I actually started writing a comment about that. Teaching VHDL (my experience) to most programmers is an entertaining experience because they expect effects to be immediate, not executed collectively and simultaneously but mediated by a clock or other mechanism. So in an HDL:

  x <= y;
  y <= y * 20;

These two effects actually occur simultaneously, which is different again from what mathematically inclined learners might expect since there is still mutation. It is more akin to the common notation:

  x' = y
  y' = y * 20

Where the ' indicates the next value of x or y (as opposed to the derivative). Or perhaps:

  x_n = y_{n-1}
  y_n = y_{n-1} * 20

And many programming languages don't even have a good notion for similar parallel evaluation and assignment. Python does, with:

  x, y = y, y * 20

Common Lisp has psetf which permits this:

  (psetf x y
         y (* y 20))

Languages with pattern matching/destructuring bind are your best bet for writing this directly without needing temporary variables.