I hope you're wrong about Lua, which I've never used. But allow me to say that I have to use Tcl, and I hate it. I want to like it, the syntax is clean and code has a nice look to it.

But the everything-is-a-string [1] semantics is awkward to deal with. As with shell scripting, a lot of what you do amounts to solving problems with quoting. I find Tcl hard to debug, and I don't like the scoping (upvar!).

I'd much rather use Emacs Lisp. In fact, Cadence uses a language of their own, called Skill, for some of their tools. It's so close to Emacs Lisp it may as well be identical, and it's far easier to deal with than Tcl.

[1] That's no longer true under the hood. But Tcl behaves as if it's true.