Function ident 

pub fn ident() -> impl Parser<Token, SmolStr, Error = Simple<Token>> + Clone

Parse an identifier (unquoted, escaped, or keyword used in identifier position).

Cypher allows most keywords to be used as identifiers in non-ambiguous contexts (variable names, labels, property names, map keys, relationship types).

Uses filter_map instead of select! to avoid monomorphization bloat from 70+ arms, which otherwise causes linker failures from excessively long symbol names.