b=1)
    p "D report 1 begin: a=#{a},b=#{b}"
    super(a,b)
    p "D report 1 end"
  end
  include M
  def report(a = -2, b=-1)
    p "D report 2 begin: a=#{a},b=#{b}"
    super
    p "D report 2 end"
  end
end

d = D.new
d.report

#########################################
That's the output:

:!ruby testMethodGet.rb
"D report 2 begin: a=-2,b=-1"
"C report 2 begin: a =-2,b=-1"
"M report begin: a=4,b=5"
"B report 2 begin: a=6,b=14"
"B report 2 end"
"M report end"
"C report 2 End"
"D report 2 end"

I find sometimes it will invoke the super class' method first(D->C->M),
but it will invoke the module's method first(C->M->B) too.
I know I include the module in different place in the different classes.
But I don't know the strange working .
Can anyone find the problem?
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