The XRL system reported in this paper is an integrated knowledge programming environment whose major research theme is the investigation of declarative knowledge programming styles and features and of the way they can be effectively integrated and used to support AI programming. This investigation is carried out in the context of the structured-object representation paradigm which provides the glue keeping XRL components together. The paper describes several declarative programming styles and associated support tools available in XRL. These include an instantiation system supporting a generalized view of the ubiquous frame installation process, a description based programming system providing a novel declarative programming style which embeds a mathematical oriented description language in the structured object environment and a transformational interpreter for using it, a semantics oriented programming framework which offers a specific semantic construct based approach supporting maintenance and evolution and a self description and self generation tool which applies the latter approach to XRL itself. 29 refs., 16 figs.