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unexport

unexport Function

Syntax:

unexport symbols &optional package → t

Arguments and Values:

symbols—a designator for a list of symbols.

package—a package designator . The default is the current package.

Description:

unexport reverts external symbols in package to internal status; it undoes the effect of export.

unexport works only on symbols present in package, switching them back to internal status. If unexport is given a symbol that is already accessible as an internal symbol in package, it does nothing.

Examples:

(in-package "COMMON-LISP-USER") → #<PACKAGE "COMMON-LISP-USER"> 
(export (intern "CONTRABAND" (make-package ’temp)) ’temp) → T 
(find-symbol "CONTRABAND") → NIL, NIL 
(use-package ’temp) → T 
(find-symbol "CONTRABAND") → CONTRABAND, :INHERITED 
(unexport ’contraband ’temp) → T 
(find-symbol "CONTRABAND") → NIL, NIL

Side Effects:

Package system is modified.

Affected By:

Current state of the package system.

Exceptional Situations:

If unexport is given a symbol not accessible in package at all, an error of type package-error is signaled.

The consequences are undefined if package is the KEYWORD package or the COMMON-LISP package.

See Also:

export, Section 11.1 (Package Concepts)

Expanded Reference: unexport​

Basic Usage: Reverting a Symbol to Internal Status​

unexport changes an external symbol back to internal status. It undoes the effect of export.

(defpackage "SVC" (:use) (:export "PUBLIC-FN"))

(find-symbol "PUBLIC-FN" "SVC")
;; => SVC:PUBLIC-FN
;; => :EXTERNAL

(unexport (find-symbol "PUBLIC-FN" "SVC") "SVC")
;; => T

(find-symbol "PUBLIC-FN" "SVC")
;; => SVC::PUBLIC-FN
;; => :INTERNAL

Inherited Symbols Become Inaccessible After Unexport​

When a symbol is unexported, packages that were inheriting it can no longer see it.

(defpackage "LIB-U" (:use) (:export "HELPER"))
(defpackage "APP-U" (:use "LIB-U"))

(find-symbol "HELPER" "APP-U")
;; => LIB-U:HELPER
;; => :INHERITED

(unexport (find-symbol "HELPER" "LIB-U") "LIB-U")
;; => T

(find-symbol "HELPER" "APP-U")
;; => NIL
;; => NIL

Unexporting an Already-Internal Symbol is a No-Op​

(defpackage "INT-PKG" (:use))
(intern "SECRET" "INT-PKG")

(find-symbol "SECRET" "INT-PKG")
;; => INT-PKG::SECRET
;; => :INTERNAL

;; Already internal, so unexport does nothing special
(unexport (find-symbol "SECRET" "INT-PKG") "INT-PKG")
;; => T

(find-symbol "SECRET" "INT-PKG")
;; => INT-PKG::SECRET
;; => :INTERNAL

Unexporting Multiple Symbols​

unexport accepts a list of symbols.

(defpackage "MULTI-U" (:use) (:export "A" "B" "C"))
(unexport (list (find-symbol "A" "MULTI-U")
                (find-symbol "B" "MULTI-U"))
          "MULTI-U")
=> T

(find-symbol "A" "MULTI-U")
;; => MULTI-U::A
;; => :INTERNAL
(find-symbol "B" "MULTI-U")
;; => MULTI-U::B
;; => :INTERNAL
(find-symbol "C" "MULTI-U")
;; => MULTI-U:C
;; => :EXTERNAL