SOURCE_FILE
  MACRO_DEF
    MACRO_KW "macro"
    WHITESPACE " "
    NAME
      IDENT "m"
    WHITESPACE " "
    TOKEN_TREE
      L_CURLY "{"
      WHITESPACE " "
      TOKEN_TREE
        L_PAREN "("
        DOLLAR "$"
        IDENT "i"
        COLON ":"
        IDENT "ident"
        R_PAREN ")"
      WHITESPACE " "
      EQ "="
      R_ANGLE ">"
      WHITESPACE " "
      TOKEN_TREE
        L_CURLY "{"
        R_CURLY "}"
      WHITESPACE " "
      R_CURLY "}"
  WHITESPACE "\n"