a は 4 つまで。

; car_test

(define words '(((((ajax) binary) code) dump) emacs))

(display words)
(newline)
(newline)

(display (car words))
(newline)

(display (caar words))
(newline)

(display (caaar words))
(newline)

(display (caaaar words))
(newline)

(display (caaaaar words))
(newline)

%gosh car_test
(((((ajax) binary) code) dump) emacs)

((((ajax) binary) code) dump)
(((ajax) binary) code)
((ajax) binary)
(ajax)
gosh: "error": unbound variable: caaaaar
%

Gauche では、caaaar はあるけれど caaaaar は無い。a は最大 4 つまで。