In Lisp-like and functional languages, introduces a list of local variables, each (possibly optionally) with its initial value. It is illegal to refer to any of the new variables while calculating their initial values (letrec lets you do that), though in Haskell it is legal (its
let is actually
LET is a special form in Common Lisp, Scheme, Clojure and other Lisp dialects which introduces a list of local variables as pairs of name-value bindings, for use within its body. For instance, in this expression:
(let ((variable1 (+ 1 1))) variable1)
variable1 gets bound to the
2 value, and the whole expression returns
2 as a result.