Change default: PACKAGE/ADD-CHILD! previously allowed redefinition of

a package child only when the optional argument was true.  Now,
redefinition is always allowed _unless_ the optional argument is true.

Additionally, when a package is redefined, all of its child packages
are deleted.

The motivation for this change is to allow reloading of software
subsystems that use the package abstraction.  Previously, once such a
subsystem was loaded, it could not be reloaded without restarting
Scheme.

diff --git a/v7/src/runtime/packag.scm b/v7/src/runtime/packag.scm
index 1dadbcbf60e70ba6c8db9d2cbec16707745086cc..49b8c61d06ba80e16b0c141386d199da90d9815f 100644 (file)
--- a/v7/src/runtime/packag.scm
+++ b/v7/src/runtime/packag.scm
@@ -1,8 +1,8 @@
 #| -*-Scheme-*-
 
-$Id: packag.scm,v 14.25 1996/04/24 04:22:46 cph Exp $
+$Id: packag.scm,v 14.26 1998/02/11 04:50:31 cph Exp $
 
-Copyright (c) 1988-96 Massachusetts Institute of Technology
+Copyright (c) 1988-98 Massachusetts Institute of Technology
 
 This material was developed by the Scheme project at the Massachusetts
 Institute of Technology, Department of Electrical Engineering and
@@ -134,7 +134,7 @@ MIT in each case. |#
        '()
        (cons (car list) (loop (cdr list))))))
 
-(define (package/add-child! package name environment #!optional force?)
+(define (package/add-child! package name environment #!optional no-force?)
   (let ((child (package/child package name))
        (finish
         (lambda (child)
@@ -142,11 +142,12 @@ MIT in each case. |#
               (local-assignment environment package-name-tag child))
           child)))
     (if child
-       (if (and (not (default-object? force?)) force?)
-           (begin
-             (set-package/environment! child environment)
-             (finish child))
-           (error "Package already has child of given name:" package name))
+       (begin
+         (if (and (not (default-object? no-force?)) no-force?)
+             (error "Package already has child of given name:" package name))
+         (set-package/environment! child environment)
+         (set-package/children! child '())
+         (finish child))
        (let ((child (make-package package name environment)))
          (set-package/children! package
                                 (cons child (package/children package)))