examples/lua-scripting/scripts/test.lua

@@ -90,37 +90,15 @@ function on_update()
         end
     end, Transform) ]]
 
-    ---@type number
-    local dt = world:resource(DeltaTime)
-
-    local view = View.new(Transform, WorldTransform)
+    local view = View.new(Transform, WorldTransform, Res(DeltaTime))
     local res = world:view_query(view)
 
-    for entity, transform, world_tran in res:iter() do
+    for entity, transform, world_tran, dt in res:iter() do
         print("Entity is at: " .. tostring(world_tran))
 
         transform:translate(0, 0.15 * dt, 0)
         entity:update(transform)
     end
-
-    --[[ world:view(
-        ---@param t Transform
-        function (t)
-            t:translate(0, 0.15 * dt, 0)
-            return t
-        end, Transform
-    ) ]]
-
-    --[[ world:view(
-        ---@param c Camera
-        function (c)
-            c.transform:translate(0, 0.15 * dt, 0)
-
-            print("Moving camera to: " .. tostring(c.transform))
-
-            return c
-        end, Camera
-    ) ]]
 end
 
 --[[ function on_post_update()

lyra-scripting/scripts/lua/ecs.lua

@@ -0,0 +1,6 @@
+---Create a Resource Query
+---@param resource table|userdata
+---@return ResQuery
+function Res(resource)
+    return ResQuery.new(resource)
+end

lyra-scripting/src/lua/ecs/mod.rs

@@ -0,0 +1,4 @@
+mod view;
+pub use view::*;
+
+pub mod query;

lyra-scripting/src/lua/ecs/query/mod.rs

@@ -0,0 +1,26 @@
+mod res;
+use mlua::ObjectLike;
+pub use res::*;
+
+use crate::{lua::{LuaComponent, FN_NAME_INTERNAL_ECS_QUERY_RESULT}, ScriptWorldPtr};
+
+#[derive(Clone)]
+pub struct LuaQuery {
+    query: LuaComponent
+}
+
+impl LuaQuery {
+    pub fn new(query: LuaComponent) -> Self {
+        Self {
+            query
+        }
+    }
+
+    /// Get the result of the query
+    /// 
+    /// > WARNING: ensure that the world pointer is not locked. If its locked when you call this,
+    /// you WILL cause a deadlock.
+    pub fn get_query_result(&self, world: ScriptWorldPtr) -> mlua::Result<mlua::Value> {
+        self.query.call_method(FN_NAME_INTERNAL_ECS_QUERY_RESULT, world)
+    }
+}

lyra-scripting/src/lua/ecs/query/res.rs

@@ -0,0 +1,57 @@
+use lyra_reflect::{ReflectWorldExt, RegisteredType};
+use mlua::IntoLua;
+
+use crate::{
+    lua::{LuaComponent, ReflectLuaProxy, WorldError, FN_NAME_INTERNAL_ECS_QUERY_RESULT},
+    ScriptWorldPtr,
+};
+
+#[derive(Clone)]
+pub struct LuaResQuery {
+    ty: LuaComponent,
+}
+
+impl mlua::FromLua for LuaResQuery {
+    fn from_lua(value: mlua::Value, _: &mlua::Lua) -> mlua::Result<Self> {
+        let tyname = value.type_name();
+        value
+            .as_userdata()
+            .ok_or(mlua::Error::FromLuaConversionError {
+                from: tyname,
+                to: "ResQuery".into(),
+                message: None,
+            })
+            .and_then(|ud| ud.borrow::<Self>())
+            .map(|ud| ud.clone())
+    }
+}
+
+impl mlua::UserData for LuaResQuery {
+    fn add_methods<M: mlua::UserDataMethods<Self>>(methods: &mut M) {
+        methods.add_function("new", |_, comp: LuaComponent| {
+            Ok(Self {
+                ty: comp
+            })
+        });
+
+        methods.add_method(FN_NAME_INTERNAL_ECS_QUERY_RESULT, |lua, this, world: ScriptWorldPtr| {
+            let mut world = world.write();
+            let reflect = this.ty.reflect_type()?;
+
+            let res = reflect.reflect_branch.as_resource_unchecked();
+            if let Some(res_ptr) = res.reflect_ptr(&mut world) {
+                let reg_type = world
+                    .get_type::<RegisteredType>(reflect.reflect_branch.reflect_type_id())
+                    .expect("Resource is not type registered!");
+                let proxy = reg_type
+                    .get_data::<ReflectLuaProxy>()
+                    .expect("Type does not have ReflectLuaProxy as a TypeData");
+
+                (proxy.fn_as_lua)(lua, res_ptr.cast()).and_then(|ud| ud.into_lua(lua))
+            } else {
+                // if the resource is not found in the world, return nil
+                Ok(mlua::Value::Nil)
+            }
+        });
+    }
+}

lyra-scripting/src/lua/ecs/view.rs

@@ -1,12 +1,13 @@
 use std::{cell::RefCell, ptr::NonNull, rc::Rc, sync::Arc};
 
 use lyra_ecs::{query::dynamic::{DynamicViewState, QueryDynamicType}, Entity};
+use lyra_reflect::List;
 use mlua::{FromLuaMulti, IntoLua, IntoLuaMulti, ObjectLike};
 use tracing::debug;
 
-use crate::{lua::{WorldError, FN_NAME_INTERNAL_REFLECT_TYPE}, ScriptBorrow, ScriptWorldPtr};
+use crate::{lua::{LuaComponent, LuaEntityRef, ReflectedIteratorOwned, TypeLookup, WorldError, FN_NAME_INTERNAL_ECS_QUERY_RESULT, FN_NAME_INTERNAL_REFLECT_TYPE}, ScriptBorrow, ScriptWorldPtr};
 
-use super::{LuaEntityRef, ReflectedIteratorOwned, TypeLookup};
+use super::query::LuaQuery;
 
 #[derive(Clone)]
 enum ViewQueryItem {
@@ -37,6 +38,34 @@ impl ViewQueryItem {
         matches!(self, ViewQueryItem::Function(_))
     }
 
+    /// Returns `true` if the QueryItem has a function of `name`.
+    /// 
+    /// Returns `false` if self is a function.
+    pub fn has_function(&self, name: &str) -> mlua::Result<bool> {
+        match self {
+            Self::UserData(ud) => {
+                ud.get::<mlua::Value>(name).map(|v| !v.is_nil())
+            },
+            Self::Table(t) => {
+                t.contains_key(name)
+            },
+            Self::Function(_) => Ok(false),
+        }
+    }
+
+    pub fn is_query(&self) -> mlua::Result<bool> {
+        self.has_function(FN_NAME_INTERNAL_ECS_QUERY_RESULT)
+    }
+
+    /// Clone self into a [`LuaComponent`].
+    pub fn as_component(&self) -> Option<LuaComponent> {
+        match self.clone() {
+            ViewQueryItem::UserData(ud) => Some(LuaComponent::UserData(ud)),
+            ViewQueryItem::Table(t) => Some(LuaComponent::Table(t)),
+            ViewQueryItem::Function(_) => None
+        }
+    }
+
     /* pub fn get_lookup(&self) -> Option<Res<TypeLookup>> {
         match self {
 
@@ -77,7 +106,9 @@ impl mlua::UserData for View {
 pub struct ViewResult {
     world: ScriptWorldPtr,
     items: Vec<ViewQueryItem>,
-    query_iter: Arc<atomic_refcell::AtomicRefCell<ReflectedIteratorOwned>>,
+    reflect_iter: Arc<atomic_refcell::AtomicRefCell<ReflectedIteratorOwned>>,
+    /// The queries and the index they would be inserted in the result.
+    queries: Vec<(LuaQuery, u32)>,
     reg_key: Arc<atomic_refcell::AtomicRefCell<Option<mlua::RegistryKey>>>,
 }
 
@@ -88,8 +119,15 @@ impl ViewResult {
         let items = view.items.clone();
         let w = world.read();
         let mut view = DynamicViewState::new();
+        let mut queries = vec![];
 
         for (idx, comp) in items.iter().enumerate() {
+            if comp.is_query()? {
+                // Unwrap is safe since `is_query` ensures that the component is convertible.
+                queries.push((LuaQuery::new(comp.as_component().unwrap()), idx as u32));
+                continue;
+            }
+
             match comp {
                 ViewQueryItem::Table(t) => {
                     let name: String = t.get(mlua::MetaMethod::Type.name())?;
@@ -141,13 +179,14 @@ impl ViewResult {
         Ok(Self {
             world,
             items,
-            query_iter: Arc::new(atomic_refcell::AtomicRefCell::new(reflected_iter)),
+            reflect_iter: Arc::new(atomic_refcell::AtomicRefCell::new(reflected_iter)),
+            queries,
             reg_key: Arc::new(atomic_refcell::AtomicRefCell::new(None)),
         })
     }
 
     fn next(&mut self, lua: &mlua::Lua) -> Result<Option<(Entity, mlua::MultiValue)>, mlua::Error> {
-        let mut query_iter = self.query_iter.borrow_mut();
+        let mut query_iter = self.reflect_iter.borrow_mut();
         if let Some(row) = query_iter.next_lua(lua) {
             let r = row
                 .row
@@ -196,12 +235,38 @@ impl mlua::UserData for ViewResult {
                 
                 if let Some(key) = key_mut.as_ref() {
                     let mut this = lua.registry_value::<Self>(&key)?;
-                    let v = this.next(lua)?;
 
-                    match v {
+                    let mut query_vals = vec![];
+                    let mut query_allows = true;
+                    for (query, i) in &this.queries {
+                        let qres = query.get_query_result(this.world.clone())?;
+                        if let Some(val) = qres.as_boolean() {
+                            if val {
+                                query_allows = false;
+                                break;
+                            }
+                        } else if qres.is_nil() {
+                            query_allows = false;
+                            break;
+                        }
+
+                        query_vals.push((qres, *i));
+                    }
+
+                    if !query_allows {
+                        return mlua::Value::Nil.into_lua_multi(lua);
+                    }
+
+                    match this.next(lua)? {
                         Some((en, mut vals)) => {
                             let lua_en = LuaEntityRef::new(this.world, en)
                                 .into_lua(lua)?;
+
+                            // insert query values to the result row
+                            for (qval, qi) in query_vals {
+                                vals.insert(qi as _, qval);
+                            }
+
                             vals.push_front(lua_en);
                             Ok(vals)
                         },

lyra-scripting/src/lua/entity_ref.rs

@@ -2,11 +2,11 @@ use std::{any::TypeId, sync::Arc};
 
 use lyra_ecs::{Entity, World};
 use lyra_reflect::TypeRegistry;
-use mlua::IntoLua;
+use mlua::{IntoLua, ObjectLike};
 
-use crate::ScriptWorldPtr;
+use crate::{ScriptBorrow, ScriptWorldPtr};
 
-use super::{reflect_user_data, ReflectLuaProxy, TypeLookup};
+use super::{reflect_user_data, Error, ReflectLuaProxy, TypeLookup, FN_NAME_INTERNAL_REFLECT_TYPE};
 
 #[derive(Clone)]
 pub enum LuaComponent {
@@ -55,6 +55,46 @@ impl LuaComponent {
             }
         }
     }
+
+    /// Call the internal reflect type function and return the result.
+    /// 
+    /// This calls the [`FN_NAME_INTERNAL_REFLECT_TYPE`] function on the Component.
+    pub fn reflect_type(&self) -> Result<ScriptBorrow, Error> {
+        self.call_function(FN_NAME_INTERNAL_REFLECT_TYPE, ())
+            .map_err(|_| Error::Reflect)
+    }
+
+    /// Call a Lua function on the Component.
+    /// 
+    /// This is a helper function so you don't have to match on the component.
+    pub fn call_function<R: mlua::FromLuaMulti>(&self, name: &str, args: impl mlua::IntoLuaMulti) -> mlua::Result<R> {
+        match self {
+            LuaComponent::UserData(ud) => ud.call_function(name, args),
+            LuaComponent::Table(t) => t.call_function(name, args),
+        }
+    }
+
+    /// Call a Lua method on the Component.
+    /// 
+    /// This is a helper function so you don't have to match on the component.
+    pub fn call_method<R: mlua::FromLuaMulti>(&self, name: &str, args: impl mlua::IntoLuaMulti) -> mlua::Result<R> {
+        match self {
+            LuaComponent::UserData(ud) => ud.call_method(name, args),
+            LuaComponent::Table(t) => t.call_method(name, args),
+        }
+    }
+
+    /// Returns `true` if the Component has a function of `name`.
+    pub fn has_function(&self, name: &str) -> mlua::Result<bool> {
+        match self {
+            LuaComponent::UserData(ud) => {
+                ud.get::<mlua::Value>(name).map(|v| !v.is_nil())
+            },
+            LuaComponent::Table(t) => {
+                t.contains_key(name)
+            },
+        }
+    }
 }
 
 /// Reference to an Entity for Lua

lyra-scripting/src/lua/mod.rs

@@ -18,8 +18,7 @@ pub mod wrappers;
 pub mod proxy;
 pub use proxy::*;
 
-mod view;
-pub use view::*;
+pub mod ecs;
 
 mod entity_ref;
 pub use entity_ref::*;
@@ -48,7 +47,9 @@ pub enum Error {
     #[error("{0}")]
     Mlua(#[from] mlua::Error),
     #[error("unimplemented: {0}")]
-    Unimplemented(String)
+    Unimplemented(String),
+    #[error("Error calling internal reflection type")]
+    Reflect,
 }
 
 /* impl Into<mlua::Error> for Error {
@@ -92,6 +93,16 @@ pub const FN_NAME_INTERNAL_REFLECT_TYPE: &str = "__lyra_internal_reflect_type";
 /// method to return data**.
 pub const FN_NAME_INTERNAL_REFLECT: &str = "__lyra_internal_reflect";
 
+/// Name of a Lua function to retrieve the query result from a Userdata, or Table.
+/// 
+/// This function must return a Lua value and take in a single argument: [`ScriptWorldPtr`].
+/// If `nil` is returned, the query in a [`View`](crate::lua::ecs::View) will not provide any
+/// results.\
+/// If it returns a boolean, the result will act as a filter, and the value will not be in
+/// the result.\
+/// Any other value will be included in the result.
+pub const FN_NAME_INTERNAL_ECS_QUERY_RESULT: &str = "__lyra_internal_ecs_query_result";
+
 /// Name of a Lua function implemented for Userdata types that can be made into components.
 /// 
 /// This is used for types that can be converted into components. When implementing this function,

lyra-scripting/src/lua/providers/ecs.rs

@@ -1,7 +1,7 @@
 use lyra_ecs::ResourceObject;
 use lyra_reflect::Reflect;
 
-use crate::{lua::{wrappers::*, LuaContext, LuaWrapper, RegisterLuaType, View, FN_NAME_INTERNAL_REFLECT, FN_NAME_INTERNAL_REFLECT_TYPE}, ScriptApiProvider, ScriptBorrow, ScriptData, ScriptDynamicBundle, ScriptWorldPtr};
+use crate::{lua::{ecs::{query::LuaResQuery, View}, wrappers::*, LuaContext, LuaWrapper, RegisterLuaType, FN_NAME_INTERNAL_REFLECT, FN_NAME_INTERNAL_REFLECT_TYPE}, ScriptApiProvider, ScriptBorrow, ScriptData, ScriptDynamicBundle, ScriptWorldPtr};
 
 //fn register_lua_proxy::<T: 
 
@@ -35,6 +35,8 @@ impl ScriptApiProvider for LyraEcsApiProvider {
         // load enums
         let bytes = include_str!("../../../scripts/lua/enums.lua");
         ctx.load(bytes).exec().unwrap();
+        let bytes = include_str!("../../../scripts/lua/ecs.lua");
+        ctx.load(bytes).exec().unwrap();
 
         let globals = ctx.globals();
         globals.set("World", ctx.create_proxy::<ScriptWorldPtr>()?)?;
@@ -43,6 +45,7 @@ impl ScriptApiProvider for LyraEcsApiProvider {
         globals.set("ActionHandler", ctx.create_proxy::<LuaActionHandler>()?)?;
         globals.set("Window", ctx.create_proxy::<LuaWindow>()?)?;
         globals.set("View", ctx.create_proxy::<View>()?)?;
+        globals.set("ResQuery", ctx.create_proxy::<LuaResQuery>()?)?;
 
         expose_comp_table_wrapper::<LuaCamera>(&ctx, &globals, "Camera")?;
         expose_comp_table_wrapper::<LuaFreeFlyCamera>(&ctx, &globals, "FreeFlyCamera")?;

lyra-scripting/src/lua/world.rs

@@ -10,7 +10,7 @@ use lyra_resource::ResourceManager;
 use mlua::{IntoLua, ObjectLike};
 
 use super::{
-    reflect_user_data, wrappers::{LuaResHandleToComponent, LuaWrappedEventProxy}, Error, ReflectLuaProxy, ReflectedIterator, TypeLookup, View, ViewResult, FN_NAME_INTERNAL_AS_COMPONENT, FN_NAME_INTERNAL_REFLECT, FN_NAME_INTERNAL_REFLECT_TYPE
+    reflect_user_data, wrappers::{LuaResHandleToComponent, LuaWrappedEventProxy}, Error, ReflectLuaProxy, ReflectedIterator, TypeLookup, ecs::{View, ViewResult}, FN_NAME_INTERNAL_AS_COMPONENT, FN_NAME_INTERNAL_REFLECT, FN_NAME_INTERNAL_REFLECT_TYPE
 };
 
 impl mlua::FromLua for ScriptEntity {