Support weak semantics in symbol packages.

A package is weak if it holds weak references to symbols,
meaning that if there are no references to a symbol other than
its entry in a weak package, it can be removed from the
package and reclaimed by the garbage collector.

* eval.c (eval_init): Update registrations for make-package
and sys:make-anon-package to reflect new optional argument.

* lib.c (make_package_common): New argument weak. If it is
true then both the hashes will have weak values.
(make_package, make_anon_package): New optional argument weak.
(obj_init): Add nil argument to calls to make_package. All the
standard packages are regular, not weak.

* lib.h (make_package, make_anon_package): Declarations
updated.

* txr.1: Documented.

1 files changed, 2 insertions, 2 deletions

diff --git a/eval.c b/eval.c
index 6f4cc7c1..fe11c763 100644
--- a/eval.c
+++ b/eval.c
@@ -6761,8 +6761,8 @@ void eval_init(void)
   reg_var(package_alist_s = intern(lit("*package-alist*"), user_package), packages);
   reg_var(package_s = intern(lit("*package*"), user_package),
           (opt_compat && opt_compat <= 190) ? user_package : public_package);
-  reg_fun(intern(lit("make-package"), user_package), func_n1(make_package));
-  reg_fun(intern(lit("make-anon-package"), system_package), func_n0(make_anon_package));
+  reg_fun(intern(lit("make-package"), user_package), func_n2o(make_package, 1));
+  reg_fun(intern(lit("make-anon-package"), system_package), func_n1o(make_anon_package, 0));
   reg_fun(intern(lit("find-package"), user_package), func_n1(find_package));
   reg_fun(intern(lit("delete-package"), user_package), func_n1(delete_package));
   reg_fun(intern(lit("merge-delete-package"), user_package), func_n2o(merge_delete_package, 1));