From 2ddafc2239d07c222d63c9fc6c4d98eb29f4711c Mon Sep 17 00:00:00 2001
From: Alex Shinn <ashinn@users.noreply.github.com>
Date: Sat, 12 Dec 2009 17:29:54 +0900
Subject: [PATCH] recovering gracefully from out-of-stack-space errors

---
 eval.c               | 6 ++++--
 include/chibi/sexp.h | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/eval.c b/eval.c
index 6f478fea..87e76051 100644
--- a/eval.c
+++ b/eval.c
@@ -1313,8 +1313,10 @@ sexp sexp_vm (sexp ctx, sexp proc) {
     goto make_call;
   case OP_CALL:
 #if USE_CHECK_STACK
-    if (top+16 >= SEXP_INIT_STACK_SIZE)
-      errx(70, "out of stack space at %ld", top);
+    if (top+16 >= SEXP_INIT_STACK_SIZE) {
+      _ARG1 = sexp_global(ctx, SEXP_G_OOS_ERROR);
+      goto end_loop;
+    }
 #endif
     i = sexp_unbox_fixnum(_WORD0);
     tmp1 = _ARG1;
diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index 7e4a1a10..1b487a54 100644
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -668,7 +668,8 @@ enum sexp_context_globals {
 #if ! USE_GLOBAL_SYMBOLS
   SEXP_G_SYMBOLS,
 #endif
-  SEXP_G_OOM_ERROR,
+  SEXP_G_OOM_ERROR,             /* out of memory exception object */
+  SEXP_G_OOS_ERROR,             /* out of stack exception object */
   SEXP_G_QUOTE_SYMBOL,
   SEXP_G_QUASIQUOTE_SYMBOL,
   SEXP_G_UNQUOTE_SYMBOL,