Implement *package* special var; package overhaul.

* eval.c (load): Rebind *package* in the local dynamic
environment already established for the sake of *load-path*.
By doing this we cause *package* to be restored to its
prior value, which allows the loaded file to alter it.
Common Lisp works this way.
(eval_init): Register *package* variable, with the
user package as its default value.

* lib.c (package_s): New symbol variable.
(intern, rehome_sym): Default the package argument to the
current package, not to user_package.
(get_user_package, get_system_package, get_keyword_package):
Functions removed.
(get_current_package): New function.
(obj_print_impl): Revise symbol printing. Keyword and
uninterned symbols are printed with : and #: prefixes.
The remainder are printed with a package prefix if their
home package isn't the current package.

* lib.h (keyword_package, user_package, system_package): These
macros are just straight aliases for the global
variables, not going through the lookup mechanism,
which was pointless.
(cur_package): New macro.
(package_s): Declared.
(get_current_package): Declared.

* lisplib.c (lisplib_try_load): Establish a local
dynamic environment, and bind the *package* variable
to the user package which the library modules expect.

* parser.c (find_matching_syms, provide_completions):
Treat unqualified symbols in the current package
rather than user package.

* parser.y (sym_helper): Intern unqualified symbols
in the current package, not user package.

* txr.1: Document that the variables user-package,
system-package and keyword-package should not be modified.
Document the *package* special variable, and that intern and
rehome-sym default their package argument to its value. (Here
we get rid of wrong references to the undocumented variable
*user-package*).

1 files changed, 14 insertions, 5 deletions

diff --git a/lisplib.c b/lisplib.c
index 46514d3b..97cdedb9 100644
--- a/lisplib.c
+++ b/lisplib.c
@@ -29,9 +29,11 @@
 #include <wchar.h>
 #include <dirent.h>
 #include <stdarg.h>
+#include <signal.h>
 #include "config.h"
 #include "lib.h"
 #include "eval.h"
+#include "signal.h"
 #include "stream.h"
 #include "hash.h"
 #include "gc.h"
@@ -443,9 +445,16 @@ void lisplib_init(void)
 val lisplib_try_load(val sym)
 {
   val fun = gethash(dl_table, sym);
-  debug_state_t ds;
-  return if2(fun, (ds = debug_set_state(opt_dbg_autoload ? 0 : -1,
-                                        opt_dbg_autoload),
-                   funcall(fun),
-                   debug_restore_state(ds), t));
+
+  if (fun) {
+     debug_state_t ds = debug_set_state(opt_dbg_autoload ? 0 : -1, opt_dbg_autoload);
+     val saved_dyn_env = dyn_env;
+     dyn_env = make_env(nil, nil, dyn_env);
+     env_vbind(dyn_env, package_s, user_package);
+     funcall(fun);
+     dyn_env = saved_dyn_env;
+     debug_restore_state(ds);
+     return t;
+  }
+  return nil;
 }