From 4d0e977d6e7093765b7687bc8b93a45699c93cef Mon Sep 17 00:00:00 2001
From: Domain <do.main@msn.com>
Date: Sat, 23 Dec 2023 23:45:37 +0800
Subject: [PATCH 1/2] push nil into lua when possible

---
 source/lumars/state.d | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/source/lumars/state.d b/source/lumars/state.d
index 02b9a36..77d930a 100644
--- a/source/lumars/state.d
+++ b/source/lumars/state.d
@@ -688,6 +688,15 @@ struct LuaState
         import std.conv : to;
         import std.traits : isNumeric, isDynamicArray, isAssociativeArray, isDelegate, isPointer, isFunction,
                             PointerTarget, KeyType, ValueType, FieldNameTuple, TemplateOf, TemplateArgsOf;
+        
+        static if (__traits(compiles, value = null))
+        {
+            if (value is null)
+            {
+                lua_pushnil(this.handle);
+                return;
+            }
+        }
 
         static if(is(T == typeof(null)) || is(T == LuaNil))
             lua_pushnil(this.handle);
@@ -1040,6 +1049,39 @@ struct LuaState
         lua.pop(1);
     }
 
+    unittest
+    {
+        string str = null;
+        auto lua = LuaState(null);
+
+        lua.globalTable["a"] = str;
+        lua.doString("assert(a == nil)");
+
+        lua.globalTable["b"] = "";
+        lua.doString("assert(b == '')");
+
+        class C {}
+        C c = null;
+        lua.globalTable["c"] = c;
+        lua.doString("assert(c == nil)");
+
+        string[int] d;
+        lua.globalTable["d"] = d;
+        lua.doString("assert(d == nil)");
+
+        int[] e;
+        lua.globalTable["e"] = e;
+        lua.doString("assert(e == nil)");
+
+        int function() f;
+        lua.globalTable["f"] = f;
+        lua.doString("assert(f == nil)");
+
+        int delegate() g;
+        lua.globalTable["g"] = g;
+        lua.doString("assert(g == nil)");
+    }
+
     @nogc
     bool next(int index) nothrow
     {

From 406f01b06ff0ea2fb4a31491d36a630bd877d8b0 Mon Sep 17 00:00:00 2001
From: Domain <do.main@msn.com>
Date: Mon, 25 Dec 2023 15:37:06 +0800
Subject: [PATCH 2/2] Use is operator instead of assignment.

---
 source/lumars/state.d | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/lumars/state.d b/source/lumars/state.d
index 77d930a..bd96519 100644
--- a/source/lumars/state.d
+++ b/source/lumars/state.d
@@ -689,7 +689,7 @@ struct LuaState
         import std.traits : isNumeric, isDynamicArray, isAssociativeArray, isDelegate, isPointer, isFunction,
                             PointerTarget, KeyType, ValueType, FieldNameTuple, TemplateOf, TemplateArgsOf;
         
-        static if (__traits(compiles, value = null))
+        static if (__traits(compiles, value is null))
         {
             if (value is null)
             {