List of paths to nested dictionary Given a list of nested menu items,

items = [
    '3D/Axis',
    '3D/CameraTracker',

    'Color/Invert',
    'Color/Log2Lin',

    'Color/Math/Add',
    'Color/Math/Multiply',

    'Other/Group',
    'Other/NoOp',

    'Views/JoinViews',
    'Views/ShuffleViews',

    'Views/Stereo/Anaglyph',
    'Views/Stereo/ReConverge',
]


..and a dummy function to be triggered by each item:

def msg(path):
    """Dummy function used in menu
    """
    return path.lower()


Programatically create a hierarchal collection of dictionaries, which is equivalent to manually typing this:

menu = {
    '3D': {'Axis':                     lambda: msg('3D/Axis'),
           'CameraTracker':            lambda: msg("3D/CameraTracker")},

    'Color': {'Invert':                lambda: msg('Color/Invert'),
              'Log2Lin':               lambda: msg('Color/Log2Lin'),

              'Math': {'Add':          lambda: msg('Color/Add'),
                       'Multiply':     lambda: msg('Color/Multiply')}},

    'Other': {'Group':                 lambda: msg('Other/Group'),
              'NoOp':                  lambda: msg('Other/NoOp')},

    'Views': {'JoinViews':             lambda: msg('Views/JoinViews'),
              'ShuffleViews':          lambda: msg('Views/ShuffleViews'),
              'Stereo': {'Anaglyph':   lambda: msg('Views/Stereo/Anaglyph'),
                         'ReConverge': lambda: msg('Views/Stereo/ReConverge')}}},


..which could be tested as follows:

assert menu['3D']['Axis']() == '3d/axis'
assert menu['Color']['Invert']() == 'color/invert'
assert menu['Color']['Math']['Add']() == 'color/math/add'
assert menu['Views']['Stereo']['Anaglyph']() == 'views/stereo/anaglyph'
A simple recursion will do the work

def build_nested_helper(path, text, container):
    segs = path.split('/')
    head = segs[0]
    tail = segs[1:]
    if not tail:
        container[head] = lambda: msg(text)
    else:
        if head not in container:
            container[head] = {}
        build_nested_helper('/'.join(tail), text, container[head])

def build_nested(paths):
    container = {}
    for path in paths:
        build_nested_helper(path, path, container)
    return container

menu = build_nested(items)


squashed code: 159 chars

def f(p,t,c):
 s=p.split('/');a=s[0];b=s[1:]
 if b:
  if a not in c:c[a]={}
  f('/'.join(b),t,c[a])
 else:c[a]=lambda:msg(t)
menu={}
for i in items:f(i,i,menu)