let+.el

let*, cl-labels, and seq-let all in one package.

Use

(let+ (x 0
       (a b c d) [1 2 3 4]
       plus ((&rest NUMS) (apply #'+ NUMS)))
  (plus x a b c d))
;=> 10

Bindings are made in order, like let*. Sequence bindings are recognized because they have a sequence on the left. Function bindings are recognized by having the tail (cdr) of a lambda.