llwaeva@21cn.com wrote:
hi there, I am working with a TAG-oriented text with boost:regex. For example, the following pattern might occur in the text
<before> <pre><p>Some Text</p></pre> <after> <pre> ddd </pre>
In this case, I would like to extract everything between <pre> </pre>. Meanwhile, everything outside <pre> </pre> should be unchanged except that < is replaced by < and > is replaced by >
For that purpose, I tried the following code
I don't see anything obviously too wrong based on a quick glance except that \s* should be \\s*. If that doesn't fix things, post a self contained test case and I'll take a look.
In a far more complicated case, a nested <pre></pre> might occur as follow
<before> <pre><pre><p>Some Text</p></pre></pre> <after> <pre> ddd </pre>
For this case, I only want to handle the outermost <pre></pre> and keep everything inside it unchanged, i.e., the inner <pre></pre> will be extracted as common text.
Hmmmm, traditional regexes don't handle that all that well, how deep will the nesting go? You handle a finite number of nested occurences using something like: <\s*pre[^>]*>(<\s*pre[^>]*>.*?</\s*pre\s*>|.)*?</\s*pre\s*> and so on, but remember to double those \'s if you embed this in a C++ string. John.