/// <summary>
/// Resolves a single GotoItem by traversing up the tree from the given
/// root. Throws an exception if the label cannot be found.
/// </summary>
/// <param name="root">The node to start the search.</param>
/// <param name="item">The item to resolve.</param>
static void ResolveGoto(TreeNode/*!*/ root, GotoItem/*!*/ item)
{
do
{
foreach (var label in root.Labels)
{
if (label.Name == item.Name)
{
item.Target = label;
return;
}
}
}
// break statements can pass through local definitions
while ((item.Name != "<break>" || !root.IsFunction) &&
(item.Name == "<break>" || root.Passable) &&
(root = root.Parrent) != null);
throw new SyntaxException(string.Format(Resources.LabelNotFound, item.Name), item.Debug);
}
/// <summary>
/// Called when the item is a goto item.
/// </summary>
/// <param name="target">The object that was passed to IParseItem.Visit.</param>
/// <returns>The passed target or a modification of it.</returns>
/// <exception cref="System.ArgumentNullException">If target is null.</exception>
public IParseItem Visit(GotoItem target)
{
if (target == null)
throw new ArgumentNullException("target");
tree.DefineGoto(target);
return target;
}
/// <summary>
/// Defines a new GotoItem in the current block.
/// </summary>
/// <param name="item">The item to define.</param>
public void DefineGoto(GotoItem/*!*/ item)
{
cur.GotoItems.Add(item);
}
/// <summary>
/// Called when the item is a goto item.
/// </summary>
/// <param name="target">The object that was passed to IParseItem.Visit.</param>
/// <returns>The passed target or a modification of it.</returns>
/// <exception cref="System.ArgumentNullException">If target is null.</exception>
public IParseItem Visit(GotoItem target)
{
if (target == null)
throw new ArgumentNullException("target");
if (target.Target == null)
throw new InvalidOperationException(Resources.ErrorResolveLabel);
compiler.CurrentGenerator.Emit(OpCodes.Br, (Label)target.Target.UserData);
return target;
}
