Closures are definitely cumbersome in Rust, and Lisp/Haskell/Scala programmers use them all the time. In SICP for example, they translate several math equations to code using higher order functions and closures, and it is wonderful how clean the code is, and how close to the actual mathematics.
That's what i meant it is impossible to do in Rust. From that point of view, Rust is a low level procedural language, but expressing any kind of business logic it is almost as high level as Haskell or Java.
But if we focus on error detection, then Rust is the highest level of any other PL. For example Java or Python are too low level when an error occurs. That high level of error detection is paid of course, and that is by longer compilation times.
If i had a wish though, i would wish Rust had as good closures as Haskell or Lisp.
In principle you could fix any lack of syntactic sugar (which is what leads to the "clean code" feel in Scheme or Haskell - but even Swift has custom sugar of its own for refcounting and copy-on-write) with a custom macro - which would be entirely optional, triggered by a custom attribute such as #[sloppy_code]. But that still requires a lot of fiddly implementation work.
That's what i meant it is impossible to do in Rust. From that point of view, Rust is a low level procedural language, but expressing any kind of business logic it is almost as high level as Haskell or Java.
But if we focus on error detection, then Rust is the highest level of any other PL. For example Java or Python are too low level when an error occurs. That high level of error detection is paid of course, and that is by longer compilation times.
If i had a wish though, i would wish Rust had as good closures as Haskell or Lisp.