X-Git-Url: https://git.distorted.org.uk/~mdw/lisp/blobdiff_plain/a721f2f26b71a60ee0aebb9c7d28f06c593ef2e4..fe0f07ea19b36ce1abc1ec305d0203323cbf2316:/collect.lisp

diff --git a/collect.lisp b/collect.lisp
index 946ba91..359780c 100644
--- a/collect.lisp
+++ b/collect.lisp
@@ -45,7 +45,7 @@
 	((atom vars) (setf vars (list vars))))
   `(let ,(mapcar (lambda (v) `(,v (make-collector))) vars)
      ,@body
-     (values ,@(mapcar (lambda (v) `(cdr ,v)) vars))))
+     (values ,@(mapcar (lambda (v) `(the list (cdr ,v))) vars))))
 
 (defmacro with-collection (vars collection &body body)
   "Collect items into lists VARS according to the form COLLECTION; then
@@ -71,4 +71,19 @@
      (setf (cdar ,name) ,x)
      (setf (car ,name) nil)))
 
+(defmacro collect-append (list &optional (name *collecting-anon-list-name*))
+  "Append LIST to the tail of `collecting' list NAME.  This obviously
+   involves copying LIST."
+  (with-gensyms item
+    `(dolist (,item ,list)
+       (collect ,item ,name))))
+
+(defmacro collect-nconc (list &optional (name *collecting-anon-list-name*))
+  "Attach LIST to the tail of `collecting' list NAME.  This will involve
+   destroying LIST if anything else gets collected afterwards."
+  (let*/gensyms list
+    `(when ,list
+       (setf (cdar ,name) ,list)
+       (setf (car ,name) (last ,list)))))
+
 ;;;----- That's all, folks --------------------------------------------------