diff --git a/luprex/core/cpp/table.cpp b/luprex/core/cpp/table.cpp
index 41c0b3b3..07235b3f 100644
--- a/luprex/core/cpp/table.cpp
+++ b/luprex/core/cpp/table.cpp
@@ -316,6 +316,36 @@ LuaDefine(deque_nthr, "c") {
     return LS.result();
 }
 
+LuaDefine(deque_setl, "c") {
+    LuaArg deque, nn, val;
+    LuaStack LS(L, deque, nn, val);
+    int left, fill, max;
+    deque_get_info(L, deque.index(), &left, &fill, &max);
+    int n = LS.ckint(nn);
+    if ((n < 1) || (n > fill)) {
+        luaL_error(L, "invalid index");
+        return LS.result();
+    }
+    int target = (left + n - 1) & (max - 1);
+    LS.rawseti(deque, DEQUE_BASE + target, val);
+    return LS.result();
+}
+
+LuaDefine(deque_setr, "c") {
+    LuaArg deque, nn, val;
+    LuaStack LS(L, deque, nn, val);
+    int left, fill, max;
+    deque_get_info(L, deque.index(), &left, &fill, &max);
+    int n = LS.ckint(nn);
+    if ((n < 1) || (n > fill)) {
+        luaL_error(L, "invalid index");
+        return LS.result();
+    }
+    int target = (left + fill - n) & (max - 1);
+    LS.rawseti(deque, DEQUE_BASE + target, val);
+    return LS.result();
+}
+
 LuaDefine(deque_findl, "c") {
     LuaArg deque, val;
     LuaRet pos;
diff --git a/luprex/core/cpp/table.hpp b/luprex/core/cpp/table.hpp
index 315c6cd9..52d1e557 100644
--- a/luprex/core/cpp/table.hpp
+++ b/luprex/core/cpp/table.hpp
@@ -85,6 +85,11 @@ int deque_popr(lua_State *L);
 int deque_nthl(lua_State *L);
 int deque_nthr(lua_State *L);
 
+// Set (overwrite) the nth element in a deque.
+//
+int deque_setl(lua_State *L);
+int deque_setr(lua_State *L);
+
 //
 // Search a deque for a value.
 //