# File lib/erubis/engine/ec.rb, line 72
    def add_expr_debug(src, code)
      code.strip!
      s = nil
      if code =~ /\A\".*?\"\s*,\s*(.*)/
        s = $1.gsub(/[%"]/, '\\\1') + '='
      end
      src << @indent if src.empty? || src[-1] == ?\n
      src << " fprintf(stderr, \"*** debug: #{s}\" #{code});"
    end