Streamlining exception handling macros a little bit.

* eval.c (op_unwind_protect): Use uw_simple_catch_begin,
and remove the uw_catch (exsym, exvals) clause. Put
explicit braces around the unwind code even though it
is only one statement.

* match.c (do_txeval): Got rid of empty uw_unwind clause.
This is not needed any longer.
(v_try): Got rid of explicit uw_do_unwind calls.

* unwind.h (uw_simple_catch_begin): New macro.
(uw_do_unwind): Macro removed.
(uw_catch): Added goto uw_unwind_label at the front.
This way if the previous clause falls through,
control goes to the unwind logic.
(uw_unwind): Got rid of initial break. Previous
clause should fall through to unwind logic,
whether it is the main clause, or one of the catches.
(uw_catch_end): Default case aborts, because
we don't expect this.

1 files changed, 3 insertions, 6 deletions

diff --git a/eval.c b/eval.c
index f67b21af..e7475f9b 100644
--- a/eval.c
+++ b/eval.c
@@ -668,16 +668,13 @@ static val op_unwind_protect(val form, val env)
   val cleanup_forms = rest(rest(form));
   val result = nil;
 
-  uw_catch_begin(nil, exsym, exvals);
+  uw_simple_catch_begin;
 
   result = eval(prot_form, env, prot_form);
 
-  uw_do_unwind;
-
-  uw_catch (exsym, exvals);
-
-  uw_unwind
+  uw_unwind {
     eval_progn(cleanup_forms, env, cleanup_forms);
+  }
 
   uw_catch_end;