Here it is, "converted" for Mac:

(defun c:PF (/ dd mm p1 p2 is nk1 nk2)
  (setq dd t)
  (setq mm 5)
  ;(setq obj (vlax-get-acad-object))
  ;(setq doc (vla-get-ActiveDocument obj))
  ;(setq ms (vla-get-ModelSpace doc))
  (if (setq p1 (getpoint "\nFirstPoint:"))
    (progn
      (while dd
	(if (setq p2 (getpoint p1 "\nOtherPoint:"))
	  (progn
	    (setq ss (ssget "c" p2 p2))
	    (if	ss
	      (setq is -)
	      (setq is +)
	    )
	    (setq nk1 p1
		  nk2 (polar p1 (angle p1 p2) (is (distance p1 p2) mm))
	    )
	    ;(vla-addline ms (vlax-3d-point nk1) (vlax-3d-point nk2))
	    (command "LINE" nk1 nk2 "")
	    (setq p1 nk2)
	  )
	  (progn
	    (setq dd nil)
	  )
	)
      )
    )
  )
  (princ)
)

But I'm not sure this routine (even in "AC for Windows" variant) will give you results you need.