Search Multiple Tags at Once + And/Or/Exclusion

The search function currently is really bad. If you want to search for more than one tag at a time, you have to type in each tag individually, hitting enter and updating the search each time. Hitting space--which is the intuitive way to delineate search terms in any competent search engine--inputs a hyphen instead, and a hyphenated tag ("tag1-tag2") returns different results than two tags of the same name ("tag1" and "tag2").

Forcing the user to add search terms one-by-one like this is bad enough, but there is also no way to determine the relationship between entered tags. There's no way to exclude a tag you don't want short of adding it to the blacklist--something that is very tedious if it is just one specific search you need and don't want the excluded tag to be blacklisted otherwise--and there is no way to search for submissions that contain just one of the tags you're searching for, rather than expecting it to have all of them. This severely limits the ability to find something specific, as well as makes it difficult and tedious to browse for art that contains one or more of the tags you like.