explicit_trim_line

# File lib/erb.rb, line 374
      def explicit_trim_line(line)
        line.scan(/(.*?)(^[ \t]*<%\-|<%\-|<%%|%%>|<%=|<%#|<%|-%>\n|-%>|%>|\z)/m) do |tokens|
          tokens.each do |token|
            next if token.empty?
            if @stag.nil? && /[ \t]*<%-/ =~ token
              yield('<%')
            elsif @stag && token == "-%>\n"
              yield('%>')
              yield(:cr)
            elsif @stag && token == '-%>'
              yield('%>')
            else
              yield(token)
            end
          end
        end
      end