First commit.

lisp/lib/list.el

@@ -0,0 +1,46 @@
+;;; list.el --- Emacs list utilities -*- lexical-binding: t; -*-
+;;; Commentary:
+;;; Code:
+
+(defun add-many-to-list (the-list &rest entries)
+  "Add to THE-LIST any specified ENTRIES."
+  (dolist (entry entries)
+    (add-to-list the-list entry))
+  (eval the-list))
+
+
+(defmacro user/filter-form (form list)
+  "Return list with elements for which FORM are non-nil in LIST."
+  (declare (debug (form form)))
+  (let ((r (make-symbol "result")))
+    `(let (,r)
+       (--each ,list (when ,form (!cons it ,r)))
+       (nreverse ,r))))
+
+
+(defun user/filter-list (condp list)
+  "Return list with elements for which CONDP are non-nil in LIST."
+  (delq nil
+        (mapcar (lambda (x) (and (funcall condp x) x)) list)))
+
+
+(defun user/toggle-element (list element)
+  "Return LIST with ELEMENT removed if present or added if not present."
+  (if (member element list)
+      (user/filter-form (not (eq element it)) list)
+    (cons element list)))
+
+
+(defun user/all-asscs (asslist query)
+  "A list of all values in ASSLIST corresponding to QUERY (like rassoc)."
+  (cond
+   ((null asslist) nil)
+   (t
+    (if (equal (cdr (car asslist)) query)
+        (cons (car (car asslist))
+              (user/all-asscs (cdr asslist) query))
+      (user/all-asscs (cdr asslist) query)))))
+
+
+(provide 'lib/list)
+;;; list.el ends here