Hi All, I managed to get guile-log and guile-syntax-parse to work under guile-2.2. So It looks like it will be a smooth transition from here. I did have a few hiccups but managed to clean them out. No issues with guile-2.2. Master is looking good. But most of my work recently have been on making it possible to run swi-prolog code and use the prolog module system. I can compile pretty advanced code quite well almost without no hiccups. So if you stay out of swi prolog internals in your prolog code guile-swi-prolog will be able to compile and parse it. mainly swi prolog macros is partly implemented and needs some rework to use it. And getting prolog macros to work is where I am atm. I did a small test with swi prologs assoc data structure which is a functional tree. I also compared with an internal vhash that i'm using as an assoc looking upp all the 1 .. 10.000 numbers in an assoc data structure, here is the finding Number of operations / second: swi assoc.pl 100.000 guile-prolog (guile 2.0) assoc 10.000 vhash 100.000 guile-log (guile 2.0) vhash 1.000.000 So although guile-log is 10x slower when you run the same code as in prolog, using an internal data structure, you gain 10x, and skipping the overhead of guile-log's prolog implementation another 10x is gained. So actually a prolog on scheme can be really fast, if you do it right. Unfortunately pure prolog is too slow atm, but it will be better as the prolog implementation get's better and guile get's it code all the way to assembler. Swi prolog has a lot of cool features, many of them are implemented. That together with a really good implementation of tablating and continuations makes guile-log's prolog unique. Right now I'm trying to compile clpfd which is a finite domain solver, something that one just must have in order to call oneself a prolog environment. Happy hacking!