I would like to search for files that have alternatively a tag or another. It would be great if we could create a more complex expression to match tagged files.The problem can be solved with a simple separator pattern (like "|") which create an alternative search criteria.

Example: a search like "+foo | +bar baz | -qux" should find files that are, alternatively:
tagged with "foo" ;
tagged with "bar" and have "baz" in the file name;
not tagged with "qux".