SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "f"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE " "
        BLOCK_EXPR
          UNSAFE_KW "unsafe"
          WHITESPACE " "
          STMT_LIST
            L_CURLY "{"
            WHITESPACE " "
            R_CURLY "}"
        WHITESPACE " "
        R_CURLY "}"
  WHITESPACE "\n"
