Syntax

This chapter address various (pretty minor) syntax issues. If you want the whole story, see the full Relax NG schema, or nvdl.html which is a prettier version of the same information.

I stated earlier that I will only use Relax NG syntax for the schemas and sub-schemas. Taking an example of others is not a problem. Example 6.1

Example 6.1. Alternate schema usage

<?xml version="1.0" encoding="utf-8"?>
<!-- syntax.ex1.nvdl -->
<rules xmlns="http://purl.oclc.org/dsdl/nvdl/ns/structure/1.0" 
       startMode="doc">

  <mode name="doc">
    <namespace ns="http://document">                                 
      <validate                                    
      message="A variant on the schema specification"           
      schemaType="application/x-rnc">                 
	<schema>routing.1.rnc</schema>
      </validate>
    </namespace>
  </mode>

  <mode name="rest">
    <namespace ns="http://head" >
      <validate schema="routing.1.xsd" />  
    </namespace>

    <namespace ns="http://body">
      <validate  schemaType="application/xml-dtd" 
      schema="routing.1.dtd" />          
    </namespace>
  </mode>
</rules>        
   
  

	Rather than using the schema attribute this example uses the schema element. The message attribute enables helpful comments in the script.
	Validating with the abbreviated syntax, the schemaType must be specified.
	We can even use DTD's.

Due care though. The standard says, “If v contains a schema element as a child, its content is used as the schema. When the content is a string and v has the schemaType attribute, its value shall be a MIME mediatype (see IETF RFC2046) and be used for determining the schema language. When the content is a foreign element, its namespace is used for determining the schema language.” Put simply, if it's a modern XML based schema language, then you should be OK. Otherwise specify the mimetype as per RFC2046 (ietf rfc2046).