# File lib/math_ml/latex.rb, line 219
                        def scan_num_of_parameter
                                if @scanner.scan_option
                                        raise parse_error("Need positive number.", @scanner[1]+"]") unless @scanner[1]=~/\A#{RE::SPACE}*\d+#{RE::SPACE}*\z/
                                        @scanner[1].to_i
                                else
                                        0
                                end
                        end