I've written a lot of Tcl in my career. I don't know if it "fell out of favor" as much as "never really had a ton of favor even at its peak". I have used it in

I've written a lot of Tcl in my career. I don't know if it "fell out of favor" as much as "never really had a ton of favor even at its peak". I have used it in the last decade to do some build system tooling where string/regex processing of log files emitted in prior steps was a big part of the functionality. It was nice that "nobody else is using Tcl, so I won't have any versioning conflicts" and that held true for over a decade, so the long-term cost was reasonable. If I had to learn a new language today, I can't say that I'd put Tcl very high on the list, despite being overall happy with it.