@_clearGraphOnNewConnection.bind(@),

                                 @_applyPatch.bind(@),

                                 @setStatus)

  clearGraph: ->

    # just deletes the statements; watchers are unaffected.

    if @graph?

      @_applyPatch({addQuads: [], delQuads: @graph.getQuads()})

    # if we had a Store already, this lets N3.Store free all its indices/etc

    @graph = N3.Store()

    @_addPrefixes(@prefixes)

  _clearGraphOnNewConnection: -> # must not send a patch to the server!

    log('graph: clearGraphOnNewConnection')

    @clearGraph()

    log('graph: clearGraphOnNewConnection done')

  _addPrefixes: (prefixes) ->

    for k in (prefixes or {})

      @prefixes[k] = prefixes[k]

    @prefixFuncs = N3.Util.prefixes(@prefixes)

  Uri: (curie) ->

    for qs in [patch.addQuads, patch.delQuads]

      for q in qs

        if not q.equals

          throw new Error("doesn't look like a proper Quad")

        if not q.subject.id or not q.graph.id? or not q.predicate.id?

          throw new Error("corrupt patch: #{JSON.stringify(q)}")

  _applyPatch: (patch) ->

    # In most cases you want applyAndSendPatch.

    #

    # This is the only method that writes to @graph!

    @cachedFloatValues.clear()

    for quad in patch.delQuads

      #log("remove #{JSON.stringify(quad)}")

      did = @graph.removeQuad(quad)

      #log("removed: #{did}")

    for quad in patch.addQuads

      @graph.addQuad(quad)

    #log('applied patch locally', patchSizeSummary(patch))

    @_autoDeps.graphChanged(patch)

  getObjectPatch: (s, p, newObject, g) ->

    # make a patch which removes existing values for (s,p,*,c) and

    # adds (s,p,newObject,c). Values in other graphs are not affected.

    hit = @cachedFloatValues.get(key)

    return hit if hit != undefined

    #log('float miss', s, p)

    ret = parseFloat(@_singleValue(s, p).value)

    @cachedFloatValues.set(key, ret)

    return ret

  stringValue: (s, p) ->

    @_singleValue(s, p).value

  uriValue: (s, p) ->

  labelOrTail: (uri) ->

    try

      ret = @stringValue(uri, @Uri('rdfs:label'))

    catch

      words = uri.value.split('/')

      ret = words[words.length-1]

    if not ret

      ret = uri.value

    return ret

  objects: (s, p) ->