@roka @awg "multiple" is sort of an understatement. It feels like the only language that has more implementations is !forth . :-)
Many people like #racket, as it has an IDE that is very helpful to newcomers. #Chez is performant and complete. I quite like #guile as it's GNU, used for #guix and has some intriguing new async stuff I'd like to play with.
A decade ago when I did #SICP in uni, the course recommended Racket (then Dr Scheme) or MIT Scheme, but I used Guile because it had a very POSIX-y and familiar command line and I wrote my lab exercises with Makefiles running the tests.
Back then I also had a look at #gauche (also very script-y and POSIX-y) and #scheme48, which integrates well with SMILE in emacs. These days there's #geiser for guile, which is likely to be the best emacs+Scheme interactive mode out there.
- nyacc is used by mes, but is now unbundled from it. - nyacc is a C99 parser, ie C99 -> AST - mescc is a C99 compiler, ie AST -> M - mes is a scheme interpreter that can run mescc - nyacc in an amazing parser generator framework that comes with an almost complete c99 parser and preprocessor
The 1.8 vendoring went in at https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=746005#278 and it seems that the issues migrating to 2.0 were not language-related any more, but that #lilypond probably uses more of the #guile API than any other software and exposed several issues with it. It also seems that this is being worked on (module time available to the participants) and should be fixed at some point, maybe already within this decade. :-)
But then https://packages.debian.org/buster/lilypond looks like it vendors guile-1.8, so I guess it wasn't enough? There's a debian bug also that I haven't read yet ("please migrate to guile-2.0").
@charlag @taknamay Also check out @cwebber , which is currently busy making a test suite for the next social network protocol -- and the test suite is written in !scheme. Not to mention being active with #guix and writing the http://gnu.org/s/8sync #guile async actor framework.
Who else would have thought of making your presentation a MUD, and then live-hacking that MUD taking suggestions from the audience? cwebber would, apparently.