# File lib/yaml/ypath.rb, line 9
        def initialize( str )
            @segments = []
            @predicates = []
            @flags = nil
            while str =~ /^\/?(\/|[^\/\[]+)(?:\[([^\]]+)\])?/
                @segments.push $1
                @predicates.push $2
                str = $'
            end
            unless str.to_s.empty?
                @segments += str.split( "/" )
            end
            if @segments.length == 0
                @segments.push "."
            end
        end