{escaped-token (jsonptr "/~2")
 extra (contains? {} a false)
 list-key (contains? [a] ["0"])
 map-index (contains? {a 1} [0.5])
 missing (contains?)
 missing-path (contains? {})
 negative-index (contains? [a] -1)
 path-type (contains? {a 1} true)
 scalar-intermediate (contains? {a 1} [a b])}