load: scope change for load hooks.

* eval.c (run_load_hooks): Install the given environment as dyn_env
temporarily, and don't restore it until after calling the hooks.
Thus the specified environment is now in effect when running the
hooks. Also, pass nil to lookup_var, in the spirit of the previous
commit. The fact that load_dyn_env had to be passed to lookup_var
previously, which is an anti-pattern, tells us that this scoping rule
was a code smell. If the *load-hooks* value comes from a given
dynamic environment, then those functions should be executed in
exactly that environment.

* txr.1: Documentation updated.

1 files changed, 4 insertions, 1 deletions

diff --git a/eval.c b/eval.c
index e1580641..3dbbbf03 100644
--- a/eval.c
+++ b/eval.c
@@ -4600,7 +4600,8 @@ static val me_pop_after_load(val form, val menv)
 
 void run_load_hooks(val load_dyn_env)
 {
-  val hooks_binding = lookup_var(load_dyn_env, load_hooks_s);
+  val saved_de = set_dyn_env(load_dyn_env);
+  val hooks_binding = lookup_var(nil, load_hooks_s);
   val hooks = cdr(hooks_binding);
 
   if (hooks) {
@@ -4608,6 +4609,8 @@ void run_load_hooks(val load_dyn_env)
       funcall(car(hooks));
     rplacd(hooks_binding, nil);
   }
+
+  set_dyn_env(saved_de);
 }
 
 static void run_load_hooks_atexit(void)