解析平衡的嵌套wiki模板并提取单行参数'；s的内容

我知道解析嵌套字符串或HTML最好由真正的解析器来完成，但在我的情况下，我有简单的模板，希望从模板中提取Wiki参数"title"的标题内容。我花了一段时间才做到这一点，但多亏了Lars Olav Torvik的正则表达式工具(http://regex.larsolavtorvik.com/)和这个用户论坛在这里我得到了它。可能有人觉得它有用。（我们都想贡献，他，不是吗？；-）下面用注释注释的代码就可以了。我不得不用环视断言来做这件事，以免两个模板混合在一起，因为其中一个模板中没有标题。

我还不确定regex注释中的两个问题——参见(?# Questions: …)——是否理解了(?R)中的递归部分。它是否从最外层定义的级别（即第二行正则表达式'{'{和最后一行正则表达式'}'}）获取要检查的内容？这是正确的吗？在(?R)展位同等工作之前，++和+之间的区别是什么。

1. 页面上的原始wiki模板（最简单）：

   $wikiTemplate = "
   {{Templ1
   | title = (1. template) title
   }}
   {{Templ2
   | any parameter = something {{template}}
   }}
   {{Templ1
   | title = (3. template) title
   }}
   ";
   

2. 更换：

   $wikiTemplate = preg_replace(
     array(
     // tag all templates with START … END and add a TITLE-placeholder before
     // and take care of balanced {{ …  }} recursiveness 
       "@(?s)   (?# switch to dotall match, i.e. also linebreaks )
         '{'{ (?# find two {{ )
         (?: (?# group 1 as a non-backreferenced match  )
           (?:  (?# group 2 as a non-backreferenced match  )
             (?! (?# in group 1 anything but not {{ or }} )
               '{'{ 
               |   (?# or )
               '}'}
             )
             .
           )++  (?# Question: what is the differenc between ++ and + here? )
           |    (?# or )
           (?R) (?# is it recursive of what is defined in the outermost,
                 i.e. 2nd regexp line with '{'{ and last line with '}'}
                 Question: is that here understood correctly? ) 
         )
         * (?# zero or many times of the inner regexp defintions )
         '}'} (?# find two }} )
       @x",// x-extended → ignore white space in the pattern
     // replace TITLE by single line content of title parameter 
       "@
         (?<=TITLE) (?# TITLE must preceed the following linebreak but is not
                     backreferenced within ''0, i.e. the whole returned match)
         (['n'r]+)  (?#linebr in 1 may also described as . because of
                     s-modifier dotall)
         (?:        (?# start non-backreferenced match )
           .        (?# any character but not followed by START)
           (?!START)
         )+      (?# multiple times)
         (?:     (?# start non-backreferenced match )
           '|'s*title's*='s* (?#find the parameter '| title = ')
         )
         ([^'r'n]+)  (?#get title now to ''2 but exclude the line break. 
                      Note it is buggy when there is no line break )
         (?:     (?# start non-backreferenced match )
           .     (?# any character but not followed by END)
           (?!END)
         )
         +       (?# multiple times)
         .       (?# any single character, e.g. the last  because as all
                  stuff before captures anything not followed by END)
         (?:END) (?#a not backreferenced END)
       @msx", // m-multiline, s-dotall match also linebreaks,
              // x-extended → ignore white space in the pattern
     ), 
     array(
       "TITLE'nSTART''0END", // '0 is the whole returned match, i.e. the template
     # replace the TITLE to  TITLEtitle contentTITLE…
       "''2TITLE''0",
     ),
     $wikiTemplate
   );
   print_r($wikiTemplate);
   

3. 然后输出的标题由每个模板上方的TITLE标记，但前提是有标题：

   TITLE(1. template) titleTITLE
   START{{Templ1
    | title = (1. template) title
   }}END
   TITLE
   START{{Templ2
    | any parameter = something {{template}}
   }}END
   TITLE(3. template) titleTITLE
   START{{Templ1
    | title = (3. template) title
   }}END
   

我对regexp的理解或一些改进有什么疑问吗？谢谢你，安德里亚斯。