Navigating syntax trees

Every node in the syntax tree implements ITreeNode, as well as interfaces that better reflect the node's type and purpose, such as IComment or IMethodDeclaration. The ITreeNode interface includes members pertinent to navigating and processing the tree. These members are shown below (other members removed for brevity):

public interface ITreeNode
{
  ITreeNode Parent { get; }
  ITreeNode FirstChild { get; }
  ITreeNode LastChild  { get; }
  ITreeNode NextSibling { get; }
  ITreeNode PrevSibling { get; }

  // [...snip...]
}

There are several ways of navigating the tree.

Manually walking the tree, using the interface members shown above. This is the least recommended, requiring boilerplate tree walking code that is time consuming and easy to get wrong.
Use the TreeNodeExtensions helper methods to manually walk the tree.
Use strongly typed navigation, using accessors on derived ITreeNode implementations, and the strongly typed "navigator" classes.
Process the tree using the visitor pattern or the IRecursiveElementProcessor set of classes.
Finding child or parent nodes of a specific type.

Last modified: 20 April 2023