internal static SetNode Subtract(SetNode A, SetNode B)
{
if (A.Type == SetNode.NodeType.OPERATOR || B.Type == SetNode.NodeType.OPERATOR)
{
return(A - B);
}
var(goodAPieces, badAPieces) = GatherEvaluablePieces(A as Set);
var(goodBPieces, badBPieces) = GatherEvaluablePieces(B as Set);
var newGoodPieces = new List <Piece>();
newGoodPieces.AddRange(goodAPieces);
foreach (var goodB in goodBPieces)
{
var newNewGoodPieces = new List <Piece>();
foreach (var newGoodPiece in newGoodPieces)
{
newNewGoodPieces.AddRange(PieceFunctions.Subtract(newGoodPiece, goodB));
}
newGoodPieces = newNewGoodPieces;
}
newGoodPieces.AddRange(badAPieces);
var newSet = new Set {
Pieces = newGoodPieces
};
if (badBPieces.Count == 0)
{
return(newSet);
}
else
{
return(new OperatorSet(OperatorSet.OperatorType.COMPLEMENT, newSet, new Set {
Pieces = badBPieces
}));
}
}
public static SetNode Invert(SetNode A)
{
if (A.Type == SetNode.NodeType.OPERATOR)
{
return(new OperatorSet(OperatorSet.OperatorType.INVERSION, A));
}
var(goodAPieces, badAPieces) = GatherEvaluablePieces(A as Set);
var remainders = new List <Piece> {
Piece.CreateUniverse()
};
foreach (var good in goodAPieces)
{
var newRemainders = new List <Piece>();
foreach (var rem in remainders)
{
newRemainders.AddRange(PieceFunctions.Subtract(rem, good));
}
remainders = newRemainders;
}
var newSet = new Set {
Pieces = remainders
};
if (badAPieces.Count == 0)
{
return(newSet);
}
else
{
return(new OperatorSet(OperatorSet.OperatorType.COMPLEMENT, newSet, new Set {
Pieces = badAPieces
}));
}
}