Merge branch 'master' of http://git.gnus.org/gnus into SYgnus

[gnus] / lisp / gnus-util.el

diff --git a/lisp/gnus-util.el b/lisp/gnus-util.el
index 6759c07..31645fc 100644 (file)
--- a/lisp/gnus-util.el
+++ b/lisp/gnus-util.el
@@ -1,6 +1,6 @@
 ;;; gnus-util.el --- utility functions for Gnus
 
-;; Copyright (C) 1996-2015 Free Software Foundation, Inc.
+;; Copyright (C) 1996-2016 Free Software Foundation, Inc.
 
 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
 ;; Keywords: news
@@ -1996,6 +1996,31 @@ to case differences."
   (defun gnus-timer--function (timer)
     (elt timer 5)))
 
+(defun gnus-test-list (list predicate)
+  "To each element of LIST apply PREDICATE.
+Return nil if LIST is no list or is empty or some test returns nil;
+otherwise, return t."
+  (when (and list (listp list))
+    (let ((result (mapcar predicate list)))
+      (not (memq nil result)))))
+
+(defun gnus-subsetp (list1 list2)
+  "Return t if LIST1 is a subset of LIST2.
+Similar to `subsetp' but use member for element test so that this works for
+lists of strings."
+  (when (and (listp list1) (listp list2))
+    (if list1
+       (and (member (car list1) list2)
+            (gnus-subsetp (cdr list1) list2))
+      t)))
+
+(defun gnus-setdiff (list1 list2)
+  "Return member-based set difference of LIST1 and LIST2."
+  (when (and list1 (listp list1) (listp list2))
+    (if (member (car list1) list2)
+       (gnus-setdiff (cdr list1) list2)
+      (cons (car list1) (gnus-setdiff (cdr list1) list2)))))
+
 (provide 'gnus-util)
 
 ;;; gnus-util.el ends here