public override (Counter Initial, List <Transform> Transforms) VisitProgram(ChemsParser.ProgramContext context)
{
var initials = context.initial().token().GroupBy(tok => tok.GetText()).ToDictionary(ite => ite.Key, ite => ite.Count());
var counter = new Counter(initials);
var rv = new RuleVisitor();
var transforms = context.rule().Select(rv.VisitRule).ToList();
return(counter, transforms);
}