How to create custom keyboard shortcuts for GTKTreeView?

[Jez <jezreel gmail com>]

I would like the user to be able to scroll up and down the treeview,
expand/close rows etc with the keyboard. This is already possible with
the arrow keys; however, I would like to use different ones.

I'm pretty new to Gtk programming so I might be missing out something
here, but this is my problem:

As far as I can tell, the best way to change the selected row is

void        gtk_tree_view_set_cursor        (GtkTreeView *tree_view,
                                             GtkTreePath *path,
                                             GtkTreeViewColumn *focus_column,
                                             gboolean start_editing);

However, the problem arises when I try to manipulate the GtkTreePath.
Functions like gtk_tree_path_next and gtk_tree_model_iter_next move
the path to point to the next node at the *current* depth. If the node
is the last one at depth n, it doesn't automatically jump to the next
node at depth n-1. So basically to get this to work properly I need to
go through a number of contortions to find out of the node is the last
one (or the first one) for its depth, and I have to track the expanded
/ collapsed state of each node in the tree (because gtk doesn't seem
to provide an API to check whether a row is expanded -- it just emits
signals when the expansion occurs.)

Is there a better way to do this?

Regards,

Jez