On Tue, Jan 29, 2013 at 6:39 PM, Peter Enerccio <enerccio@gmail.com> wrote:
Well I tried the shadowing import, compiles fine, but when attempting to load that fas, it will throw redefinition error

Sorry for answering so late, but I just started to scan for unread emails.

The problem with your code is that SHADOWING-IMPORT is importing the CL:OPEN symbol into your package Thus you are redefining CL:OPEN.

What you should instead do is define your I/O package and define a symbol OPEN in it and SHADOWING-IMPORT it from _other_ packages.

(defpackage my-io
  (:shadow :open))

(defun open (...)
   ...)

(defpackage other-package
  (:use :cl :my-io)
  (:shadowing-import-from :my-io :open))

A probably simpler way to achieve the same would be to do a replacement package for CL. You would do

(defpackage :my-cl
 (:use :cl)
 (:shadow :open)
 (:export :open))

(let ((p (find-package "MY-CL")))
 (do-external-symbols (s (find-package "CL"))
  (unless (string-equal "OPEN" s)
   (export s p))))


(defpackage :my-other
  (:use :my-cl))

(print (symbol-package (find-symbol "OPEN" (find-package "MY-OTHER"))))
=> prints MY-OTHER
(print (symbol-package (find-symbol "COS" (find-package "MY-OTHER"))))
=> prints COMMON-LISP

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