From 2bdaebe8c7ad816eac546ec634f3cc2fb8950e79 Mon Sep 17 00:00:00 2001
From: Alex Shinn <alexshinn@gmail.com>
Date: Mon, 6 Jul 2020 16:20:40 +0900
Subject: [PATCH] wrap uncaught non-exceptions (issue #664)

---
 include/chibi/sexp.h | 5 +++--
 sexp.c               | 5 +++--
 vm.c                 | 3 +++
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index 975b4216..7803c08c 100644
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -597,9 +597,10 @@ struct sexp_struct {
 #define SEXP_RAWDOT SEXP_MAKE_IMMEDIATE(7) /* internal use */
 #define SEXP_STRING_OPORT SEXP_MAKE_IMMEDIATE(8)  /* internal use */
 #define SEXP_TRAMPOLINE   SEXP_MAKE_IMMEDIATE(9)  /* internal use */
-#define SEXP_ABI_ERROR    SEXP_MAKE_IMMEDIATE(10) /* internal use */
+#define SEXP_UNCAUGHT     SEXP_MAKE_IMMEDIATE(10) /* internal use */
+#define SEXP_ABI_ERROR    SEXP_MAKE_IMMEDIATE(11) /* internal use */
 #if SEXP_USE_OBJECT_BRACE_LITERALS
-#define SEXP_CLOSE_BRACE  SEXP_MAKE_IMMEDIATE(11) /* internal use */
+#define SEXP_CLOSE_BRACE  SEXP_MAKE_IMMEDIATE(12) /* internal use */
 #endif
 
 #if SEXP_USE_LIMITED_MALLOC
diff --git a/sexp.c b/sexp.c
index 2dae62f1..e39877e8 100644
--- a/sexp.c
+++ b/sexp.c
@@ -811,8 +811,9 @@ sexp sexp_print_exception_op (sexp ctx, sexp self, sexp_sint_t n, sexp exn, sexp
   sexp_gc_var2(ls, tmp);
   /* unwrap continuable exceptions */
   if (sexp_exceptionp(exn)
-      && sexp_exception_kind(exn) == sexp_global(ctx, SEXP_G_CONTINUABLE_SYMBOL)
-      && sexp_exceptionp(sexp_exception_irritants(exn))) {
+      && ((sexp_exception_kind(exn) == sexp_global(ctx, SEXP_G_CONTINUABLE_SYMBOL)
+           && sexp_exceptionp(sexp_exception_irritants(exn)))
+          || sexp_exception_kind(exn) == SEXP_UNCAUGHT)) {
     return sexp_print_exception_op(ctx, self, n, sexp_exception_irritants(exn), out);
   }
   sexp_gc_preserve2(ctx, ls, tmp);
diff --git a/vm.c b/vm.c
index 1949a0b3..7c807464 100644
--- a/vm.c
+++ b/vm.c
@@ -1121,6 +1121,9 @@ sexp sexp_apply (sexp ctx, sexp proc, sexp args) {
 #if SEXP_USE_GREEN_THREADS
       sexp_context_errorp(ctx) = 1;
 #endif
+      if (!sexp_exceptionp(_ARG1)) {
+        _ARG1 = sexp_make_exception(ctx, SEXP_UNCAUGHT, SEXP_FALSE, _ARG1, self, SEXP_FALSE);
+      }
       goto end_loop;
     }
     stack[top] = SEXP_ONE;