Exclusive fromTags

[MightyAlex200]

So far we have a function in posts called fromTags that gives all posts with any of the given tags. I'd like to have a function that gives all posts that have all of the given tags. Or perhaps better, a search function that takes input like "(1 & (2 &| (3 | 4)) & !5)" and returns all posts tagged 1 AND (2 OR (3 XOR 4)) AND NOT 5 (working syntax, probably want something better than that)