[cl-utilities-cvs] CVS update: cl-utilities/once-only.lisp

[Peter Scott]

Update of /project/cl-utilities/cvsroot/cl-utilities
In directory common-lisp.net:/tmp/cvs-serv3083

Modified Files:
	once-only.lisp 
Log Message:
Factored out error checking

Date: Thu May 26 21:09:05 2005
Author: pscott

Index: cl-utilities/once-only.lisp
diff -u cl-utilities/once-only.lisp:1.1.1.1 cl-utilities/once-only.lisp:1.2
--- cl-utilities/once-only.lisp:1.1.1.1	Mon May  9 23:26:29 2005
+++ cl-utilities/once-only.lisp	Thu May 26 21:09:05 2005
@@ -7,11 +7,18 @@
 
 (in-package :cl-utilities)
 
-(defmacro once-only ((&rest names) &body body)
-  ;; Check that all of the NAMES are symbols. If not, raise an error.
+(defun check-once-only-names (names)
+  "Check that all of the NAMES are symbols. If not, raise an error."
+  ;; This only raises an error for the first non-symbol argument
+  ;; found. While this won't report multiple errors, it is probably
+  ;; more convenient to only report one.
   (let ((bad-name (find-if-not #'symbolp names)))
     (when bad-name
-      (error "ONCE-ONLY expected a symbol but got ~S" bad-name)))
+      (error "ONCE-ONLY expected a symbol but got ~S" bad-name))))
+
+(defmacro once-only (names &body body)
+  ;; Check the NAMES list for validity.
+  (check-once-only-names names)
   ;; Do not touch this code unless you really know what you're doing.
   (let ((gensyms (loop for name in names collect (gensym (string name)))))
     `(let (,@(loop for g in gensyms