1use std::collections::{BTreeMap, BTreeSet}; 2 3use cfg_symbol::Symbol; 4 5/// The representation of FIRST and FOLLOW sets. 6pub type PerSymbolSets = BTreeMap<Symbol, BTreeSet<Option<Symbol>>>; 7 8pub trait PredictSets { 9 fn predict_sets(&self) -> &PerSymbolSets; 10}