internal override IEnumerable <ParseStep> Parse(IRegexEngine engine)
{
yield return(ParseStep.BeginParse(this, engine.State));
if (engine.State.Index >= engine.Input.Length)
{
yield return(ParseStep.Fail(this, engine.State, engine.State));
yield return(ParseStep.Break(this));
yield break;
}
if (Matches(engine.Input[engine.State.Index]))
{
var match = engine.Input.Substring(engine.State.Index, 1);
var initialState = engine.State;
engine.State = engine.State.Advance();
yield return(ParseStep.Pass(this, match, initialState, engine.State));
yield return(ParseStep.AdvanceIndex(this, engine.State));
yield return(ParseStep.Break(this));
}
else
{
yield return(ParseStep.Fail(this, engine.State, engine.State));
yield return(ParseStep.Break(this));
}
}