(doc-group list  «Working with lists.») (defdoc NIL  «An empty list.  Can be used as the opposite of T in boolean   expressions.»  :doc-example  «(not NIL)   ; ↳ T»  :doc-example  «(if NIL 'yes 'no)   ; ↳ no»  :doc-example  «(car NIL)   ; ↳ NIL»  :doc-example  «(cdr NIL)   ; ↳ NIL»  :doc-group list  :doc-see T) (defdoc (length seq)  «Return the length of the sequence.    String's length is measured in UTF-8 code points.  For tables the number   of key-value pairs is returned.    Note: for circular lists the result is `NIL`.  A type error exception is   thrown on improper lists, which are not considered valid sequences.»  :doc-example  «(length "абвгд")   ; ↳ 5»  :doc-example  «(length #(abc 123))   ; ↳ 2»  :doc-example  «(length #table(0 a  1 b  2 c))   ; ↳ 3»  :doc-example  «(length (arr 'u32 1 2 3 4))   ; ↳ 4»  :doc-example  «(length '(1 2 3 4 5))   ; ↳ 5»  :doc-example  «(length '(1 2 3 4 . 5)) ; improper list   ; ‼ type error: expected cons, got fixnum: 5»  :doc-example  «(length '#0=(1 . #0#)) ; circular list   ; ↳ NIL»  :doc-group array  :doc-group list  :doc-group table  :doc-see proper-list?) (defdoc (assq key lst)  «Return a pair of a matching key and the associated value, or `NIL` if   none matched.  Keys are compared using `eq?`.»  :doc-group list  :doc-see assoc  :doc-see assv) (defdoc (memq item lst)  «Return the tail of a list beginning with the item, or `NIL` otherwise.   List elements are compared to the `item` using `eq?`.»  :doc-group list  :doc-see member  :doc-see memv)