xsd-nested

<?xml version="1.0"?>
<x:schema xmlns:x="http://www.w3.org/2001/XMLSchema" xmlns:s="http://www.w3.org/2001/XMLSchema">
    <x:complexType name="Component">
        <x:attribute name="id" type="x:token"/>
        <x:attribute name="x" type="x:float"/>
        <x:attribute name="y" type="x:float"/>
        <x:attribute name="sprite" type="x:string"/>
    </x:complexType>
    <x:element name="Component" type="Component"/>
    
    <x:complexType name="Button">
        <x:complexContent>
            <x:extension base="Component"/>
        </x:complexContent>
    </x:complexType>
    <x:element name="Button" type="Button" substitutionGroup="Component"/>

    <x:complexType name="Container">
        <x:complexContent>
            <x:extension base="Component">
                <x:sequence>
                    <x:element ref="Component" maxOccurs="unbounded"/>
                </x:sequence>
            </x:extension>
        </x:complexContent>
    </x:complexType>
    <x:element name="Container" type="Container" substitutionGroup="Component"/>

    <x:complexType name="VGroup">
        <x:complexContent>
            <x:extension base="Container" />
        </x:complexContent>
    </x:complexType>
    <x:element name="VGroup" type="VGroup" substitutionGroup="Container"/>

    <x:complexType name="HGroup">
        <x:complexContent>
            <x:extension base="Container"/>
        </x:complexContent>
    </x:complexType>
    <x:element name="HGroup" type="HGroup" substitutionGroup="Container"/>

    <x:complexType name="View">
        <x:sequence>
            <x:element ref="Component" maxOccurs="unbounded"/>
        </x:sequence>
    </x:complexType>

    <x:element name="View" type="View"/>
</x:schema>