(defpackage #:fp
  (:use #:common-lisp)
  (:export #:fp)
  )

(in-package #:fp)

#|
Example expansions

(fp 1+ car) => #'(lambda (x) (1+ (car x)))

(fp) => #'(lambda (x) x)

(fp (> 0)) => #'(lambda (x) (> x 0))

(fp (> 0) car) => #'(lambda (x) (> (car x) 0))
|#

;;; Only handles 2 functions...

(defmacro fp (&rest forms)
  (let ((var (gensym)))
  `#'(lambda (,var) ,(expand-fp-forms var forms))))

(defun expand-fp-forms (var forms)
  (cond ((null forms) var)
        ((consp (car forms))
         (list* (caar forms)
                (expand-fp-forms var (cdr forms))
                (cdar forms)))
        (t (list (car forms)
                 (expand-fp-forms var (cdr forms))))))