Sandboxing support via *package-alist*.

* eval.c (eval_init): Register *package-alist* variable,
taking on the contents of the packages variable.

* lib.c (package_alist_s): New symbol variable.
(make_package, packagep, find_package, package_alist); Work
with dynamic package alist variable via cur_package_alist_loc
macro.
(get_current_package_alist_loc): New function.

* lib.h (cur_package_alist_loc): New macro.
(packages, package_alist_s, get_current_package_alist_loc):
Declared.

* txr.1: Documented *package-alist* along with notes about
sandboxing. Documented that the package-alist function is
now obsolescent.

1 files changed, 1 insertions, 0 deletions

diff --git a/eval.c b/eval.c
index 420e58a1..8b2ec9a2 100644
--- a/eval.c
+++ b/eval.c
@@ -5866,6 +5866,7 @@ void eval_init(void)
   reg_fun(intern(lit("make-sym"), user_package), func_n1(make_sym));
   reg_fun(intern(lit("gensym"), user_package), func_n1o(gensym, 0));
   reg_var(gensym_counter_s = intern(lit("*gensym-counter*"), user_package), zero);
+  reg_var(package_alist_s = intern(lit("*package-alist*"), user_package), packages);
   reg_var(package_s = intern(lit("*package*"), user_package), user_package_var);
   reg_fun(intern(lit("make-package"), user_package), func_n1(make_package));
   reg_fun(intern(lit("find-package"), user_package), func_n1(find_package));