[PhaseLockk]

I'm not that guy, but here's my interpretation: tcl is used as the embedded scripting language in the vast majority of EDA tools. In some ways it performs this job quite well, with tool companies providing functions which parse their arguments like inputs to a shell script. For example, you can call

  report_timing -from ... -to ...

When the commands have 50 optional parameters, this method of calling is convenient.

However, the problem is that it has been pushed to its absolute limit. Massive automated design flows consisting of tens to hundreds of thousands of lines of often highly unstructured tcl are present at most semiconductor companies. All of this code is written by VLSI engineers who have not much software training. These engineers take advantage of the highly dynamic nature of tcl to solve their problems quickly... and the result is often an unmaintainable mess of code. As an example, I've almost never seen anyone use tcls module system, instead its just scripts using the `source` function to load other scripts.

Since the language is not mainstream among software engineers, there is very little material on best practices, and semiconductor companies are extremely locked down meaning there is no open source tooling to speak of. So VLSI engineers continue producing spaghetti code to handle all of the implementation.

Obviously I am speaking in very broad strokes, so there may be companies out there that do it right.