A system and method for dynamically composing a class is provided. A query is parsed and a compiler object tree is generated that corresponds to the operators in the query. A set of feature requests and responses are initiated and a set of feature objects are generated that are executed at runtime. The language of the query may be extended by registering a new operator, and optionally a new feature for a query language, with a search engine without modifying the source code of the search engine. The new operator may be specified in a plug-in and provided to the search engine via the plug-in. An application converts an end user query into an application query that conforms to the query language supported by the search engine and includes the new operator. The application query may also include references to traditional programming constructs and search engine primitives.