SGML to XML Conversions - DTD

• XML DTD does not permit inclusions and exclusions

  • SGML:<!ELEMENT Article - - (front, body) +(%i.float;)>
  • XML:<!ELEMENT Article (front | body | %i.float;)*>

• XML DTD does not permit the ‘&’ connector

• XML DTD does not permit the use of mixed content models

  • <!ELEMENT Other ((author, journal) | (#PCDATA))>

• Result is difficult to make XML DTDs as precise and restrictive.

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