+ (run-hooks 'notmuch-after-tag-hook))
+ ;; in all cases we return tag-changes as a list
+ tag-changes)
+
+(defun notmuch-tag-change-list (tags &optional reverse)
+ "Convert TAGS into a list of tag changes.
+
+Add a \"+\" prefix to any tag in TAGS list that doesn't already
+begin with a \"+\" or a \"-\". If REVERSE is non-nil, replace all
+\"+\" prefixes with \"-\" and vice versa in the result."
+ (mapcar (lambda (str)
+ (let ((s (if (string-match "^[+-]" str) str (concat "+" str))))
+ (if reverse
+ (concat (if (= (string-to-char s) ?-) "+" "-")
+ (substring s 1))
+ s)))
+ tags))
+