Added nsIRDFContainer and nsIRDFContainerUtils.

    // be initialized via <tt>nsIRDFDataSource::Init()</tt>.

    nsIRDFDataSource GetDataSource(in string aURI);

};

// A wrapper for manipulating RDF containers

[scriptable, uuid(D4214E90-FB94-11D2-BDD8-00104BDE6048)]

interface nsIRDFContainer : nsISupports {

    // Initialize the container wrapper to the specified resource

    // using the specified datasource for context.

    void Init(in nsIRDFDataSource aDataSource, in nsIRDFResource aContainer);

    // Return the number of elements in the container. Note that this

    // may not always be accurate due to aggregation.

    long GetCount();

    // Return an enumerator that can be used to enumerate the contents

    // of the container in ascending order.

    nsISimpleEnumerator GetElements();

    // Append an element to the container, assigning it the next

    // available ordinal.

    void AppendElement(in nsIRDFNode aElement);

    // Remove the first occurence of the specified element from the

    // container.

    void RemoveElement(in nsIRDFNode aElement, in boolean aRenumber);

    void InsertElementAt(in nsIRDFNode aElement, in long aIndex, in boolean aRenumber);

    long IndexOf(in nsIRDFNode aElement);

};

// Container utilities

[scriptable, uuid(D4214E91-FB94-11D2-BDD8-00104BDE6048)]

interface nsIRDFContainerUtils : nsISupports {

    // Returns 'true' if the property is an RDF ordinal property.

    boolean IsOrdinalProperty(in nsIRDFResource aProperty);

    // Convert the specified index to an ordinal property.

    nsIRDFResource IndexToOrdinalResource(in long aIndex);

    // Convert the specified ordinal property into an index

    long OrdinalResourceToIndex(in nsIRDFResource aOrdinal);

    // Return 'true' if the specified resource is a container

    boolean IsContainer(in nsIRDFDataSource aDataSource, in nsIRDFResource aResource);

    // Return 'true' if the specified resource is a bag

    boolean IsBag(in nsIRDFDataSource aDataSource, in nsIRDFResource aResource);

    // Return 'true' if the specified resource is a sequence

    boolean IsSeq(in nsIRDFDataSource aDataSource, in nsIRDFResource aResource);

    // Return 'true' if the specified resource is an alternation

    boolean IsAlt(in nsIRDFDataSource aDataSource, in nsIRDFResource aResource);

    // Decorates the specified resource appropriately to make it

    // usable as an empty bag in the specified data source.

    nsIRDFContainer MakeBag(in nsIRDFDataSource aDataSource, in nsIRDFResource aResource);

    // Decorates the specified resource appropriately to make it

    // usable as an empty sequence in the specified data source.

    nsIRDFContainer MakeSeq(in nsIRDFDataSource aDataSource, in nsIRDFResource aResource);

    // Decorates the specified resource appropriately to make it

    // usable as an empty alternation in the specified data source.

    nsIRDFContainer MakeAlt(in nsIRDFDataSource aDataSource, in nsIRDFResource aResource);

};