A Blond Primer

This report describes how to use the reflective tower Blond. A reflective tower is a computational architecture where programs are given access to representations of the current state of computation. This models an infinite tower of interpreters interpreting each other, meta-circularly. Blond is a Scheme interpreter extended to be reflective. This report concentrates on its reflective extension rather than on the standard Scheme characteristics. Reification, reflection, reified environments, and reified continuations are described in detail. Each key point is illustrated with scenarios. The first entries in a Blond library are assembled, and finally Blond is run in Blond, achieving orthogonal reflective towers. A glossary and the Scheme source code are provided in appendix. This report informally describes its 1988 implementation, as specified in the article “Intensions and Extensions in a Reflective Tower”, presented at the 1988 ACM Symposium on Lisp and Functional Programming, where Blond is formally described.