public static void PrintTree(TreeNode tree, string spacing)
{
if (tree.Op != null)
{
Console.WriteLine(spacing + "+" + tree.Op);
PrintTree(tree.Left, spacing + " ");
PrintTree(tree.Right, spacing + " ");
}
else
Console.WriteLine(spacing + tree.Value);
}
public static void PrintTree(TreeNode tree)
{
PrintTree(tree, "");
}
public static int Execute(TreeNode root)
{
DynamicMethod method = new DynamicMethod("Exec_" + i++,
typeof(int),
new Type[] { },
typeof(Program).Module);
ILGenerator generator = method.GetILGenerator();
ILStack = new Stack<MathOpOrVal>();
BuildStack(ILStack, root);
while (ILStack.Count > 0)
{
MathOpOrVal mv = ILStack.Pop();
if (mv.Op != null)
{
switch (mv.Op)
{
case MathOp.Add:
Console.WriteLine("add");
generator.Emit(OpCodes.Add);
break;
case MathOp.Sub:
Console.WriteLine("sub");
generator.Emit(OpCodes.Sub);
break;
case MathOp.Mul:
Console.WriteLine("mul");
generator.Emit(OpCodes.Mul);
break;
case MathOp.Div:
Console.WriteLine("div");
generator.Emit(OpCodes.Div);
break;
}
}
else
{
Console.WriteLine("ldc " + mv.Value.Value);
generator.Emit(OpCodes.Ldc_I4, mv.Value.Value);
}
}
generator.Emit(OpCodes.Ret);
return (int)method.Invoke(null,
BindingFlags.ExactBinding,
null,
new object[] { },
null);
}
public TreeNode(MathOp op, TreeNode left, TreeNode right)
{
Op = op;
Left = left;
Right = right;
}
public static void BuildStack(Stack<MathOpOrVal> stack, TreeNode root)
{
if (root.Op != null)
{
MathOpOrVal mv = new MathOpOrVal(root.Op.Value);
stack.Push(mv);
BuildStack(stack, root.Right);
BuildStack(stack, root.Left);
}
else
{
MathOpOrVal mv = new MathOpOrVal(root.Value.Value);
stack.Push(mv);
}
}
