# File lib/rgl/traversal.rb, line 127
127:     def self.def_event_handler (m)
128:       params = m =~ /edge/ ? "u,v" : "u"
129:       self.class_eval %{
130:         def handle_#{m} (#{params})
131:           @#{m}_event_handler.call(#{params}) if defined? @#{m}_event_handler
132:         end
133: 
134:         def set_#{m}_event_handler (&b)
135:           @#{m}_event_handler = b
136:         end
137:       }
138:     end