There's lots of new stuff, and some old cruft has been dumped, so some programs may need a few updates, but there's still a high level of compatibility. The page above links to release notes with details of what's in and what's out.

This is huge! A big portion of why concurrency in Tcl was so dated and why the language was considered so non-performant was because it relied on `select` despite `epoll` and `kqueue` being available for at least a decade.

Tcl is one of my favorite languages because of how easy it is to get started with and how easy metaprogramming is.

OpenACS [2] is the main project of, which has existed since 1997 and that alone is highly powerful in what it can do with. Especially when coupled with TCL. It's still maintained and now supports TCL9 too!

Javascript, TCL and NaviServer (and which has it's own modules such as DNS Server, LDAP, Mail really makes an powerful tool.

If you're looking to get in to TCL and Web Development, you can really create fun with the two combined. I highly recommend that if you wish to dabble with something on the side for easy learning and plentiful features. Go take a look.

[0] https://wiki.tcl-lang.org/page/NaviServer

https://github.com/naviserver-project/naviserver

[1] https://news.ycombinator.com/item?id=35648805

https://www.linuxjournal.com/article/6164

[2] https://openacs.org/about/history

https://openacs.org/

"Interesting footnote: the founding of Netscape occurred at the same time I was deciding where to go in industry when I left Berkeley in 1994. Jim Clarke and Marc Andreessen approached me about the possibility of my joining Netscape as a founder, but I eventually decided against it (they hadn't yet decided to do Web stuff when I talked with them). This is one of the biggest "what if" moments of my career. If I had gone to Netscape, I think there's a good chance that Tcl would have become the browser language instead of JavaScript and the world would be a different place! However, in retrospect I'm not sure that Tcl would actually be a better language for the Web than JavaScript, so maybe the right thing happened."

Source: https://pldb.io/blog/JohnOusterhout.html

A Philosophy of Software Design:

https://web.stanford.edu/~ouster/cgi-bin/book.php

Anybody using it for something else and can speak to why you’d use it today? Genuinely curious; I don’t hate the language but can never bring myself to enjoy it either.

It’s too bad there’s not a simple way to get up and running with packages because for me so far that had been the biggest barrier to entry / deterrent. Also, I wanted to create a ES256 JWT but there’s no good way to do that apparently, due to the dated ecosystem, whereas in other languages this sort of this is just a package install away. I found a third-party solution in the form of Chilkat software but it costs $300 to license.

So overall while I think TCL is fun, I can see why people don’t choose it when they want to be productive fast and not have to fuss around with deeply manual things that are commonplace and quick in other languages.

Nice to see a new release coming out not too long after such a question :)

How does Tcl fare under these criteria?