moving away from the attributes aproach, tests fixed

lib/sof/writer.rb

@@ -0,0 +1,46 @@
+module Sof
+  class Writer
+    def initialize members
+      @members = members
+    end
+
+    def write
+      io = StringIO.new
+      output io , @members.root
+      io.string
+    end
+
+    def output io , object
+      if Members.is_value?(object)
+        object.to_sof(io , self)
+        return
+      end
+      occurence = @members.objects[object]
+      raise "no object #{object}" unless occurence
+      indent = " " * occurence.level
+      io.write indent
+      if(object.respond_to? :to_sof)
+        object.to_sof(io , self)
+      else
+        io.write object.class.name
+        if( object.respond_to?(:attributes))
+          object.attributes.each do |a|
+            val = object.send a
+            io.write( a )
+            io.write( " " )
+            output( io , val)
+          end
+          io.puts ""
+        else 
+          raise "General object not supported (yet), need attribute method #{object}"
+        end
+      end
+    end
+
+    def self.write object
+      writer = Writer.new(Members.new(object) )
+      writer.write
+    end
+    
+  end
+end