PLN CDR draft: Issue 1
1. Issue 1 (ADD-/REMOVE-PACKAGE-LOCAL-NICKNAME return values)
1.1. Description
Functions add-package-local-nickname and remove-package-local-nickname have
inconsistent return values.
The first one always returns the designated package, while the second one returns true (a generalized boolean) that indicates whether a nickname was removed.
Furthermore, there is no consensus among existing implementations as to what this generalized boolean represents.
In comparison,the functions use-package and unuse-package always return T,
and the functions export and unexport have the same behavior. There are also
functions unintern and delete-package which return a generalized boolean
indicating if the operation changed something, but their counterparts intern and
make-package, unlike with local nicknames, create and return an object (a
symbol or a package).
1.2. Examples
(defpackage #:foo (:use)) (defpackage #:bar (:use)) (add-package-local-nickname '#:nick '#:bar '#:foo) ; => #<PACKAGE "FOO"> (sbcl, ccl, ecl, acl, abcl, clasp, lispworks) (add-package-local-nickname '#:nick '#:bar '#:foo) ; => #<PACKAGE "FOO"> (sbcl, ccl, ecl, acl, abcl, clasp, lispworks) (remove-package-local-nickname '#:nick '#:foo) ; => T (sbcl, ccl, ecl, acl, clasp) ; => #<PACKAGE "BAR"> (abcl) ; => NIL (lispworks) (remove-package-local-nickname '#:nick '#:foo) ; => NIL (sbcl, ccl, ecl, acl, abcl, clasp, lispworks)
1.3. Current behavior
sbcl, ccl, ecl, acl, abcl, clasp, lispworks:
add-package-local-nickname always returns designated package.
sbcl, ccl, ecl, acl, clasp:
remove-package-local-nickname returns T if a nickname was removed,
and NIL otherwise.
abcl:
remove-package-local-nickname returns true if a nickname was removed, (more
specifically, it returns the package nicknamed by the removed local nickname),
and NIL otherwise.
lispworks:
remove-package-local-nickname always returns NIL.
1.4. Proposal ALWAYS-T
add-package-local-nickname should always return T.
remove-package-local-nickname should always return T.
1.5. Proposal ELIMINATE-GENERALIZED-BOOLEAN
add-package-local-nickname should return the designated package.
remove-package-local-nickname should return T if a nickname was removed and
NIL otherwise.
1.6. Proposal DESIGNATED-PACKAGE-IF-SUCCESSFUL
add-package-local-nickname should return the designated package if a new
nickname was added, and NIL otherwise.
remove-package-local-nickname should return the designated package if a
nickname was removed, and NIL otherwise.
1.7. Proposal NICKNAMED-PACKAGE-IF-SUCCESSFUL
add-package-local-nickname should return the nicknamed package if a new
nickname was added, and NIL otherwise.
remove-package-local-nickname should return the previously nicknamed package
if a nickname was removed, and NIL otherwise.