SICL-bytecode

This repository will eventually contain a bytecode-only version of the SICL Common Lisp implementation. We are using the bytecodes from the Maclina Common Lisp library, initially designed for the Clasp Common Lisp implementation.

We are making a bytecode-only version for several reasons:

• It is easier to debug a system based on bytecodes than a system based on native machine code.

• Many issues in the SICL system can be found and fixed before we make a system with native code generation.

• We can design a real debugger in a system using bytecodes without slowing down the code too much, since it is already not that fast. Experience with a real debugger can then be used in a system with native code generation.

• Perhaps the most crucial part of SICL is the bootstrapping procedure. This procedure makes it possible to use external libraries that implement part of the Common Lisp standard, yet use the full language for the implementation. A bytecode-only version of SICL will confirm the validity of the bootstrapping procedure.

• We hope to generate interest for SICL relatively early with a bytecode-only version. A version that generates native code will take much longer to create.

• Some libraries that are required for a version of SICL that generates native code are not yet usable, and we have no estimated time for them to be usable.

To simplify the transition from a bytecode version of SICL to a version that generates native code, the bytecode version uses the object representation designed for the version with native code generation.