If I understand what OP means by "and", it doesn't mean "(abc OR def) AND (123 OR 456)" — it means "(abc OR def) FOLLOWED BY (123 OR 456)". Let's look at another example, with a hypothetical & operator:

   /(\D\S)+/
   /(\D|\S)+/
   /(\D&\S)+/

If you look at the string "b5 ", the first regex matches "b5", the second regex matches the whole string because all of the characters are either not a number or not whitespace, and the third regex only matches "b", because that's the only character that is both not a number and not whitespace.