#### 11.2.9 shadow [Function]

`shadow` symbol-names &optional package ⇒ t

#### Arguments and Values::

symbol-names—a designator for a list of string designators.

package—a package designator.

The default is the current package.

#### Description::

shadow assures that symbols with names given by symbol-names are present in the package.

Specifically, package is searched for symbols with the names supplied by symbol-names.

For each such name, if a corresponding symbol is not present in package (directly, not by inheritance), then a corresponding symbol is created with that name, and inserted into package as an internal symbol. The corresponding symbol, whether pre-existing or newly created, is then added, if not already present, to the shadowing symbols list of package.

#### Examples::

     (package-shadowing-symbols (make-package 'temp)) ⇒  NIL
     (find-symbol 'car 'temp) ⇒  CAR, :INHERITED
     (shadow 'car 'temp) ⇒  T
     (find-symbol 'car 'temp) ⇒  TEMP::CAR, :INTERNAL
     (package-shadowing-symbols 'temp) ⇒  (TEMP::CAR)

     (make-package 'test-1) ⇒  #<PACKAGE "TEST-1">
     (intern "TEST" (find-package 'test-1)) ⇒  TEST-1::TEST, NIL
     (shadow 'test-1::test (find-package 'test-1)) ⇒  T
     (shadow 'TEST (find-package 'test-1)) ⇒  T
     (assert (not (null (member 'test-1::test (package-shadowing-symbols
                                                (find-package 'test-1))))))

     (make-package 'test-2) ⇒  #<PACKAGE "TEST-2">
     (intern "TEST" (find-package 'test-2)) ⇒  TEST-2::TEST, NIL
     (export 'test-2::test (find-package 'test-2)) ⇒  T
     (use-package 'test-2 (find-package 'test-1))    ;should not error

#### Side Effects::

shadow changes the state of the package system in such a way that the package consistency rules do not hold across the change.

#### Affected By::

Current state of the package system.

#### See Also::

package-shadowing-symbols , Package Concepts

#### Notes::

If a symbol with a name in symbol-names already exists in package, but by inheritance, the inherited symbol becomes shadowed_3 by a newly created internal symbol.