Parameter Entity References for Namespace Prefixes

• Must use double indirection

• <!ENTITY % NS.prefixed     "IGNORE" >
  <!ENTITY % MATHML.prefixed "%NS.prefixed;" >
  
  <!ENTITY % MATHML.xmlns    "http://www.w3.org/1998/Math/MathML" >
  <!ENTITY % MATHML.prefix   "m" >
  <![%MATHML.prefixed;[
    <!ENTITY % MATHML.xmlns.extra.attrib  "" >
  ]]>
  <!ENTITY % MATHML.xmlns.extra.attrib "" >
  
  <![%MATHML.prefixed;[
  <!ENTITY % MATHML.pfx  "%MATHML.prefix;:" >
  <!ENTITY % MATHML.xmlns.attrib
       "xmlns:%MATHML.prefix;  CDATA   #FIXED '%MATHML.xmlns;'
        %MATHML.xmlns.extra.attrib;"
  >
  ]]>
  <!ENTITY % MATHML.pfx  "" >
  <!ENTITY % MATHML.xmlns.attrib
       "xmlns CDATA #FIXED '%MATHML.xmlns;'
        %MATHML.xmlns.extra.attrib;"
  >
  
  <![%NS.prefixed;[
  <!ENTITY % XHTML.xmlns.extra.attrib 
       "%MATHML.xmlns.attrib;" >
  ]]>
  <!ENTITY % XHTML.xmlns.extra.attrib ""
  >
  
  <!-- Section B: MathML Qualified Names ::::::::::::::::::::::::::::: -->
  
  <!-- 9. This section declares parameter entities used to provide
          namespace-qualified names for all MathML element types.
  -->
  
  <!ENTITY % abs.qname  "%MATHML.pfx;abs" >
  <!ENTITY % and.qname  "%MATHML.pfx;and" >
  

  ...

• Only works in external DTD subset