public void AddTransition(string condition, State nextState)
{
Transitions.Add(Transition.Parse(condition, this, nextState));
if (AmountOfTapes == 0)
{
AmountOfTapes = Transitions.First().AmountOfTapes;
return;
}
if (Transitions.Any(c => c.AmountOfTapes != AmountOfTapes))
{
throw new ArgumentException("The amounts of tapes required differs among the conditions.");
}
}
public bool IsLoopFixedPoint()
{
if (Transitions == null || !Transitions.Any())
{
return(true);
}
var nextCondition = Transitions.First().Node.CurrentCondition;
return(CurrentCondition.Count == nextCondition.Count &&
CurrentCondition.All(a => nextCondition.ContainsKey(a.Key) && nextCondition[a.Key] == a.Value) &&
Transitions.First().Node.IsLoopFixedPoint());
}
public void Transition(string token)
{
// First check that we have that token defined
if (!Tokens.Contains(token))
{
throw new ArgumentOutOfRangeException(nameof(token), token, "Given token is not defined.");
}
// And that we have a transition for this token
if (!Transitions.Any(t => t.Token == token && t.From == CurrentState))
{
throw new ArgumentOutOfRangeException(nameof(token), token, $"No transition exists for {CurrentState} + {token}.");
}
// Get list of possible transitions...
var possible = Transitions.Where(t => t.From == CurrentState && t.Token == token).ToList();
// Check validity of transition
do
{
var transition = possible.MinBy(t =>
{
if (t.TransitionMode != Mode.Pop)
{
return(0);
}
var distanceTo = Stack.IndexOf((T)t.To);
return(distanceTo == -1 ? int.MaxValue : distanceTo);
});
switch (transition.TransitionMode)
{
case Mode.Pop:
var pop = Stack.IndexOf((T)transition.To);
if (pop == -1)
{
possible.Remove(transition);
continue;
}
for (var i = 0; i < pop; i++)
{
Stack.RemoveAt(0);
}
break;
case Mode.Push:
transition = Transitions.First(t => t.Token == token && t.From == CurrentState);
Stack.Insert(0, (T)transition.To);
break;
case Mode.PushPop:
transition = Transitions.First(t => t.Token == token && t.From == CurrentState);
if (Stack.Count > 0)
{
Stack.RemoveAt(0);
}
Stack.Insert(0, (T)transition.To);
break;
}
CurrentState?.Enter();
Transitioned?.Invoke(transition);
return;
} while (Transitions.Count > 0);
}
