pcitool/xml/references.xsd

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
 <xsd:include schemaLocation="types.xsd"/>

 <xsd:element name="model">
    <xsd:complexType>
      <xsd:choice minOccurs="1" maxOccurs="unbounded">
        <xsd:element name="bank" type="pcilib_bank_t" minOccurs="0" maxOccurs="unbounded" />
        <xsd:element name="transform" type="pcilib_transform_view_t" minOccurs="0" maxOccurs="unbounded" />
        <xsd:element name="enum" type="pcilib_enum_view_t" minOccurs="0" maxOccurs="unbounded">
            <xsd:key name="pcilib_value_name_key">
                <xsd:selector xpath="name" />
                <xsd:field xpath="@value" />
            </xsd:key>
        </xsd:element>
        <xsd:element name="unit" type="pcilib_unit_t" minOccurs="0" maxOccurs="unbounded">
            <xsd:key name="pcilib_unit_transform_key">
                <xsd:selector xpath="transform" />
                <xsd:field xpath="@unit" />
            </xsd:key>
        </xsd:element>
      </xsd:choice>
    </xsd:complexType>

    <xsd:key name="pcilib_bank_key">
      <xsd:selector xpath="bank" />
      <xsd:field xpath="@name" />
    </xsd:key>
<!-- Currently, we define all registers, banks, views, and units as xsd:ID which prevents them from sharing name anyway.
Currently it seems fine, but later it could turn out too be to strict. Then, we get problem also here as transform[@name]
is ID of view, not register. But how can we restrict transform field to @register only? -->
    <xsd:key name="pcilib_register_key">
      <xsd:selector xpath="bank/register|bank/register/field|transform" />
      <xsd:field xpath="@name|@register" />
    </xsd:key>
    <xsd:key name="pcilib_view_key">
      <xsd:selector xpath="transform|enum" />
      <xsd:field xpath="@name|@path" />
    </xsd:key>
    <xsd:key name="pcilib_unit_key">
      <xsd:selector xpath="unit" />
      <xsd:field xpath="@name" />
    </xsd:key>

    <xsd:keyref name="pcilib_register_view_ref" refer="pcilib_view_key">
      <xsd:selector xpath="bank/register/view|bank/register/field/view" />
      <xsd:field xpath="@view" />
    </xsd:keyref>
<!-- Actually, it is no problem to reference non-existing unit just for informative purposes
    <xsd:keyref name="pcilib_unit_ref" refer="pcilib_unit_key">
      <xsd:selector xpath="transform|enum" />
      <xsd:field xpath="@unit" />
    </xsd:keyref>
-->
 </xsd:element>
</xsd:schema>