SOURCE_FILE
  TYPE_ALIAS
    TYPE_KW "type"
    WHITESPACE " "
    NAME
      IDENT "F"
    WHITESPACE " "
    EQ "="
    WHITESPACE " "
    FN_PTR_TYPE
      FN_KW "fn"
      PARAM_LIST
        L_PAREN "("
        R_PAREN ")"
      WHITESPACE " "
      RET_TYPE
        THIN_ARROW "->"
        WHITESPACE " "
        TUPLE_TYPE
          L_PAREN "("
          R_PAREN ")"
    SEMICOLON ";"
  WHITESPACE "\n"