private Nonterminal Map(RuleExpr rule)
{
if (!Rules.TryGetValue(rule, out var mapped))
{
mapped = new Nonterminal(rule.Name);
Rules.Add(rule, mapped);
mapped.Body = Map(mapped, rule.Body);
}
return(mapped);
}
public Grammar From(RuleExpr startSymbol)
{
return(new Grammar(Map(startSymbol)));
}
