subname = graph.label(subUri)

    if expr is None:

        expr = '%s(t)' % subname

    print "req to add %r" % subUri

    for s in graph.triples((subUri, None, None)):

        print s

    term = Subterm(Submaster.Submaster(graph=graph, sub=subUri),

                   Subexpr(curveset,expr))

    subterms.append(term)

    stv=Subtermview(ssv, graph, term)

    # stv.pack(side='top',fill='x')

    ssv.add_subtermview(stv)

    return term

def sub_commands_tk(master, curveset, subterms, root, ssv, graph):

    f=tk.Frame(master,relief='raised',bd=1)

    newname = tk.StringVar()

    def add_cmd():

        add_one_subterm(graph, L9['sub/%s' % newname.get()],

        newname.set('')

    def reload_subs():

        dispatcher.send('reload all subs')

    tk.Button(f, text="reload subs (C-r)", 

        command=reload_subs).pack(side='left')

    tk.Label(f, text="new subterm named:").pack(side='left')

    entry = tk.Entry(f, textvariable=newname)

    entry.pack(side='left', fill='x', exp=1)

    entry.bind("<Key-Return>", lambda evt: add_cmd())

    return f

def savesubterms(filename,subterms):

    raise NotImplementedError

    s=""

    for st in subterms:

        s=s+"%s %s\n" % (st.submaster.name, st.subexpr.expr)

    file(filename,'w').write(s)

def createSubtermGraph(song, subterms):

    """rdf graph describing the subterms, readable by add_subterms_for_song"""