/// <summary>
/// Subtracts the right operand from the left one.
/// </summary>
/// <param name="Left">Left operand.</param>
/// <param name="Right">Right operand.</param>
/// <param name="Node">Node performing the operation.</param>
/// <returns>Result</returns>
public static IElement EvaluateSubtraction(IElement Left, IElement Right, ScriptNode Node)
{
IGroupElement LE = Left as IGroupElement;
IGroupElement RE = Right as IGroupElement;
IElement Result;
IGroupElement Temp;
if (LE != null && RE != null)
{
Temp = RE.Negate();
if (Temp != null)
{
Result = LE.AddRight(Temp);
if (Result != null)
{
return(Result);
}
Result = Temp.AddLeft(LE);
if (Result != null)
{
return(Result);
}
}
}
if (Left.IsScalar)
{
if (Right.IsScalar)
{
ISet LeftSet = Left.AssociatedSet;
ISet RightSet = Right.AssociatedSet;
if (!LeftSet.Equals(RightSet))
{
if (!Expression.Upgrade(ref Left, ref LeftSet, ref Right, ref RightSet, Node))
{
throw new ScriptRuntimeException("Incompatible operands.", Node);
}
LE = Left as IGroupElement;
RE = Right as IGroupElement;
if (LE != null && RE != null)
{
Temp = RE.Negate();
if (Temp != null)
{
Result = LE.AddRight(Temp);
if (Result != null)
{
return(Result);
}
Result = Temp.AddLeft(LE);
if (Result != null)
{
return(Result);
}
}
}
}
throw new ScriptRuntimeException("Operands cannot be subtracted.", Node);
}
else
{
LinkedList <IElement> Elements = new LinkedList <IElement>();
foreach (IElement RightChild in Right.ChildElements)
{
Elements.AddLast(EvaluateSubtraction(Left, RightChild, Node));
}
return(Right.Encapsulate(Elements, Node));
}
}
else
{
if (Right.IsScalar)
{
LinkedList <IElement> Elements = new LinkedList <IElement>();
foreach (IElement LeftChild in Left.ChildElements)
{
Elements.AddLast(EvaluateSubtraction(LeftChild, Right, Node));
}
return(Left.Encapsulate(Elements, Node));
}
else
{
ICollection <IElement> LeftChildren = Left.ChildElements;
ICollection <IElement> RightChildren = Right.ChildElements;
if (LeftChildren.Count == RightChildren.Count)
{
LinkedList <IElement> Elements = new LinkedList <IElement>();
IEnumerator <IElement> eLeft = LeftChildren.GetEnumerator();
IEnumerator <IElement> eRight = RightChildren.GetEnumerator();
try
{
while (eLeft.MoveNext() && eRight.MoveNext())
{
Elements.AddLast(EvaluateSubtraction(eLeft.Current, eRight.Current, Node));
}
}
finally
{
eLeft.Dispose();
eRight.Dispose();
}
return(Left.Encapsulate(Elements, Node));
}
else
{
LinkedList <IElement> LeftResult = new LinkedList <IElement>();
foreach (IElement LeftChild in LeftChildren)
{
LinkedList <IElement> RightResult = new LinkedList <IElement>();
foreach (IElement RightChild in RightChildren)
{
RightResult.AddLast(EvaluateSubtraction(LeftChild, RightChild, Node));
}
LeftResult.AddLast(Right.Encapsulate(RightResult, Node));
}
return(Left.Encapsulate(LeftResult, Node));
}
}
}
}
/// <summary>
/// Subtracts the left group element from the right one: (-Left)+Right.
/// </summary>
/// <param name="Left">Left element.</param>
/// <param name="Right">Right element.</param>
/// <returns>Result, if understood, null otherwise.</returns>
public virtual IGroupElement LeftSubtract(IGroupElement Left, IGroupElement Right)
{
return(this.Add(Left.Negate(), Right) as IGroupElement);
}