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ANSI Common Lisp  11 Packages 11.2 Dictionary of Packages
| 11.2.15 unintern |
Function |
- Syntax:
-
unintern
symbol &optional package
 generalized-boolean
- Arguments and Values:
-
symbol - a symbol.
package - a package designator.
The default is the current package.
generalized-boolean - a generalized boolean.
- Description:
-
unintern removes symbol from package.
If symbol is present in package, it is
removed from package and also from package's
shadowing symbols list if it is present there. If package is the
home package for symbol, symbol is made to have no
home package.
Symbol may continue to be accessible
in package by inheritance.
Use of unintern can result in a symbol
that has no
recorded home package,
but that in fact is accessible in some package.
Common Lisp does not check for this pathological case,
and such symbols
are always printed preceded by #:.
unintern returns true if it removes symbol, and nil otherwise.
- Examples:
-
(in-package "COMMON-LISP-USER") #<PACKAGE "COMMON-LISP-USER">
(setq temps-unpack (intern "UNPACK" (make-package 'temp))) TEMP::UNPACK
(unintern temps-unpack 'temp) T
(find-symbol "UNPACK" 'temp) NIL, NIL
temps-unpack #:UNPACK
- Side Effects:
-
unintern changes the state of the
package system in such a way that the consistency rules do not hold
across the change.
- Affected By:
-
Current state of the package system.
- Exceptional Situations:
-
Giving a shadowing symbol to unintern
can uncover a name conflict that had
previously been resolved by the shadowing. If package A uses packages
B and C, A contains a shadowing symbol x, and B and C each contain external
symbols named x, then removing the shadowing symbol x
from A will reveal a name
conflict between b:x and c:x if those two symbols are distinct.
In this case unintern will signal an error.
- See Also:
-
Section 11.1 Package Concepts
- Allegro CL Implementation Details:
-
None.
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