use-package packages-to-use &optional package => t
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.
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.
(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
The use list of package may be modified.
Affected By: None.
Exceptional Situations: None.
unuse-package, package-use-list, Section 11.1 (Package Concepts)
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.