Type Alias Variables 

pub type Variables = IndexMap<String, Value>;

Variables a document may reference with $name.

A nested structure, walked one path segment at a time: $a.b[0] descends through a Value::Hash and then a Value::Array. Upstream stores arbitrary JavaScript here and descends with hasOwnProperty; Value is the same lattice with a name.

Aliased Type

pub struct Variables { /* private fields */ }