;;; -*-lisp-*-
;;;
-;;; $Id$
-;;;
;;; Collecting things into lists
;;;
;;; (c) 2005 Straylight/Edgeware
;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
(defpackage #:collect
- (:use #:common-lisp #:mdw.base)
- (:export #:make-collector #:collected
- #:collecting #:with-collection
- #:collect #:collect-tail
- #:collect-append #:collect-nconc))
+ (:use #:common-lisp #:mdw.base))
(in-package collect)
(eval-when (:compile-toplevel :load-toplevel)
(defvar *collecting-anon-list-name* (gensym)
"The default name for anonymous `collecting' lists."))
+(export 'make-collector)
(defun make-collector (&optional list)
"Return a new collector object whose initial contents is LIST. Note that
LIST will be destroyed if anything else is collected."
(let ((head (cons nil list)))
(setf (car head) (if list (last list) head))))
+(export 'collected)
(defmacro collected (&optional (name *collecting-anon-list-name*))
"Return the current list collected into the collector NAME (or
*collecting-anon-list-name* by default)."
`(the list (cdr ,name)))
+(export 'collecting)
(defmacro collecting (vars &body body)
"Collect items into lists. The VARS are a list of collection variables --
their values are unspecified, except that they may be passed to `collect'
- and `collect-tail' If VARS is empty then *collecting-anon-list-name* is
+ and `collect-tail'. If VARS is empty then *collecting-anon-list-name* is
used. VARS may be an atom instead of a singleton list. The form produces
multiple values, one for each list constructed."
(cond ((null vars) (setf vars (list *collecting-anon-list-name*)))
,@body
(values ,@(mapcar (lambda (v) `(collected ,v)) vars))))
+(export 'with-collection)
(defmacro with-collection (vars collection &body body)
"Collect items into lists VARS according to the form COLLECTION; then
evaluate BODY with VARS bound to those lists."
`(multiple-value-bind
- ,(listify vars)
+ ,(listify vars)
(collecting ,vars ,collection)
,@body))
+(export 'collect)
(defmacro collect (x &optional (name *collecting-anon-list-name*))
"Add item X to the `collecting' list NAME (or *collecting-anon-list-name*
by default)."
(setf (cdar ,name) ,new)
(setf (car ,name) ,new))))
+(export 'collect-tail)
(defmacro collect-tail (x &optional (name *collecting-anon-list-name*))
"Make item X be the tail of `collecting' list NAME (or
*collecting-anon-list-name* by default). It is an error to continue
(setf (cdar ,name) ,x)
(setf (car ,name) nil)))
+(export 'collect-append)
(defmacro collect-append (list &optional (name *collecting-anon-list-name*))
"Append LIST to the tail of `collecting' list NAME. This obviously
involves copying LIST."
`(dolist (,item ,list)
(collect ,item ,name))))
+(export 'collect-nconc)
(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."