From: David Vázquez <davazp@gmail.com>
Date: Thu, 25 Apr 2013 22:01:15 +0000 (+0100)
Subject: INCF and DECF work on proper places
X-Git-Url: http://repo.macrolet.net/gitweb/?a=commitdiff_plain;h=b5ea0102bc06080b0ad3d0fa3bf11175c21a3380;p=jscl.git

INCF and DECF work on proper places
---

diff --git a/src/boot.lisp b/src/boot.lisp
index d57fa0b..0fc7a40 100644
--- a/src/boot.lisp
+++ b/src/boot.lisp
@@ -154,11 +154,25 @@
 
 ;; Basic macros
 
-(defmacro incf (x &optional (delta 1))
-  `(setq ,x (+ ,x ,delta)))
+(defmacro incf (place &optional (delta 1))
+  (multiple-value-bind (dummies vals newval setter getter)
+      (get-setf-expansion place)
+    (let ((d (gensym)))
+      `(let* (,@(mapcar #'list dummies vals)
+              (,d ,delta)
+                (,(car newval) (+ ,getter ,d))
+                ,@(cdr newval))
+         ,setter))))
 
-(defmacro decf (x &optional (delta 1))
-  `(setq ,x (- ,x ,delta)))
+(defmacro decf (place &optional (delta 1))
+  (multiple-value-bind (dummies vals newval setter getter)
+      (get-setf-expansion place)
+    (let ((d (gensym)))
+      `(let* (,@(mapcar #'list dummies vals)
+              (,d ,delta)
+              (,(car newval) (- ,getter ,d))
+              ,@(cdr newval))
+         ,setter))))
 
 (defmacro push (x place)
   (multiple-value-bind (dummies vals newval setter getter)