D has pure functions: https://dlang.org/spec/function.html#pure-functions https://dlang.org/spec/function.html#pure-functions D's pure functions are quite str

D has pure functions: https://dlang.org/spec/function.html#pure-functions https://dlang.org/spec/function.html#pure-functions D's pure functions are quite strict. It can be a challenge to write a function that passes strict purity guarantees - but the result is worth it!