+** DONE Allow users to access selected and current node details.
+
+** IN-PROGRESS Implement bookmark system
+
+ Currently the bookmark page replaces the current page, and it
+ does so silently (i.e. it doesn't become part of the link hierarchy).
+ I think this is a mistake, as it results in confusing behaviour when
+ traversing the link hierarchy after visiting one of the bookmarked links.
+
+ Instead, I think I should
+ 1. Make the bookmark page part of the hierarchy, and
+ 2. Reinstate the visited node hash table to avoid excess link hierarchy pollution.
+
+ In order to accomplish 1. it will be necessary to make the bookmark page renderer
+ a proper getter function, and one that never caches the contents of the buffer.
+
+ Actually, I might have to think about that a bit more. I don't know
+ how to answer the question of what the best thing to do with node
+ parent links when using a cached node in place of a new node. (Maybe
+ I always update node.parent unless parent is already an ancestor of
+ node?)
+
+** TODO Allow multiple elpher buffers
+
+ Shouldn't be too hard, just need elpher-current-node to be
+buffer-local and allow various buffer-switching procedures to
+do something sensible.
+
+** TODO Turn on lexical scoping