Question

Rewrite the equivalent with let (let* ((x 2) (y x)) (* x y))

Answer 1

The student is asking to rewrite a Lisp expression that uses let* with let, which isn't directly possible due to scope differences between let and let* in binding variables.

Step-by-step explanation:

The question is asking to rewrite an expression in the Lisp programming language using the let* special form. The given code (let* ((x 2) (y x)) (* x y)) can't be equivalently rewritten using just let because let* allows for sequential bindings where the value of the first variable x is available when binding the second variable y. In a let expression, all bindings are done in parallel, so the x in the y binding wouldn't have the value of 2 yet. To illustrate, here's a non-equivalent let expression: (let ((x 2) (y x)) (* x y)), which would result in an error or undefined behavior for y because x has not been bound within its scope.