`car', `cdr', `cons', `append', `reverse', `length'
---------------------------------------------------

car(LIST)
     :: Ǥʤ LIST Ƭ.
cdr(LIST)
     :: Ǥʤ LIST ƬǤꥹ.
cons(OBJ,LIST)
     :: LIST Ƭ OBJ դäꥹ.
append(LIST1,LIST2)
     :: LIST1  LIST2 򤳤ν 1 Ĥˤꥹ.
reverse(LIST)
     :: LIST սˤꥹ.
length(LIST)
     :: LIST Ĺ.

RETURN
     `car()' : Ǥ, `cdr()', `cons()', `append()', `reverse()' : ꥹ
     , `length()' : 
LIST,LIST1,LIST2
     ꥹ
OBJ
     Ǥ

   * ꥹȤ [OBJ1,OBJ2,...] ɽ. OBJ1 ƬǤǤ.
   * `car()' , Ǥʤ LIST ƬǤϤ. ꥹȤϤ
     줿, ꥹȤϤ.
   * `cdr()' , Ǥʤ LIST ƬǤꥹȤϤ
     . ꥹȤϤ줿, ꥹȤϤ.
   * `cons()' , LIST Ƭ OBJ դäꥹȤϤ.
   * `append()' , LIST1 Ǥ LIST2 Τ٤ƤǤ礵
      [LIST1 Ǥ¤,LIST2 Ǥ¤] Ϥ.
   * `reverse()' , LIST սˤꥹȤϤ.
   * `length()' , LIST ĹϤ. ٥ȥڤӹǤθ
     , `size()' Ѥ.
   * ꥹȤɤ߽ФѤ, ǤؤϤǤʤ.
   * ꥹȤ N ܤǤμФ, `cdr()'  N ŬѤ 
     `car()' ŬѤ뤳ȤˤǽǤ뤬, ˡȤ, ٥ȥ, 
     ʤɤƱ, ǥå `[N]' դ뤳Ȥˤ
     ФȤǤ. , ƥǤ, ºݤ˥ݥ󥿤 
     N 󤿤ɤΤ, ǤۤɼФ˻֤.
   * `cdr()' Ͽʤ, `append()' , ºݤˤ 1 
     ΥꥹȤĹ `cons()' η֤Ȥʤ뤿,  1 
     ΥꥹȤĹˤ¿Υ񤹤뤳Ȥˤʤ. 
     `reverse()' ˴ؤƤƱͤǤ.

     [0] L = [[1,2,3],4,[5,6]];
     [[1,2,3],4,[5,6]]
     [1] car(L);
     [1,2,3]
     [2] cdr(L);
     [4,[5,6]]
     [3] cons(x*y,L);
     [y*x,[1,2,3],4,[5,6]]
     [4] append([a,b,c],[d]);
     [a,b,c,d]
     [5] reverse([a,b,c,d]);
     [d,c,b,a]
     [6] length(L);
     3
     [7] L[2][0];
     5

