From 8d0807a12b750c307d78e53c073fb460832ea447 Mon Sep 17 00:00:00 2001
From: Quaternions <krakow20@gmail.com>
Date: Sun, 6 Oct 2024 16:50:40 -0700
Subject: [PATCH] hack together nil instances

---
 src/context.rs         | 19 +++++++++++++------
 src/runner/instance.rs | 14 ++++++++++----
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/context.rs b/src/context.rs
index 92b1424..3f2541f 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -47,12 +47,8 @@ impl Context{
 	}
 
 	pub fn find_services(&self)->Option<Services>{
-		Some(Services{
-			workspace:*self.dom.root().children().iter().find(|&&r|
-				self.dom.get_by_ref(r).is_some_and(|instance|instance.class=="Workspace")
-			)?,
-			game:self.dom.root_ref(),
-		})
+		//nil instances isn't real, it doesn't exist in real roblox places
+		None
 	}
 	pub fn convert_into_place(&mut self)->Services{
 		//snapshot root instances
@@ -74,6 +70,15 @@ impl Context{
 			game.properties.insert("Workspace".to_owned(),rbx_types::Variant::Ref(workspace));
 		}
 		self.dom.insert(game,InstanceBuilder::new("Lighting"));
+		// Special nonexistent class that holds instances parented to nil,
+		// which can still be referenced by scripts.
+		// Using a sentinel value as a ref because global variables are hard.
+		let nil=self.dom.insert(
+			game,InstanceBuilder::new("Nil")
+			.with_referent(
+				<Ref as std::str::FromStr>::from_str("ffffffffffffffffffffffffffffffff").unwrap()
+			)
+		);
 
 		//transfer original root instances into workspace
 		for instance in children{
@@ -83,6 +88,7 @@ impl Context{
 		Services{
 			game,
 			workspace,
+			nil,
 		}
 	}
 }
@@ -90,4 +96,5 @@ impl Context{
 pub struct Services{
 	pub game:Ref,
 	pub workspace:Ref,
+	pub nil:Ref,
 }
diff --git a/src/runner/instance.rs b/src/runner/instance.rs
index 222201a..d2a5694 100644
--- a/src/runner/instance.rs
+++ b/src/runner/instance.rs
@@ -16,9 +16,8 @@ pub fn set_globals(lua:&mlua::Lua,globals:&mlua::Table)->Result<(),mlua::Error>{
 	instance_table.raw_set("new",
 		lua.create_function(|lua,(class_name,parent):(mlua::String,Option<Instance>)|{
 			let class_name_str=&*class_name.to_str()?;
-			let parent=parent.ok_or(mlua::Error::runtime("Nil Parent not yet supported"))?;
+			let parent=parent.unwrap_or(Instance::nil());
 			dom_mut(lua,|dom|{
-				//TODO: Nil instances
 				Ok(Instance::new(dom.insert(parent.referent,InstanceBuilder::new(class_name_str))))
 			})
 		})?
@@ -91,6 +90,12 @@ impl Instance{
 	pub const fn new(referent:Ref)->Self{
 		Self{referent}
 	}
+	// Using a sentinel value as a ref for nil instances because global variables are hard.
+	pub fn nil()->Self{
+		Self{
+			referent:<Ref as std::str::FromStr>::from_str("ffffffffffffffffffffffffffffffff").unwrap()
+		}
+	}
 	pub fn get<'a>(&self,dom:&'a WeakDom)->mlua::Result<&'a rbx_dom_weak::Instance>{
 		dom.get_by_ref(self.referent).ok_or(mlua::Error::runtime("Instance missing"))
 	}
@@ -124,11 +129,12 @@ impl mlua::UserData for Instance{
 		fields.add_field_method_get("Parent",|lua,this|{
 			dom_mut(lua,|dom|{
 				let instance=this.get(dom)?;
+				//TODO: return nil when parent is Nil instances
 				Ok(Instance::new(instance.parent()))
 			})
 		});
 		fields.add_field_method_set("Parent",|lua,this,val:Option<Instance>|{
-			let parent=val.ok_or(mlua::Error::runtime("Nil Parent not yet supported"))?;
+			let parent=val.unwrap_or(Instance::nil());
 			dom_mut(lua,|dom|{
 				dom.transfer_within(this.referent,parent.referent);
 				Ok(())
@@ -218,7 +224,7 @@ impl mlua::UserData for Instance{
 		);
 		methods.add_method("Destroy",|lua,this,()|
 			dom_mut(lua,|dom|{
-				dom.destroy(this.referent);
+				dom.transfer_within(this.referent,Instance::nil().referent);
 				Ok(())
 			})
 		);