[smizell]

I wrote a little library for building DSLs in JavaScript [0] because of this very issue—JSON is not good for this kind of stuff. I want to be able to create small DSLs to solve problems rather than squeezing the language into a JSON format. I want the full power of a language AND the ability to serialize the semantics to send over the wire. Maybe we'll move toward that one day.

[0] https://github.com/smizell/treebranch

[krapp]

But you shouldn't want the full power of a Turing complete language in a config language. All of that belongs in application-space, configuration is supposed to be simple and static, with as little logic as possible, preferably none.

[smizell]

The difference is that I am not proposing a Turing complete config language, but rather proposing to build configurations with plain old JavaScript (or whatever language you want). I think a good read about this thinking is by Martin Fowler on Language Oriented Programming [0], specially the section about internal DSLs.

Another interesting read is around the configuration complexity clock [1], in that over time we move from hard coding things to building configurations to coming full circle and hard coding things again. I like to think internal DSLs closes that loop well.

[0] https://www.martinfowler.com/articles/languageWorkbench.html

[1] http://mikehadlow.blogspot.com/2012/05/configuration-complex...

[sbjs]

That’s exactly what Lua was created for, to be a Turing complete configuration language. You can remove the whole standard library though, leaving only the built in operators, variables, functions, and control flow. To some it may seem ugly to define a configuration this way but it allows configurations to reduce duplication and add more dynamism. It’s a trade for, power for simplicity. But I guess the logical end of that is to end up evolving the configuration into a scripting language which is how Lua got where it is today.

[krapp]

>You can remove the whole standard library though, leaving only the built in operators, variables, functions, and control flow.

I just choose not to use them, and limit myself to tables or an API that generates tables when using it for config files.