let

Recursive lexical binding form.

let introduces lexical bindings. It is similar to Scheme’s letrec.

Syntax

(let (⟨binding⟩...)
  ⟨body⟩...)

;; ⟨binding⟩ := ⟨declare-form⟩
;;            | (⟨var⟩ ⟨expr⟩)
;;            | ((values ⟨var⟩...) ⟨expr⟩)

Semantics

let binds recursively and in parallel.
It can introduce local helper functions as well as simple values.
If you need top-to-bottom binding order, use let*.
Bound variables may be declared with declare.
Multiple values may be destructured with values.
⟨body⟩ forms an implicit progn.

Example

(let ((declare x Integer)
      (x (+ y 1))
      (y 2))
  (+ x y))