self.write(open("light9/effecteval/effect.html").read())

    def delete(self):

        graph = self.settings.graph

        uri = URIRef(self.get_argument('uri'))

        with graph.currentState(tripleFilter=(None, L9['effect'], uri)) as g:

            song = ctx = list(g.subjects(L9['effect'], uri))[0]

        self.settings.graph.patch(Patch(delQuads=[

            (song, L9['effect'], uri, ctx),

            ]))

class SongEffects(PrettyErrorHandler, cyclone.web.RequestHandler):

    def post(self):

        song = URIRef(self.get_argument('uri'))

        dropped = URIRef(self.get_argument('drop'))

        ctx = song

        graph = self.settings.graph

        effect = graph.sequentialUri(song + "/effect-")

        quads = [

            (song, L9['effect'], effect, ctx),

            (effect, RDF.type, L9['Effect'], ctx),

        ]

        with graph.currentState(

                tripleFilter=(dropped, None, None)) as g:

            droppedLabel = g.label(dropped)

        if L9['EffectClass'] in droppedTypes:

            quads.extend([

                (effect, RDFS.label, droppedLabel, ctx),

                (effect, RDF.type, dropped, ctx),

                ] + [(effect, L9['code'], c, ctx) for c in droppedCodes])

            curve = graph.sequentialUri(song + "/curve-")

            cr = CurveResource(graph, curve)

            cr.newCurve(ctx, label=Literal('sub %s' % droppedLabel))

            cr.saveCurve()

            quads.extend([

                (song, L9['curve'], curve, ctx),                

                (effect, L9['code'],

                 Literal('out = %s * %s' % (dropped.n3(), curve.n3())),

                 ctx),

                ])

        else:

            raise NotImplementedError(

                "don't know how to add an effect from %r (types=%r)" %

                (dropped, droppedTypes))

        graph.patch(Patch(addQuads=quads))

class SongEffectsUpdates(cyclone.websocket.WebSocketHandler):

    def connectionMade(self, *args, **kwargs):

        self.graph = self.settings.graph

        self.graph.addHandler(self.updateClient)

    def updateClient(self):

        # todo: abort if client is gone