<!-- Document Type Definition for ClassAds (Classified Advertisements, as used
in Condor. See http://www.cs.wisc.edu/condor for more information. -->
<!-- Root element: a sequence of ClassAd elements -->
<!ELEMENT classads (i | r | s | e | b | at | rt | un | er | l | c)*>
<!-- A ClassAd (Classified Advertisement): A set of "attributes". -->
<!ELEMENT c (a)* >
<!-- An "attribute" contains a named element -->
<!ELEMENT a (i | r | s | e | b | at | rt | un | er | l | c)>
<!ATTLIST a n CDATA #REQUIRED>
<!-- Numbers -->
<!ELEMENT i (#PCDATA)> <!-- An integer (sequence of digits) -->
<!ELEMENT r (#PCDATA)> <!-- A real number in "scientific" notation -->
<!-- Strings -->
<!ELEMENT s (#PCDATA)>
<!-- Sub-expressions in native syntax -->
<!ELEMENT e (#PCDATA)>
<!-- Booleans: no content, but one mandatory attribute v=t or v=f -->
<!ELEMENT b EMPTY>
<!ATTLIST b v (t | f) #REQUIRED >
<!-- Timestamps -->
<!ELEMENT at (#PCDATA)> <!-- Absoute time, e.g. 2003-01-25T09:00:00-06:00 -->
<!ELEMENT rt (#PCDATA)> <!-- Relative time, e.g. P1H15M13.257S -->
<!-- Undefined and error -->
<!ELEMENT un (#PCDATA)> <!-- Undefined; content, if any, is "annotation" -->
<!ELEMENT er (#PCDATA)> <!-- Error; content, if any, is "annotation" -->
<!-- A List: a sequence of ClassAd elements -->
<!ELEMENT l (i | r | s | e | b | at | rt | un | er | l | c)*>