# File lib/math_ml/latex.rb, line 1021
                        def env_array_row(layout)
                                l = Scanner.new(layout)
                                r = Tr.new
                                first_column = true
                                vlined = l.check(/\|/)
                                until l.eos?
                                        c = l.scan(/./)
                                        if c=='|'
                                                r << Td.new if vlined
                                                vlined = true
                                                next
                                        else
                                                vlined = false
                                                case c
                                                when 'r', 'l', 'c'
                                                when '@'
                                                        r << parse_into(l.scan_any, Td.new)
                                                        next
                                                end
                                                if first_column
                                                        first_column = false
                                                else
                                                        raise ParseError.new("Need more column.", @scanner.matched.to_s) unless @scanner.scan(/&/)
                                                end
                                                r << push_container(Td.new) do |td|
                                                        td << parse_to_element(true) until @scanner.peek_command=="end" || @scanner.check(/(&|\\\\)/) || @scanner.eos?
                                                end
                                        end
                                end
                                r << Td.new if vlined
                                raise ParseError.new("Too many column.") if @scanner.check(/&/)
                                r
                        end