Code Modification

// Renaming a named code object is trivial - just assign a new name, and all resolved references will
// automatically make use of the new name (for name changes, it's obviously very important that all
// symbolic references are resolved first).  Code objects have various other properties which can also
// be directly assigned.  Some code objects have direct children code objects (such as the various parts
// of a For loop) which can be directly assigned to LocalDecls or Expressions.  Many (such as all
// BlockStatements) have a Body which is a collection of child code objects which can be manipulated
// using methods such as Add(), Remove(), and Insert().

// Here are some examples using a small code fragment:
const string fragment =
    "/// <see cref=\"OldClass\"/>\n" +
    "class OldClass\n" +
    "{\n" +
    "    public OldClass(int arg)\n" +
    "    { }\n" +
    "    \n" +
    "    private void ToBeDeletedMethod()\n" +
    "    { }\n" +
    "    \n" +
    "    /// <param name=\"oldArg\">The argument.</param>\n" +
    "    private void Method(int oldArg = -1)\n" +
    "    {\n" +
    "        OldClass x = new OldClass(oldArg);\n" +
    "        for (int i = oldArg; i < 10; ++i)\n" +
    "            x.Method(oldArg);\n" +
    "    }\n" +
    "}\n";
CodeUnit codeUnit = CodeUnit.LoadFragment(fragment, "Fragment");
if (codeUnit != null)
{
    var classDecl = codeUnit.FindFirst<ClassDecl>("OldClass");
    if (classDecl != null)
    {
        // Rename 'OldClass' to 'NewClass' and change it to 'public'
        classDecl.Name = "NewClass";
        classDecl.IsPublic = true;

        var methodDecl = classDecl.FindFirst<MethodDecl>("Method");
        if (methodDecl != null)
        {
            // Change 'Method' to 'public', and change its return type from 'void' to 'int'
            methodDecl.IsPublic = true;
            methodDecl.ReturnType = typeof(int);

            // Rename the parameter of 'Method' from 'oldArg' to 'newArg', change its type from 'int' to 'long',
            // and change its initialization from '-1' to '0'.
            var parameterDecl = methodDecl.Parameters[0];
            parameterDecl.Name = "newArg";
            parameterDecl.Type = typeof(long);
            parameterDecl.Initialization = 0;
        }

        // Insert a new method after the constructor
        classDecl.Insert(1, new MethodDecl("InsertedMethod", typeof(void)));

        // Remove a method
        var toBeDeleted = classDecl.FindFirst<MethodDecl>("ToBeDeletedMethod");
        if (toBeDeleted != null)
            classDecl.Remove(toBeDeleted);
    }

    // Insert an enum into the CodeUnit before the class
    codeUnit.Insert(0, new EnumDecl("Enum") { MemberDecls = { new EnumMemberDecl("One"), new EnumMemberDecl("Two") } });

    // Display the modified code
    Log.WriteLine(codeUnit.AsString());
}