You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: gotype.go
    path of file: ./repos/gomacro/go/types
    
    the code of the file until where you have to start completion: // Copyright 2011 The Go Authors. All rights reserved.
// Use of this source
    
func getPkgFiles(args []string) ([]*ast.File, error) {
	if len(args) == 0 {
		// stdin
		file, err := parseStdin()
		if err != nil {
			return nil, err
		}
		return []*ast.File{file}, nil
	}

	if len(args) == 1 {
		// possibly a directory
		path := args[0]
		info, err := os.Stat(path)
		if err != nil {
			return nil, err
		}
		if info.IsDir() {
			return parseDir(path)
		}
	}

	// list of files
	return parseFiles("", args)
}