use-package (Function)

Syntax:

Arguments and Values:

packages-to-use—a designator for a list of package designators. The KEYWORD package may not be supplied.

package—a package designator. The default is the current package. The package cannot be the KEYWORD package.

Description:

use-package causes package to inherit all the external symbols of packages-to-use. The inherited symbols become accessible as internal symbols of package.

Packages-to-use are added to the use list of package if they are not there already. All external symbols in packages-to-use become accessible in package as internal symbols. use-package does not cause any new symbols to be present in package but only makes them accessible by inheritance.

use-package checks for name conflicts between the newly imported symbols and those already accessible in package. A name conflict in use-package between two external symbols inherited by package from packages-to-use may be resolved in favor of either symbol by importing one of them into package and making it a shadowing symbol.

Examples:

 (export (intern "LAND-FILL" (make-package 'trash)) 'trash) → T
 (find-symbol "LAND-FILL" (make-package 'temp)) → NIL, NIL
 (package-use-list 'temp) → (#<PACKAGE "TEMP">)
 (use-package 'trash 'temp) → T
 (package-use-list 'temp) → (#<PACKAGE "TEMP"> #<PACKAGE "TRASH">)
 (find-symbol "LAND-FILL" 'temp) → TRASH:LAND-FILL, :INHERITED

Side Effects:

The use list of package may be modified.

See Also:

unuse-package, package-use-list, Section 11.1 (Package Concepts)

Notes:

It is permissible for a package P₁

to use a package P₂

even if P₂ already uses P₁. The using of packages is not transitive, so no problem results from the apparent circularity.