There are dozens of Scheme implementations. Are they all obsolete now that Racket exists and Chez Scheme is free? I don't think so! There are lots of sweet spot

There are dozens of Scheme implementations. Are they all obsolete now that Racket exists and Chez Scheme is free? I don't think so! There are lots of sweet spots and lots of implementation to fill the niches. This is something I really like about Scheme! Scheme 9 is small, super-portable (it only requires a C89 compiler, no libraries, no language extensions), and quite easy to grok if you are into studying the internals. Edit: typos. This is what you get for replying right after your afternoon nap. :)