in-package name ⇒ package
| name | a string designator; not evaluated. |
| package | the package named by name. |
Causes the the package named by name to become the current package—that is, the value of *package*. If no such package already exists, an error of type package-error is signaled.
Everything in-package does is also performed at compile time if the call appears as a top level form.
The variable *package* is assigned. If the in-package form is a top level form, this assignment also occurs at compile time.
An error of type package-error is signaled if the specified package does not exist.