def next_selection(obj):
if isinstance(obj, mutable.Document):
return mutable.Selection(obj, len(obj))
index = obj.parent.index(obj)
if mutable.isstruct(obj.parent):
if index + 1 < len(obj.parent):
nxt = obj.parent[index+1]
if mutable.islist(nxt):
return mutable.Selection(nxt, 0)
else:
return nxt
else:
return next_selection(obj.parent)
else:
return mutable.Selection(obj.parent, index+1)
def prev_selection(obj):
if isinstance(obj, mutable.Document):
return mutable.Selection(obj, 0)
index = obj.parent.index(obj)
if mutable.isstruct(obj.parent):
if index > 0:
nxt = obj.parent[index-1]
if mutable.islist(nxt):
return mutable.Selection(nxt, len(nxt))
else:
return nxt
else:
return prev_selection(obj.parent)
else:
return mutable.Selection(obj.parent, index)