================================================================================
simple conditional expression
================================================================================

foo = predicate() ? 1: 2

--------------------------------------------------------------------------------

(config_file
  (body
    (attribute
      (identifier)
      (expression
        (conditional
          (expression
            (function_call
              (identifier)))
          (expression
            (literal_value
              (numeric_lit)))
          (expression
            (literal_value
              (numeric_lit))))))))