If you check out the implementations at the bottom of the post, you'll see that, at runtime, if biscuits is an object they index into `obj["-"]`. And if it's an array, they special-case "-" and index into `array[length]`.
i rather see they implement jsonpath - https://tools.ietf.org/id/draft-goessner-dispatch-jsonpath-0... instead of inventing their own xpath-like expression language tbh.
Edit: i suppose i shouldn't be surprised there's multiple standards to varying degrees of acceptance: https://datatracker.ietf.org/doc/html/rfc6901 so may be it is fine to use this expression language...
No, that’s specified in the JSON Pointer spec, which this spec depends on: https://datatracker.ietf.org/doc/html/rfc6901
> […] that's not fully specified by just the spec?
Specs depend on previous specs nearly all the time. Thank goodness for hyperlinks.
It also shows this in the Pointer spec.