The best of both worlds is to use a de facto standardized non-executable format like INI or JSON that nearly every language supports. Then if you need to, you

The best of both worlds is to use a de facto standardized non-executable format like INI or JSON that nearly every language supports. Then if you need to, you can create complex or overly long configuration files in Python by inserting keys into a dictionary and dumping to ConfigParser (or however your favourite language does things). For example, its useful when writing a test for many permutations of something similar. Meanwhile the parsing side is simple enough to be re-implemented in an hour when the time comes to rewrite your whole stack in C+Verilog for real ultimate performance. The 2 main things are: 1) Using your own bespoke config format or some pet format that's not widely supported adds needless friction to writing little duct tape scripts, testing harnesses, and misc tools. It also adds unnecessary difficulty when porting parts of your program to new languages. 2) Using a Turing complete config format even if it's not bespoke makes all the drawbacks in (1) even more apparent.