==================
attribute with literal
==================

foo = "bar"

---

(config_file
  (body
    (attribute
      (identifier)
      (expression
        (expr_term
          (literal_value
            (string_lit)))))))

==================
attribute with variable
==================

foo = bar

---

(config_file
  (body
    (attribute
      (identifier)
      (expression
        (expr_term
          (variable_expr
            (identifier)))))))