Confused by the difference between let and let* in Scheme

Question

Can anyone explain the difference simply? I don\'t think I understand the concept from the textbooks/sites I have consulted.

Answer 1

If you use let, you can't reference other bindings which appear in the same let expression.

For example, this won't work:

(let ((x 10)
      (y (+ x 6))) ; error! unbound identifier: x
  y)

But if you use let*, it is possible to refer to previous bindings which appear in the same let* expression:

(let* ((x 10)
       (y (+ x 6))) ; works fine
  y)
=> 16

It's all here in the documentation.