2 files changed, 35 insertions, 0 deletions
diff --git a/schema/interface_definition.rnc b/schema/interface_definition.rnc
index 02175fec8..0ce8226cd 100644
--- a/schema/interface_definition.rnc
+++ b/schema/interface_definition.rnc
@@ -24,9 +24,16 @@
 # Interface definition starts with interfaceDefinition tag that may contain node tags
 start = element interfaceDefinition
 {
+    syntaxVersion*,
     node*
 }
 
+# interfaceDefinition may contain syntax version attribute lists.
+syntaxVersion = element syntaxVersion
+{
+    (componentAttr & versionAttr)
+}
+
 # node tag may contain node, leafNode, or tagNode tags
 # Those are intermediate configuration nodes that may only contain
 # other nodes and must not have values
@@ -97,6 +104,16 @@ properties = element properties
     (element keepChildOrder { empty })?
 }
 
+componentAttr = attribute component
+{
+    text
+}
+
+versionAttr = attribute version
+{
+    text
+}
+
 # All nodes must have "name" attribute
 nodeNameAttr = attribute name
 {
diff --git a/schema/interface_definition.rng b/schema/interface_definition.rng
index 195ef27f4..bfd8d376f 100644
--- a/schema/interface_definition.rng
+++ b/schema/interface_definition.rng
@@ -29,10 +29,22 @@
   <start>
     <element name="interfaceDefinition">
       <zeroOrMore>
+        <ref name="syntaxVersion"/>
+      </zeroOrMore>
+      <zeroOrMore>
         <ref name="node"/>
       </zeroOrMore>
     </element>
   </start>
+  <!-- interfaceDefinition may contain syntax version attribute lists. -->
+  <define name="syntaxVersion">
+    <element name="syntaxVersion">
+      <interleave>
+        <ref name="componentAttr"/>
+        <ref name="versionAttr"/>
+      </interleave>
+    </element>
+  </define>
   <!--
     node tag may contain node, leafNode, or tagNode tags
     Those are intermediate configuration nodes that may only contain
@@ -184,6 +196,12 @@
       </interleave>
     </element>
   </define>
+  <define name="componentAttr">
+    <attribute name="component"/>
+  </define>
+  <define name="versionAttr">
+    <attribute name="version"/>
+  </define>
   <!-- All nodes must have "name" attribute -->
   <define name="nodeNameAttr">
     <attribute name="name"/>