pub fn lookup<'a>(
value: &'a Value,
path: &[String],
command: Option<&str>,
) -> Option<&'a Value>Expand description
Walks a dotted path inside value.
GAP-SG-230: when the last segment names a field this project spells more than
one way, the sibling spellings are tried before answering None. This is the
one place worth doing it, because it is the ONE accessor all four shaping
knobs share — FilterExpr::matches, super::shape::sort,
super::shape::dedupe and shape::project_with all reach the payload
through here. Resolving anywhere upstream would have meant rewriting the
caller’s key in four places, and FilterExpr keeps its path private
precisely so nobody does that.
The fallback runs only when the direct walk already failed, so the hot path
pays one Option test and nothing else. A payload that carries the requested
spelling never consults the table at all.
GAP-SG-274: command is the subcommand slug the surface resolved, and it
selects which groups of the table are in force — kind names the entity type
under graph and the line discriminator under graph-ndjson.