# File lib/maruku/ext/math/mathml_engines/ritex.rb, line 3
        def convert_to_mathml_ritex(kind, tex)
                begin
                        if not $ritex_parser
                                require 'ritex'
                             $ritex_parser = Ritex::Parser.new
                        end
                        
                        mathml =  $ritex_parser.parse(tex.strip)
                        doc = Document.new(mathml, {:respect_whitespace =>:all}).root
                        return doc
                rescue LoadError => e
                        maruku_error "Could not load package 'ritex'.\n"+
                        "Please install it using:\n"+
                        "   $ gem install ritex\n\n"+e.inspect
                rescue Racc::ParseError => e
                        maruku_error "Could not parse TeX: \n#{tex}"+
                                "\n\n #{e.inspect}"
                end
                nil
        end