From eb090229ee1cd6a2e9976670532e505eba595036 Mon Sep 17 00:00:00 2001
From: Juan Jose Garcia Ripoll <jjgarcia@users.sourceforge.net>
Date: Thu, 20 May 2010 21:57:33 +0200
Subject: [PATCH] The sequence iteration macros allow specifying the name of
 the index variable

---
 src/lsp/seqmacros.lsp | 45 +++++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/src/lsp/seqmacros.lsp b/src/lsp/seqmacros.lsp
index 15813bbd5..5033ca6a1 100644
--- a/src/lsp/seqmacros.lsp
+++ b/src/lsp/seqmacros.lsp
@@ -57,50 +57,53 @@
 (defmacro reckless (&body body)
   `(locally (declare (optimize (safety 0) (speed 3) (debug 0))) ,@body))
 
-(defmacro do-vector ((elt vector start end &key from-end output) &body body)
-  (with-unique-names (%vector %i %count)
+(defmacro do-vector ((elt vector start end
+                      &key from-end output (index (gensym)))
+                     &body body)
+  (with-unique-names (%vector %count)
     (if from-end
 	`(do* ((,%vector ,vector)
-	       (,%i ,end)
+	       (,index ,end)
 	       (,%count ,start))
-	      ((= ,%i ,%count) ,output)
-	   (declare (fixnum ,%i ,%count)
+	      ((= ,index ,%count) ,output)
+	   (declare (fixnum ,index ,%count)
 		    (vector ,%vector))
-	   (let ((,elt (reckless (aref ,%vector (setf ,%i (1- ,%i))))))
+	   (let ((,elt (reckless (aref ,%vector (setf ,index (1- ,index))))))
 	     ,@body))
 	`(do* ((,%vector ,vector)
-	       (,%i ,start (1+ ,%i))
+	       (,index ,start (1+ ,index))
 	       (,%count ,end))
-	      ((= ,%i ,%count) ,output)
-	   (declare (fixnum ,%i ,%count)
+	      ((= ,index ,%count) ,output)
+	   (declare (fixnum ,index ,%count)
 		    (vector ,%vector))
-	   (let ((,elt (reckless (aref ,%vector ,%i))))
+	   (let ((,elt (reckless (aref ,%vector ,index))))
 	     ,@body)))))
 
-(defmacro do-sublist ((elt list start end &key output) &body body)
-  (with-unique-names (%sublist %i %count)
-    `(do* ((,%i ,start)
-	   (,%sublist (nthcdr ,%i ,list) (cdr ,%sublist))
-	   (,%count (- ,end ,%i) (1- ,%count)))
+(defmacro do-sublist ((elt list start end &key output (index (gensym))) &body body)
+  (with-unique-names (%sublist %count)
+    `(do* ((,index ,start (1+ ,index))
+	   (,%sublist (nthcdr ,index ,list) (cdr ,%sublist))
+	   (,%count (- ,end ,index) (1- ,%count)))
 	  ((<= ,%count 0) ,output)
-       (declare (fixnum ,%i ,%count)
+       (declare (fixnum ,index ,%count)
 		(cons ,%sublist))
        (let ((,elt (car ,%sublist)))
 	 ,@body))))
 
-(defmacro do-sequence ((elt sequence start end &key output specialize) &body body)
+(defmacro do-sequence ((elt sequence start end &key (index (gensym)) output specialize)
+		       &body body)
   (if specialize
       (with-unique-names (%sequence)
 	`(let ((,%sequence ,sequence))
 	   (if (listp ,%sequence)
-	       (do-sublist (,elt ,%sequence ,start ,end :output ,output)
+	       (do-sublist (,elt ,%sequence ,start ,end :output ,output :index ,index)
 		 ,@body)
-	       (do-vector (,elt ,%sequence ,start ,end :output ,output)
+	       (do-vector (,elt ,%sequence ,start ,end :output ,output :index ,index)
 		 ,@body))))
       (with-unique-names (%sequence %start %i %count)
 	`(do* ((,%sequence ,sequence)
-	       (,%start ,start)
-	       (,%i (make-seq-iterator ,%sequence ,%start)
+	       (,index ,start (1+ ,index))
+	       (,%i (make-seq-iterator ,%sequence ,index)
 		    (seq-iterator-next ,%sequence ,%i))
 	       (,%count (- ,end ,start) (1- ,%count)))
 	      ((or (null ,%i) (not (plusp ,%count))) ,output)