Congratulations! ECL is very mature, and this release seems to further solidify that aspect of the project. We've been using it heavily at our startup with no problems, embedded with c++. I think it's a very well done implementation. If you're thinking of trying ECL out but emacs/slime is too much to have to learn, rlwrap, is a readline wrapper that makes the REPL very friendly. To integrate with c++, the ECL manual [1] is a decent reference.

[1] https://common-lisp.net/project/ecl/manual/

Please share with us what are you using it for if you can. I'd love to hear it.

It's a very straightforward use case, actually. We have c++ code on the AI/ML side of our company, well integrated with the rest of the stack. For some of our ideas in this area though, lisp was clearly very suitable, so we tried ECL. We mostly call c++ functions from lisp, and eval some lisp code on the c++ side. It always worked without problems. I only had experience with sbcl and clisp before, but ECL proved very mature and well designed. We love it and don't intend on looking back.

Thanks! Don't forget to report a bugs if you find any :-)

Has anyone used the embedding aspect of ECL significantly? I've used ECL as a standalone Lisp system, and also done fairly trivial embedding where there isn't much more interaction than there would be if you communicated with an external Lisp system via a pipe. But curious how usable the API on the C side is for interacting with an embedded ECL, to call functions and pass data across the boundary in either direction (cl_object, cl_def_c_function, etc.). The documentation for that part seems pretty sparse.

We're working on it (documentation that is). You may find interesting directory examples/ in the source distribution archive.

An issue of ECL Quarterly was also published recently including some release coverage: https://common-lisp.net/project/ecl/quarterly/volume2.html.