PLN CDR draft: Issue 9

1. Issue 9 (Empty package local name)

1.1. Description

It is not clear whether it should be allowed to use the empty string "" as a local nickname, and in the case it is allowed, whether it should affect the keyword symbol syntax :xxxx.

1.2. Examples

(defpackage #:foo
  (:use #:cl)
  (:local-nicknames ("" #:cl)))

(in-package #:foo)

(package-name (symbol-package ':*package*))
; => "KEYWORD"  (sbcl, ccl, ecl, abcl, clasp, lispworks)
; => "COMMON-LISP"  (acl)

(package-name (symbol-package '||:*package*))
; => "KEYWORD"  (ecl, clasp, lispworks)
; => "COMMON-LISP"  (sbcl, ccl, acl)
; abcl errors

1.3. Current behavior

sbcl, ccl: :xxxx is read as a keyword; ||:xxxx is read as a symbol in the package named or nicknamed "".

ecl, clasp, lispworks: Both ||:xxxx and :xxxx are read as a keyword.

acl:

Both :xxxx and ||:xxxx are read as a symbol in the package named or nicknamed "" which is a global nickname for the #:KEYWORD package, but can be shadowed by a local nickname.

abcl: :xxxx is read as a keyword; ||:xxxx syntax cannot be read (attemts result in an error).

1.4. Proposal ALLOW-KEEP-KEYWORDS

The "" local nickname should be explicitely allowed. :xxxx should be always read as a keyword regardless of package names or nicknames. ||:xxxx should be read as a symbol in the package named or nicknamed by "".

1.5. Proposal ALLOW-FUN

The "" local nickname should be explicitely allowed. Both :xxxx and ||:xxxx should be read as a symbol in the package named or nicknamed by "".