private bool VisitNodeInCycle(TicNode node)
{
node.VisitMark = NotVisited;
_cycle.Push(node);
if (_cycleInitiator != node)
{
//continue to collect cycle route
return(false);
}
// Ref and/or ancestor cycle found
// That means all elements in cycle have to be merged
// (a<= b <= c = a) => (a = b = c)
var merged = SolvingFunctions.MergeGroup(_cycle.Reverse());
// Cycle is merged
_cycle = null;
_cycleInitiator = null;
// continue toposort algorithm
return(Visit(merged));
// Whole cycle is not found yet
// step back
}
public SolvingNode[] Toposort()
{
int iteration = 0;
while (true)
{
var allNodes = _syntaxNodes.Concat(_variables.Values).Concat(_typeVariables).ToArray();
if (iteration > allNodes.Length * allNodes.Length)
{
throw new InvalidOperationException("Infinite cycle detected. Types cannot be solved");
}
iteration++;
var result = NodeToposortFunctions.Toposort(allNodes);
switch (result.Status)
{
case SortStatus.MemebershipCycle: throw new InvalidOperationException("Reqursive type defenition");
case SortStatus.AncestorCycle:
{
var cycle = result.Order;
Console.ForegroundColor = ConsoleColor.Yellow;
Console.WriteLine($"Found cycle: ");
Console.ResetColor();
Console.WriteLine(string.Join("->", cycle.Select(r => r.Name)));
//main node. every other node has to reference on it
SolvingFunctions.MergeGroup(cycle);
Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine($"Cycle normalization results: ");
Console.ResetColor();
foreach (var solvingNode in cycle)
{
solvingNode.PrintToConsole();
}
break;
}
case SortStatus.Sorted:
Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine($"Toposort results: ");
Console.ResetColor();
Console.WriteLine(string.Join("->", result.Order.Select(r => r.Name)));
Console.WriteLine("Refs:" + string.Join(",", result.Refs.Select(r => r.Name)));
return(result.Order.Union(result.Refs).ToArray());
}
}
}