I am not sure if I understand correctly. So this is a scheme running on a scheme. You need e.g. Chicken to compile/minify it and then run it via Gambit.... Why? Why would I do, except of learning puroposes of course, do such thing. I clearly am missing something.
You need a Scheme interpreter (Gambit, Chicken or Guile have been tested) to run the Ribbit AOT compiler. The Ribbit AOT compiler will compile a Scheme program to one of the supported target languages: C, JavaScript, Python, Scheme or POSIX shell script. Ribbit has been designed for a small footprint, so the generated target code is quite compact (as small as 2-4 KB for small programs). This is much more compact than any other existing Scheme system. Moreover the system is very portable to other target languages because Ribbit is implemented with a tiny virtual machine. There are ports underway to Java, Scala, Lua, Rust, go, Ruby, Haskell, and Idriss. This means a larger program in any of these languages can embed the Ribbit VM for scripting or other purposes.
Ribbit is also bootstrapped (it can compile itself). This means that you only need another Scheme system for the initial step of the bootstrap to compile the Ribbit compiler to one of the supported target languages. After this step the Ribbit compiler only needs an implementation of the target language to run. For example, you can use the Gambit interpreter to compile the Ribbit compiler to a POSIX shell script (about 64K bytes). After this is done then you only need a POSIX shell to compile any Scheme program to C, JavaScript, Python, or POSIX shell script.
In its current state the POSIX shell target is mostly a proof of concept to demonstrate that the Ribbit VM is extremely portable. One area of practical use is for bootstrapping compilers for other languages using minimal tools (see the Mes project https://bootstrappable.org/projects/mes.html for bootstrapping gcc to have a reproducible build process for gcc). With Ribbit's POSIX shell target it would be possible to build gcc on any system that has a POSIX shell (without needing other build tools like a C compiler, linker, etc).
