From e9cbcd173d16452e21b1e0cf31c6937234407f7d Mon Sep 17 00:00:00 2001
From: James Mitchell <git@jmitchell.id.au>
Date: Sat, 20 Jun 2020 13:10:37 +1000
Subject: [PATCH] Adding IsValid to vscript

---
 sp/src/vscript/vscript_squirrel.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/sp/src/vscript/vscript_squirrel.cpp b/sp/src/vscript/vscript_squirrel.cpp
index 81c2f308..17d018cd 100644
--- a/sp/src/vscript/vscript_squirrel.cpp
+++ b/sp/src/vscript/vscript_squirrel.cpp
@@ -1067,6 +1067,14 @@ SQInteger tostring_stub(HSQUIRRELVM vm)
 	return 1;
 }
 
+SQInteger IsValid_stub(HSQUIRRELVM vm)
+{
+	ClassInstanceData* classInstanceData = nullptr;
+	sq_getinstanceup(vm, 1, (SQUserPointer*)&classInstanceData, 0);
+	sq_pushbool(vm, classInstanceData == nullptr);
+	return 1;
+}
+
 struct SquirrelSafeCheck
 {
 	SquirrelSafeCheck(HSQUIRRELVM vm, int outputCount = 0) :
@@ -1719,6 +1727,10 @@ bool SquirrelVM::RegisterClass(ScriptClassDesc_t* pClassDesc)
 	sq_newclosure(vm_, tostring_stub, 0);
 	sq_newslot(vm_, -3, SQFalse);
 
+	sq_pushstring(vm_, "IsValid", -1);
+	sq_newclosure(vm_, IsValid_stub, 0);
+	sq_newslot(vm_, -3, SQFalse);
+
 
 	for (int i = 0; i < pClassDesc->m_FunctionBindings.Count(); ++i)
 	{