TAILP

[jscl.git] / src / list.lisp

diff --git a/src/list.lisp b/src/list.lisp
index fd9e0bd..173dedf 100644 (file)
--- a/src/list.lisp
+++ b/src/list.lisp
@@ -37,11 +37,17 @@
 
 (defun cdr (x) (cdr x))
 
-(defun first (x) (car x))
-(defun second (x) (cadr x))
-(defun third (x) (caddr x))
-(defun fourth (x) (cadddr x))
-(defun rest (x) (cdr x))
+(defun first   (x) (car    x))
+(defun second  (x) (cadr   x))
+(defun third   (x) (caddr  x))
+(defun fourth  (x) (cadddr x))
+(defun fifth   (x) (car    (cddddr x)))
+(defun sixth   (x) (cadr   (cddddr x)))
+(defun seventh (x) (caddr  (cddddr x)))
+(defun eighth  (x) (cadddr (cddddr x)))
+(defun ninth   (x) (car  (cddddr (cddddr x))))
+(defun tenth   (x) (cadr (cddddr (cddddr x))))
+(defun rest    (x) (cdr x))
 
 (defun list (&rest args)
   args)
@@ -110,6 +116,12 @@
          (tree-equal (car tree1) (car tree2) :test test)
          (tree-equal (cdr tree1) (cdr tree2) :test test))))
 
+(defun tailp (object list)
+  (do ((tail list (cdr tail)))
+    ((atom tail) (eq object tail))
+    (when (eql tail object)
+      (return-from tailp t))))
+
 (defun subst (new old tree &key (key #'identity) (test #'eql))
   (cond 
     ((funcall test (funcall key tree) (funcall key old))