# File lib/yaml/ypath.rb, line 25
        def YPath.each_path( str )
            #
            # Find choices
            #
            paths = []
            str = "(#{ str })"
            while str.sub!( /\(([^()]+)\)/, "\n#{ paths.length }\n" )
                paths.push $1.split( '|' )
            end

            #
            # Construct all possible paths
            #
            all = [ str ]
            ( paths.length - 1 ).downto( 0 ) do |i|
                all = all.collect do |a|
                    paths[i].collect do |p|
                        a.gsub( /\n#{ i }\n/, p )
                    end
                end.flatten.uniq
            end
            all.collect do |path|
                yield YPath.new( path )
            end
        end