YAML's syntax is similar to other high-level languages and can simply represent data structures such as lists, hash tables, and scalars. It uses indentation with whitespace and relies heavily on visual appearance, making it particularly suitable for representing or editing data structures, various configuration files, debugging dumps, and document outlines (for example, many email header formats are very close to YAML). Although it is particularly suited for representing hierarchical model data structures, it also has sophisticated syntax to represent relational model data. Since YAML uses whitespace and line breaks to separate data, it is especially well-suited for manipulation with tools like grep, Python, Perl, and Ruby. One of its most accessible features is its clever avoidance of various enclosing symbols, such as quotation marks and parentheses, which can become complex and difficult to decipher in nested structures.