My 2¢: 90% of the time config files are simple enough for something like json (+ comments) The other 10% of the time where you need some level of logic to modi

My 2¢: 90% of the time config files are simple enough for something like json (+ comments) The other 10% of the time where you need some level of logic to modify some setting value, there's no substitute for something that people are already familiar with. Just let people have their 3 line js function instead of a 2-3 other dependencies that add more convoluted logic to the build system. Trying to create a config specific language with more advanced features/logic is an absolute mess where you end up learning a second language, people are unhappy with how certain features aren't implemented, and others are unhappy with how too many features exist, and it's just all round chaos. tl;dr There should be no inbetween: Either you have a simple key/value config file that someone can learn in 5 minutes, or you let people use a language they're already familiar with.