#!/usr/local/bin/sbcl --script

(defmacro ->helper (form forms git)
  (if (null forms)
      form
    `(let ((,git ,form)) ,(->helper (car forms) (cdr forms) git))))

(defmacro -> (form &rest forms)
  (->helper form forms (intern (symbol-name '#:it))))

(defun square (n)
  (* n n))

(defun add1 (n)
  (1+ n))

(princ (macroexpand-1 '(-> 5 (add1 it) (square it))))