RegEx in PHP (LaTeX-itemnize)

Question

It try so get some information out of LaTeX documents. However I tried to convert http://regex101.com/r/kB7nD4 into php code using "preg_replace" but there occurs many errors.

The RegEx is

\\item(([\s\S]*)^[^\\item]+\\(?!\\item))

and should extract the list items from the latex enumerate enviroment. But

$newlatex = preg_replace('/\\\\item(([\\s\\S]*)^[^\\\\item]+\\\\(?!\\\\item))/m','<li>$1</li>',$oldlatex);

Can somebody give me an advice? Can this expression be simplified.

Answer 1

I ran this code with no problems

<?php
$string='Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.

\begin{itemnize}
\item first outer
      first outer second line
  \begin{itemnize}
    \item first inner first line with $x^2=y$
          first inner second line
    \item second inner
   \end{itemnize}
   \item second out
\end{itemnize}


Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dol';
//
$newlatex = preg_replace('/\\\\item(([\\s\\S]*)^[^\\\\item]+\\\\(?!\\\\item))/m','<li>$1</li>',$string);
print($string);
print($newlatex);

producing this result

\begin{itemnize}
<li> first outer
      first outer second line
  \begin{itemnize}
    \item first inner first line with $x^2=y$
          first inner second line
    \item second inner
   \end{itemnize}
   \</li>item second out
\end{itemnize}

no apparent errors could you give more details on your errors?