D's syntax isn't quite as nice as, say, Haskell (which strongly depends on preference anyway), but it has all the necessary tools to write strongly pure, refere

D's syntax isn't quite as nice as, say, Haskell (which strongly depends on preference anyway), but it has all the necessary tools to write strongly pure, referentially-transparent functions. There's the `pure` and `immutable` keywords that let the compiler statically verify the above properties.