| AttributeReference | Represents a attribute reference node (like .b) in the expression tree |
| ClassAd | The ClassAd object represents a parsed ClassAd |
| ClassAdIterator | An object for iterating over the attributes of a ClassAd--deprecated |
| ClassAdParser | This reads ClassAd strings from various sources and converts them into a ClassAd |
| ClassAdUnParser | This converts a ClassAd into a string representing the ClassAd |
| ClassAdXMLUnParser | This converts a ClassAd into an XML string representing the ClassAd |
| ExprList | Represents a list of expressions, like {1, 2, 3} |
| ExprListIterator | An iterator for an ExprList--deprecated: you should use the STL-like iterators now |
| ExprTree | A node of the expression tree, which may be a literal, attribute reference, function call, classad, expression list, or an operator applied to other ExprTree operands |
| FunctionCall | Node of the expression which represents a call to an function |
| Literal | Represents the literals of the ClassAd language, such as integers, reals, booleans, strings, undefined and real |
| MatchClassAd | Special case of a ClassAd which make it easy to do matching |
| Operation | Represents a node of the expression tree which is an operation applied to expression operands, like 3 + 2 |
| PrettyPrint | This is a special case of the ClassAdParser which prints the ClassAds more nicely |
| Value | Represents the result of an evaluation |