I recently posted that I wanted to implement some modern ideas in some language that could be easily compiled or trans-coded for use my modern tools. That might mean rewriting the compiler and interpreter for the new framework but that’s OK as the savings on the other side of the equation are incalculable.
For instance rewriting a compiler is a known thing. The tools for testing the compiler based on the target scripts and language spec is very knowable, where as, rewriting the target scripts and whatever nuance might be embedded in the code that is impossible to know and it’s not possible to know whether the script or the MUT (machine under test) is at fault.
tcl is a good language to consider
TH1 is an example as to why tcl was a great choice.
The SQLite development team does all of their testing in tcl. There are vast number of tests and if thy had to rewrite the tests then all would be lost and the reliability of the tests could hold the team back years. I’m not familiar with the effort to get their tests from tcl to th1 but it’s still a great idea with a huge upside.