Function runtime_index_lookup_sequence 

pub fn runtime_index_lookup_sequence<F>(
    cx: &mut Cx,
    lookup: F,
    first_index: i64,
) -> Result<Value>
where
    F: Fn(&mut Cx, i64) -> Result<Option<Value>> + Send + Sync + 'static,

Builds a lazy sequence over contiguous integer keys from a lookup function.