/// <summary>
/// Merge two nodes. Both of them become equiualent.
///
/// In complex situation, 'secondary' node becomes reference to 'main' node, if it is possible
/// </summary>
public static void MergeInplace(TicNode main, TicNode secondary)
{
if (main == secondary)
{
return;
}
if (main.State is StateRefTo)
{
var nonreferenceMain = main.GetNonReference();
var nonreferenceSecondary = secondary.GetNonReference();
MergeInplace(nonreferenceMain, nonreferenceSecondary);
return;
}
if (secondary.GetNonReference() == main)
{
return;
}
var res = GetMergedStateOrNull(main.State, secondary.State);
if (res == null)
{
throw TicErrors.CannotMerge(main, secondary);
}
main.State = res;
if (res is ITypeState t && t.IsSolved)
{
secondary.State = res;
return;
}
main.AddAncestors(secondary.Ancestors.Where(a => a != main));
secondary.ClearAncestors();
secondary.State = new StateRefTo(main);
}
public TicNode GetNonReferenceMergedOrNull(TicNode node)
{
if (node.VisitMark == RefVisitedMark)
{
return(null);
}
_refRoute = new Stack <TicNode>();
var nonReference = GetNonReferenceNodeOrNull(node);
if (nonReference != null)
{
return(nonReference);
}
// ref cycle found!
// the node becomes one non reference node with no constrains
node.State = new ConstrainsState();
foreach (var refNode in _refRoute)
{
if (refNode == node)
{
continue;
}
if (refNode.VisitMark == RefVisitedMark)
{
continue;
}
node.AddAncestors(refNode.Ancestors);
refNode.ClearAncestors();
refNode.VisitMark = RefVisitedMark;
if (refNode.IsMemberOfAnything)
{
refNode.IsMemberOfAnything = false;
}
}
return(node);
}