Dear Alexandrians,
"Tobias C. Rittweiler" tcr@freebits.de writes:
I hope that was why you Alexandrians ignored me . . .
No ignoring, it's just the wrong phase of the moon right now.
Please consider the cdr-assoc again. It could be improved, which improvements would encourage you to view it more favourably?
It is pretty useful to be able to use alists as an alternative to a small hash table.
(declaim (inline racons)) (defun racons (key value ralist) (acons value key ralist))
(macrolet ((define-alist-get (name get-pair get-value-from-pair add) `(progn (declaim (inline ,name)) (defun ,name (alist key &key (test 'eql)) (let ((pair (,get-pair key alist :test test))) (values (,get-value-from-pair pair) pair))) (define-setf-expander ,name (place key &key (test ''eql) &environment env) (multiple-value-bind (dummies vals newvals setter getter) (get-setf-expansion place env) (when (cdr newvals) (error "~A cannot store multiple values in one place" ',name)) (with-unique-names (store key-val test-val alist found) (values (append dummies (list key-val test-val)) (append vals (list key test)) (list store) `(let ((,alist ,getter)) (let ((,found (,',get-pair ,key-val ,alist :test ,test-val))) (cond (,found (setf (,',get-value-from-pair ,found) ,store)) (t (let ,newvals (setf ,(first newvals) (,',add ,key ,store ,alist)) ,setter))) ,store)) `(,',name ,getter ,key)))))))) (define-alist-get alist-get assoc cdr acons) (define-alist-get ralist-get rassoc car racons))
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