Flexible ECS System Params (#798)

system params can be in any order, faster compiles, remove foreach

crates/bevy_app/src/app_builder.rs

@@ -4,7 +4,7 @@ use crate::{
     plugin::Plugin,
     stage, startup_stage, PluginGroup, PluginGroupBuilder,
 };
-use bevy_ecs::{FromResources, IntoQuerySystem, Resources, System, World};
+use bevy_ecs::{FromResources, IntoSystem, Resources, System, World};
 
 /// Configure [App]s using the builder pattern
 pub struct AppBuilder {

crates/bevy_asset/src/assets.rs

@@ -2,7 +2,7 @@ use crate::{
     update_asset_storage_system, Asset, AssetLoader, AssetServer, Handle, HandleId, RefChange,
 };
 use bevy_app::{prelude::Events, AppBuilder};
-use bevy_ecs::{FromResources, IntoQuerySystem, ResMut};
+use bevy_ecs::{FromResources, IntoSystem, ResMut};
 use bevy_type_registry::RegisterType;
 use bevy_utils::HashMap;
 use crossbeam_channel::Sender;

crates/bevy_asset/src/lib.rs

@@ -31,7 +31,7 @@ pub mod prelude {
 }
 
 use bevy_app::{prelude::Plugin, AppBuilder};
-use bevy_ecs::IntoQuerySystem;
+use bevy_ecs::IntoSystem;
 use bevy_type_registry::RegisterType;
 
 /// Adds support for Assets to an App. Assets are typed collections with change tracking, which are added as App Resources.

crates/bevy_diagnostic/src/frame_time_diagnostics_plugin.rs

@@ -1,7 +1,7 @@
 use crate::{Diagnostic, DiagnosticId, Diagnostics};
 use bevy_app::prelude::*;
 use bevy_core::Time;
-use bevy_ecs::{IntoQuerySystem, Res, ResMut};
+use bevy_ecs::{IntoSystem, Res, ResMut};
 
 /// Adds "frame time" diagnostic to an App, specifically "frame time", "fps" and "frame count"
 #[derive(Default)]

crates/bevy_diagnostic/src/lib.rs

@@ -18,7 +18,7 @@ impl Plugin for DiagnosticsPlugin {
         app.init_resource::<Diagnostics>();
         #[cfg(feature = "profiler")]
         {
-            use bevy_ecs::IntoQuerySystem;
+            use bevy_ecs::IntoSystem;
             app.add_resource::<Box<dyn bevy_ecs::Profiler>>(Box::new(
                 system_profiler::SystemProfiler::default(),
             ))

crates/bevy_diagnostic/src/print_diagnostics_plugin.rs

@@ -1,7 +1,7 @@
 use super::{Diagnostic, DiagnosticId, Diagnostics};
 use bevy_app::prelude::*;
 use bevy_core::{Time, Timer};
-use bevy_ecs::{IntoQuerySystem, Res, ResMut};
+use bevy_ecs::{IntoSystem, Res, ResMut};
 use std::time::Duration;
 
 /// An App Plugin that prints diagnostics to the console

crates/bevy_ecs/hecs/macros/src/lib.rs

@@ -22,7 +22,10 @@ use proc_macro::TokenStream;
 use proc_macro2::{Span, TokenStream as TokenStream2};
 use proc_macro_crate::crate_name;
 use quote::quote;
-use syn::{parse_macro_input, DeriveInput, Error, Ident, Index, Lifetime, Path, Result};
+use syn::{
+    parse::ParseStream, parse_macro_input, Data, DataStruct, DeriveInput, Error, Field, Fields,
+    Ident, Index, Lifetime, Path, Result,
+};
 
 /// Implement `Bundle` for a monomorphic struct
 ///
@@ -332,3 +335,92 @@ pub fn impl_query_set(_input: TokenStream) -> TokenStream {
 
     tokens
 }
+
+#[derive(Default)]
+struct SystemParamFieldAttributes {
+    pub ignore: bool,
+}
+
+static SYSTEM_PARAM_ATTRIBUTE_NAME: &str = "system_param";
+
+#[proc_macro_derive(SystemParam, attributes(system_param))]
+pub fn derive_system_param(input: TokenStream) -> TokenStream {
+    let ast = parse_macro_input!(input as DeriveInput);
+    let fields = match &ast.data {
+        Data::Struct(DataStruct {
+            fields: Fields::Named(fields),
+            ..
+        }) => &fields.named,
+        _ => panic!("expected a struct with named fields"),
+    };
+
+    let path_str = if crate_name("bevy").is_ok() {
+        "bevy::ecs"
+    } else {
+        "bevy_ecs"
+    };
+    let path: Path = syn::parse(path_str.parse::<TokenStream>().unwrap()).unwrap();
+
+    let field_attributes = fields
+        .iter()
+        .map(|field| {
+            (
+                field,
+                field
+                    .attrs
+                    .iter()
+                    .find(|a| *a.path.get_ident().as_ref().unwrap() == SYSTEM_PARAM_ATTRIBUTE_NAME)
+                    .map_or_else(SystemParamFieldAttributes::default, |a| {
+                        syn::custom_keyword!(ignore);
+                        let mut attributes = SystemParamFieldAttributes::default();
+                        a.parse_args_with(|input: ParseStream| {
+                            if input.parse::<Option<ignore>>()?.is_some() {
+                                attributes.ignore = true;
+                            }
+                            Ok(())
+                        })
+                        .expect("invalid 'render_resources' attribute format");
+
+                        attributes
+                    }),
+            )
+        })
+        .collect::<Vec<(&Field, SystemParamFieldAttributes)>>();
+    let mut fields = Vec::new();
+    let mut field_types = Vec::new();
+    let mut ignored_fields = Vec::new();
+    let mut ignored_field_types = Vec::new();
+    for (field, attrs) in field_attributes.iter() {
+        if attrs.ignore {
+            ignored_fields.push(field.ident.as_ref().unwrap());
+            ignored_field_types.push(&field.ty);
+        } else {
+            fields.push(field.ident.as_ref().unwrap());
+            field_types.push(&field.ty);
+        }
+    }
+
+    let generics = ast.generics;
+    let (impl_generics, ty_generics, _where_clause) = generics.split_for_impl();
+
+    let struct_name = &ast.ident;
+
+    TokenStream::from(quote! {
+        impl #impl_generics #path::SystemParam for #struct_name#ty_generics {
+            fn init(system_state: &mut #path::SystemState, world: &#path::World, resources: &mut #path::Resources) {
+                #(<#field_types>::init(system_state, world, resources);)*
+            }
+
+            unsafe fn get_param(
+                system_state: &mut #path::SystemState,
+                world: &#path::World,
+                resources: &#path::Resources,
+            ) -> Option<Self> {
+                Some(#struct_name {
+                    #(#fields: <#field_types>::get_param(system_state, world, resources)?,)*
+                    #(#ignored_fields: <#ignored_field_types>::default(),)*
+                })
+            }
+        }
+    })
+}

crates/bevy_ecs/hecs/src/lib.rs

@@ -98,4 +98,4 @@ pub use lazy_static;
 pub use query::Fetch;
 
 #[cfg(feature = "macros")]
-pub use bevy_hecs_macros::{impl_query_set, Bundle};
+pub use bevy_hecs_macros::{impl_query_set, Bundle, SystemParam};

crates/bevy_ecs/hecs/src/query.rs

@@ -296,7 +296,7 @@ impl_or_query!(Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10);
 ///     .collect::<Vec<_>>();
 /// assert_eq!(components, &[(false, 457)]);
 /// ```
-pub struct Or<T>(PhantomData<T>);
+pub struct Or<T>(pub T);
 //pub struct Or<Q1, Q2, Q3>(PhantomData<(Q1, Q2, Q3)>);
 
 #[doc(hidden)]

crates/bevy_ecs/hecs/src/world.rs

@@ -249,6 +249,7 @@ impl World {
     /// assert!(entities.contains(&(a, 123, true)));
     /// assert!(entities.contains(&(b, 456, false)));
     /// ```
+    #[inline]
     pub fn query<Q: Query>(&self) -> QueryIter<'_, Q>
     where
         Q::Fetch: ReadOnlyFetch,
@@ -281,13 +282,15 @@ impl World {
     /// assert!(entities.contains(&(a, 123, true)));
     /// assert!(entities.contains(&(b, 456, false)));
     /// ```
+    #[inline]
     pub fn query_mut<Q: Query>(&mut self) -> QueryIter<'_, Q> {
         // SAFE: unique mutable access
         unsafe { self.query_unchecked() }
     }
 
     /// Like `query`, but instead of returning a single iterator it returns a "batched iterator",
     /// where each batch is `batch_size`. This is generally used for parallel iteration.
+    #[inline]
     pub fn query_batched<Q: Query>(&self, batch_size: usize) -> BatchedIter<'_, Q>
     where
         Q::Fetch: ReadOnlyFetch,
@@ -298,6 +301,7 @@ impl World {
 
     /// Like `query`, but instead of returning a single iterator it returns a "batched iterator",
     /// where each batch is `batch_size`. This is generally used for parallel iteration.
+    #[inline]
     pub fn query_batched_mut<Q: Query>(&mut self, batch_size: usize) -> BatchedIter<'_, Q> {
         // SAFE: unique mutable access
         unsafe { self.query_batched_unchecked(batch_size) }
@@ -316,6 +320,7 @@ impl World {
     /// # Safety
     /// This does not check for mutable query correctness. To be safe, make sure mutable queries
     /// have unique access to the components they query.
+    #[inline]
     pub unsafe fn query_unchecked<Q: Query>(&self) -> QueryIter<'_, Q> {
         QueryIter::new(&self.archetypes)
     }
@@ -347,6 +352,7 @@ impl World {
     /// let (number, flag) = world.query_one::<(&i32, &bool)>(a).unwrap();
     /// assert_eq!(*number, 123);
     /// ```
+    #[inline]
     pub fn query_one<Q: Query>(
         &self,
         entity: Entity,
@@ -372,6 +378,7 @@ impl World {
     /// if *flag { *number *= 2; }
     /// assert_eq!(*number, 246);
     /// ```
+    #[inline]
     pub fn query_one_mut<Q: Query>(
         &mut self,
         entity: Entity,
@@ -387,6 +394,7 @@ impl World {
     /// # Safety
     /// This does not check for mutable query correctness. To be safe, make sure mutable queries
     /// have unique access to the components they query.
+    #[inline]
     pub unsafe fn query_one_unchecked<Q: Query>(
         &self,
         entity: Entity,
@@ -399,6 +407,7 @@ impl World {
     }
 
     /// Borrow the `T` component of `entity`
+    #[inline]
     pub fn get<T: Component>(&self, entity: Entity) -> Result<&'_ T, ComponentError> {
         unsafe {
             let loc = self.entities.get(entity)?;
@@ -414,6 +423,7 @@ impl World {
     }
 
     /// Mutably borrow the `T` component of `entity`
+    #[inline]
     pub fn get_mut<T: Component>(&mut self, entity: Entity) -> Result<Mut<'_, T>, ComponentError> {
         // SAFE: uniquely borrows world
         unsafe { self.get_mut_unchecked(entity) }
@@ -434,6 +444,7 @@ impl World {
     /// # Safety
     /// This does not check for mutable access correctness. To be safe, make sure this is the only
     /// thing accessing this entity's T component.
+    #[inline]
     pub unsafe fn get_mut_unchecked<T: Component>(
         &self,
         entity: Entity,

crates/bevy_ecs/src/lib.rs

@@ -11,10 +11,8 @@ pub use world::*;
 
 pub mod prelude {
     pub use crate::{
-        resource::{ChangedRes, FromResources, Local, OrRes, Res, ResMut, Resource, Resources},
-        system::{
-            Commands, IntoForEachSystem, IntoQuerySystem, IntoThreadLocalSystem, Query, System,
-        },
+        resource::{ChangedRes, FromResources, Local, Res, ResMut, Resource, Resources},
+        system::{Commands, IntoSystem, IntoThreadLocalSystem, Query, System},
         world::WorldBuilderSource,
         Added, Bundle, Changed, Component, Entity, Mut, Mutated, Or, QuerySet, Ref, RefMut, With,
         Without, World,