Derived-class initialization

ruby-talk
1

Hello all,

I'm having some trouble with extending an existing Ruby class in order
to add functionality. Here's some example code:

class Graph
  ....
  ....
  def subgraph(*args)
    graph = self.new
    ....
    ....
    return graph
  end
end

class AwesomeGraph < Graph
  ....
  ....
  def do_something
    ....
    ....
  end
end

g = AwesomeGraph.new
a = g.subgraph(g.nodes)
a.do_something // ERROR! No Graph#do_something exists!

I was hoping 'self.new' would take into account the derived class used
upon creation, but it doesn't.

Any suggestions?

···

--
Thanks!
Bryan
--
Posted via http://www.ruby-forum.com/.

2

This looks suspect, 'self' in this method looks like it will refer to the
Graph instance, not the Graph class. Try self.class.new instead.

···

2009/3/18 Bryan Richardson <btrichardson@gmail.com>

Hello all,

I'm having some trouble with extending an existing Ruby class in order
to add functionality. Here's some example code:

class Graph
....
....
def subgraph(*args)
   graph = self.new
   ....
   ....
   return graph
end
end

--
James Coglan

3

Yep... that worked. :slight_smile:

···

--
Thanks!
Bryan

James Coglan wrote:

2009/3/18 Bryan Richardson <btrichardson@gmail.com>

   ....
   ....
   return graph
end
end

This looks suspect, 'self' in this method looks like it will refer to
the
Graph instance, not the Graph class. Try self.class.new instead.

--
Posted via http://www.ruby-forum.com/\.