Appendix A. Fluidinfo Query Language Reference
Tag Presence: The has Operator
has operator matches objects
that are tagged with the named tag. For instance,
matches all objects to which Alice has attached her
rating tag—all four objects in Figure A-1. Similarly,
would match only Led Zeppelin IV since that’s the only object to which Γλαύκων has attached a rating.
The value of the tag does not matter; even a tag with no value
will be matched by the
Equality: The = Operator
The values of any tag having a simple native type can be tested with an explicit query of the form
tag is the name of a tag and
value is a specification of a matching
In the case of numbers, the operator tests exact numeric equality, so that both
alice/rating = 5
alice/rating = 5.0
match any objects that Alice has tagged with a rating of 5 (or 5.0).
String values will not match these queries (for example, tags with textual
"5.0"). In Figure A-1 only the Led Zeppelin album,
IV, will match.
In the case of booleans (true/false values), the words
false will match, regardless of
alice/likes = true alice/likes = false
In the Figure A-1, only Emma will match the first query, and only Animal Farm will match the second query.
No numeric or textual values will ...