Earlier quoted context omitted.
https://stackoverflow.com/questions/22308071/what-is-the-dif... The difference between let and const is that once you bind a value/object to a variable using const, you can't reassign to that variable. In other words Example: const something = {}; something = 1; // Error. let somethingElse = {}; somethingElse = 100; // This is ok
Which is odd because in every other language that uses let (lisp, scheme, swift, rust, scala/kotlin val, haskell, etc.), let bindings are const and let is synonymous with const.
Let bindings in Lisp are not const. You can use `setf` (among others) to mutate the variable. For instance, this works just fine in Lisp:
(let ((x 1))
(print x) ;; => 1
(incf x)
(print x)) ;; => 2