Complete SUBST support with :test-not keyword parameter, error checking and tests

diff --git a/src/list.lisp b/src/list.lisp
index 9a445db..f7e15ec 100644 (file)
--- a/src/list.lisp
+++ b/src/list.lisp
@@ -113,6 +113,17 @@
                    (cons (s (car x)) (s (cdr x)))))))
     (s tree)))
 
+(defun subst (new old tree &key key (test #'eql testp) (test-not #'eql test-not-p))
+  (when (and testp test-not-p)
+    (error "Both test and test-not are set"))
+  (labels ((s (x)
+             (let ((key-val (if key (funcall key x) x)))
+               (cond
+                 ((funcall (if test-not-p test-not test) key-val old) new)
+                 ((atom x) x)
+                 (t (cons (s (car x)) (s (cdr x))))))))
+    (s tree)))
+
 (defun copy-list (x)
   (mapcar #'identity x))
 
@@ -135,15 +146,6 @@
     (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))
-     new) 
-    ((consp tree)
-     (cons (subst new old (car tree) :key key :test test)
-           (subst new old (cdr tree) :key key :test test))) 
-    (t tree)))
-
 (defmacro pop (place)
   (multiple-value-bind (dummies vals newval setter getter)
     (get-setf-expansion place)

diff --git a/tests/list.lisp b/tests/list.lisp
index f002e1e..77b93c6 100644 (file)
--- a/tests/list.lisp
+++ b/tests/list.lisp
@@ -93,6 +93,22 @@
   (test (equal (sublis '(("two" . 2)) tree2 :test 'equal)
                '("one" ("one" 2) (("one" "Two" "three"))))))
 
+;; SUBST
+(let ((tree1 '(1 (1 2) (1 2 3) (1 2 3 4))))
+  (test (equal (subst "two" 2 tree1) '(1 (1 "two") (1 "two" 3) (1 "two" 3 4))))
+  (test (equal (subst "five" 5 tree1) '(1 (1 2) (1 2 3) (1 2 3 4))))
+  (test (not (eq tree1 (subst "five" 5 tree1)))) ; Implementation dependent
+  (test (equal tree1 '(1 (1 2) (1 2 3) (1 2 3 4)))))
+(test (equal (subst 'tempest 'hurricane
+                    '(shakespeare wrote (the hurricane)))
+             '(SHAKESPEARE WROTE (THE TEMPEST))))
+(test (equal (subst 'foo 'nil '(shakespeare wrote (twelfth night)))
+             '(SHAKESPEARE WROTE (TWELFTH NIGHT . FOO) . FOO)))
+(test (equal (subst '(a . cons) '(old . pair)
+                    '((old . spice) ((old . shoes) old . pair) (old . pair))
+                    :test #'equal)
+             '((OLD . SPICE) ((OLD . SHOES) A . CONS) (A . CONS))))
+
 ; COPY-TREE
 (test (let* ((foo (list '(1 2) '(3 4)))
              (bar (copy-tree foo)))
@@ -169,8 +185,6 @@
 (test (not (intersection '(1 2 3) '(4 5 6))))
 (test (equal (intersection '((1) (2)) '((2) (3)) :test #'equal) '((2))))
 
-; SUBST
-
 ; POP
 (test (let* ((foo '(1 2 3))
              (bar (pop foo)))