public override IEnumerable <ExpressionResult> RunInternal(ExpressionContext context)
{
if (!context.Local.Consuming)
{
throw new InvalidOperationException("Character classes cannot be used without input.");
}
if (context.Local.IsAtEnd)
{
yield break;
}
var c = context.Local.Input[context.Local.Index];
if (CharacterClass.Accepts(c))
{
context.Consume(1);
context.Produce(c.ToString());
yield return(new(c.ToString()));
context.Unproduce();
context.Unconsume(1);
}
}
