pub fn parse_var_ref(source: &str) -> Result<Vec<String>, LexerError>Expand description
Parse a variable reference, extracting the path segments.
Input: "${VAR.field[0].nested}" → ["VAR", "field", "[0]", "nested"]
The [...] collector is quote-aware (GH #183): a subscript opening with
" or ' consumes verbatim up to its OWN matching closing quote before
resuming the search for the subscript’s terminating ] — so an embedded
] inside a quoted key (${r["weird]key"]}) is just data, not the
bracket’s end. Un-quoted subscripts ([0], [$k], [web]) are
unaffected — the quote check only fires when the subscript’s first
character is actually a quote.