trim_line1

# File lib/erb.rb, line 426
      def trim_line1(line)
        line.scan(/(.*?)(<%%|%%>|<%=|<%#|<%|%>\n|%>|\n|\z)/) do |tokens|
          tokens.each do |token|
            next if token.empty?
            if token == "%>\n"
              yield('%>')
              yield(:cr)
            else
              yield(token)
            end
          end
        end
      end