compile

# File lib/erb.rb, line 596
    def compile(s)
      enc = s.encoding
      raise ArgumentError, "#{enc} is not ASCII compatible" if enc.dummy?
      s = s.b # see String#b
      enc = detect_magic_comment(s) || enc
      out = Buffer.new(self, enc)

      content = ''
      scanner = make_scanner(s)
      scanner.scan do |token|
        next if token.nil?
        next if token == ''
        if scanner.stag.nil?
          case token
          when PercentLine
            add_put_cmd(out, content) if content.size > 0
            content = ''
            out.push(token.to_s)
            out.cr
          when :cr
            out.cr
          when '<%', '<%=', '<%#'
            scanner.stag = token
            add_put_cmd(out, content) if content.size > 0
            content = ''
          when "\n"
            content << "\n"
            add_put_cmd(out, content)
            content = ''
          when '<%%'
            content << '<%'
          else
            content << token
          end
        else
          case token
          when '%>'
            case scanner.stag
            when '<%'
              if content[-1] == \n\
                content.chop!
                out.push(content)
                out.cr
              else
                out.push(content)
              end
            when '<%='
              add_insert_cmd(out, content)
            when '<%#'
              # out.push("# #{content_dump(content)}")
            end
            scanner.stag = nil
            content = ''
          when '%%>'
            content << '%>'
          else
            content << token
          end
        end
      end
      add_put_cmd(out, content) if content.size > 0
      out.close
      return out.script, enc
    end