If it's at compilation time, you have the full zig language so you certainly could implement your very own functional programming language https://github.com/ig

If it's at compilation time, you have the full zig language so you certainly could implement your very own functional programming language https://github.com/igmanthony/zig_comptime_lisp https://github.com/igmanthony/zig_comptime_lisp in regular zig rather in an external preprocessor.