# File lib/math_ml/latex.rb, line 190
                        def parse_error(message, rest="", whole=nil)
                                rest = whole[/\A.*?(#{Regexp.escape(rest)}.*\z)/, 1] if whole
                                rest << @scanner.rest
                                done = @scanner.string[0, @scanner.string.size-rest.size]
                                ParseError.new(message, rest, done)
                        end