title: Why regex with lookaheads doesn't match?
body: <p>I need (in PHP) to split a sententse by the word that cannot be the first or the last one in the sentence. Say the word is &quot;pression&quot; and here is my regex</p>
  <pre><code>/^.+?(?=[\s\.\,\:\;])pression(?=[\s\.\,\:\;]).+$/i
  </code></pre>
  <p>Live here: <a href="https://regex101.com/r/CHAhKj/1/" rel="nofollow noreferrer">https://regex101.com/r/CHAhKj/1/</a></p>
  <p>First, it doesn't match.
  Next, I think - it is at all possible to split that way? I tryed simplified example</p>
  <pre><code>print_r(preg_split('/^.+pizza.+$/', 'my pizza is cool'));
  </code></pre>
  <p>live here <a href="http://sandbox.onlinephpfunctions.com/code/10b674900fc1ef44ec79bfaf80e83fe1f4248d02" rel="nofollow noreferrer">http://sandbox.onlinephpfunctions.com/code/10b674900fc1ef44ec79bfaf80e83fe1f4248d02</a></p>
  <p>and it prints an array of 2 empty strings, when I expect
  <code>['my ', ' is cool']</code></p>