# File lib/math_ml/latex.rb, line 910
                        def grp_left_etc
                                right =
                                        case @scanner[1]
                                        when "left"
                                                "right"
                                        when "bigg"
                                                "bigg"
                                        end

                                f = Fenced.new
                                p = @scanner.pos
                                o = @scanner.scan_any
                                raise ParseError.new('Need brace here.') unless o && (o=~RE::BRACES || @delimiters.include?(o[RE::COMMANDS, 1]))
                                f.open = (o=~RE::BRACES ? o : parse_symbol_command(o[RE::COMMANDS, 1], true))
                                f << push_container(Row.new) do |r|
                                        until @scanner.peek_command==right
                                                if @scanner.eos?
                                                        @scanner.pos = p
                                                        raise ParseError.new('Brace not closed.')
                                                end
                                                r << parse_to_element(true)
                                        end
                                end
                                @scanner.scan_command # skip right
                                c = @scanner.scan_any
                                raise ParseError.new('Need brace here.') unless c=~RE::BRACES || @delimiters.include?(c[RE::COMMANDS, 1])
                                f.close = (c=~RE::BRACES ? c : parse_symbol_command(c[RE::COMMANDS, 1], true))
                                f
                        end