Welcome to the new platform of Programmers Heaven! We apologize for the inconvenience caused, if you visited us from a broken link of the previous version. The main reason to move to a new platform is to provide more effective and collaborative experience to you all. Please feel free to experience the new platform and use it's exciting features. Contact us for any issue that you need to get clarified. We are more than happy to help you.
DTD special characters in enumeration
I would like to insert in a DTD the following ATTLIST:
<!ATTLIST elem operator (=|<>) #REQUIRED>
but the validator tells me that the DTD is not valid, with this error:
Invalid item '=' in DTD ATTLIST Enumeration
Does someone know what I should write to have a correct DTD with the special characters I want to insert?