return buf.String()
}

func TestCommentMap(t *testing.T) {
	fset := token.NewFileSet()
	f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
	if err != nil {
		t.Fatal(err)
	}
	cmap := NewCommentMap(fset, f, f.Comments)

	// very correct association of comments
	for n, list := range cmap {
		key := fmt.Sprintf("%2d: %T", fset.Position(n.Pos()).Line, n)
		got := ctext(list)
		want := res[key]

//     via the previous rules
//
// NewCommentMap tries to associate a comment group to the "largest"
// node possible: For instance, if the comment is a line comment
// trailing an assignment, the comment is associated with the entire
// assignment rather than just the last operand in the assignment.
func NewCommentMap(fset *token.FileSet, node Node, comments []*CommentGroup) CommentMap {

	if err != nil {
		panic(err)
	}

	// Create an ast.CommentMap from the ast.File's comments.
	// This helps keeping the association between comments
	// and AST nodes.
	cmap := ast.NewCommentMap(fset, f, f.Comments)

	// Remove the first variable declaration from the list of declarations.
	for i, decl := range f.Decls {
		if gen, ok := decl.(*ast.GenDecl); ok && gen.Tok == token.VAR {

	}

}

func pvagenerate(t *testing.T) string {
	var fset token.FileSet
	f, err := parser.ParseFile(&fset, "./dwarf.go", nil, parser.ParseComments)
	if err != nil {
		t.Fatal(err)
	}
	cm := ast.NewCommentMap(&fset, f, f.Comments)
	abbrevs := make(map[string]int)
	funcs := map[string]ast.Stmt{}
	for _, decl := range f.Decls {
		decl, ok := decl.(*ast.FuncDecl)
		if !ok || decl.Body == nil {
			continue
		}

	fmt.Println()
}
*/

// rewriteFile applies the rewrite rule 'pattern -> replace' to an entire file.
func rewriteFile(fileSet *token.FileSet, pattern, replace ast.Expr, p *ast.File) *ast.File {
	cmap := ast.NewCommentMap(fileSet, p, p.Comments)
	m := make(map[string]reflect.Value)
	pat := reflect.ValueOf(pattern)
	repl := reflect.ValueOf(replace)

	var rewriteVal func(val reflect.Value) reflect.Value

		{"Lbl", Const, 0},
		{"MapType", Type, 0},
		{"MapType.Key", Field, 0},
		{"MapType.Map", Field, 0},
		{"MapType.Value", Field, 0},
		{"MergeMode", Type, 0},
		{"MergePackageFiles", Func, 0},
		{"NewCommentMap", Func, 1},
		{"NewIdent", Func, 0},
		{"NewObj", Func, 0},
		{"NewPackage", Func, 0},
		{"NewScope", Func, 0},
		{"Node", Type, 0},
		{"NotNilFilter", Func, 0},
		{"ObjKind", Type, 0},

pkg go/ast, const Fun = 5
pkg go/ast, const Lbl = 6
pkg go/ast, const Pkg = 1
pkg go/ast, const RECV = 2
pkg go/ast, const SEND = 1
pkg go/ast, const Typ = 3
pkg go/ast, const Var = 4
pkg go/ast, func NewCommentMap(*token.FileSet, Node, []*CommentGroup) CommentMap
pkg go/ast, method (CommentMap) Comments() []*CommentGroup
pkg go/ast, method (CommentMap) Filter(Node) CommentMap
pkg go/ast, method (CommentMap) String() string