(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 used.
-VARS may be an atom instead of a singleton list. The form produces multiple
-values, one for each list constructed."
+ 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
+ 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*)))
((atom vars) (setf vars (list vars))))
`(let ,(mapcar (lambda (v) `(,v (make-collector))) vars)
(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."
+ evaluate BODY with VARS bound to those lists."
`(multiple-value-bind
- ,(listify vars)
+ ,(listify vars)
(collecting ,vars ,collection)
,@body))
(defmacro collect (x &optional (name *collecting-anon-list-name*))
"Add item X to the `collecting' list NAME (or *collecting-anon-list-name*
-by default)."
+ by default)."
(with-gensyms tmp
`(let ((,tmp (cons ,x nil)))
(setf (cddr ,name) ,tmp)
(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 trying
-to add stuff to the list."
+ *collecting-anon-list-name* by default). It is an error to continue
+ trying to add stuff to the list."
`(progn
(setf (cddr ,name) ,x)
(setf (cdr ,name) nil)))