I have recently been working on re-writing Zipper in C/Asm.
This is so I can more easily add zx7 compression support, which I have been working on as well.
The biggest difficulty of making such a compressor has been interpreting the zx7 code, written by Einar Saukas, which is used in the CE C toolchain. Interestingly enough, this code allocates far more memory than the calculator has... so I had to improvise and write a slightly different algorithm to find optimal pattern matches.
I'm not sure how long this project will take to complete, but I am hopeful it will take me less than a year lol.

I have successfully made a zx7 compressor, including self-extracting compressed program maker!
Currently, the code is written in C. However, I plan to rewrite critical parts in Asm, so that it may compress faster.
I will be releasing this compressor seperately from Zipper, but I do plan to integrate it in the future.