jsonnet
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feat: allow negative index/end on std.slice
I found myself implementing this elsewhere and figured it'd be easy to support in stdlib.
I ran make test, it succeeded for my changes but had unrelated failures, we might want to fix that in a separate PR.
@sbarzowski Will this "just work" on go-jsonnet?
I think I was originally opinionated about not supporting this as I wanted the language to be simple... But in retrospect it seems more confusing to support python slicing only "partially" so this seems a good idea.
Will this "just work" on go-jsonnet?
Yes. I think we just desugar to std.slice. That said ideally we would add a builtin (but that's neither easier nor harder with this change in).
BTW this change definitely requires an update to documentation.
It seems like this was almost ready to go back in June, with only a request for documentation updates as a possible blocker. @Duologic would you like to contribute some doc changes for this, or should I work on it?
@sparkprime I'm not sure if there is any coordination needed with other jsonnet implementations to get this out? I assume we merge it here first, then go-jsonnet can pick it up (probably with the next release?) and other implementations (e.g., jrsonnet - which has a PR queued already, https://github.com/CertainLach/jrsonnet/pull/117) can update at their leisure.
I just scanned the documentation and didn't find any mention that negative slices are not supported, am I missing something?
Do you want an example added maybe?
Hmm... it's a good point, the tutorial says "Array slices like arr[10:20:2] are allowed, like in Python", so perhaps people have always assumed negative slices worked :-)
IMHO, yes, it would be good to add an example of a negative index in the std.slice documentation in the standard library reference.