From dc18c3d017e1367d56884349a0889ef77a5cab6d Mon Sep 17 00:00:00 2001
From: yhirose <yuji.hirose.bug@gmail.com>
Date: Sun, 31 Jul 2022 07:16:45 -0400
Subject: [PATCH] Fix #237

---
 peglib.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/peglib.h b/peglib.h
index 47dd3da..6be2b14 100644
--- a/peglib.h
+++ b/peglib.h
@@ -1576,7 +1576,7 @@ class Cut : public Ope, public std::enable_shared_from_this<Cut> {
 public:
   size_t parse_core(const char * /*s*/, size_t /*n*/, SemanticValues & /*vs*/,
                     Context &c, std::any & /*dt*/) const override {
-    c.cut_stack.back() = true;
+    if (!c.cut_stack.empty()) { c.cut_stack.back() = true; }
     return 0;
   }