component generator

examples/benchmark.rs

@@ -17,7 +17,7 @@ pub fn main() {
 
             let handle = thread::spawn(move || {
                 let res = engine
-                    .run(BenchmarkApp(items))
+                    .run(BenchmarkApp { items })
                     .expect("Failed to run engine");
 
                 tx.send((items, res)).expect("Failed to send result");
@@ -41,16 +41,14 @@ pub fn main() {
     }
 }
 
-struct BenchmarkApp(pub usize);
+#[component]
+fn BenchmarkApp(cx: &Arc<Context>, items: &usize) -> View {
+    let items = items.clone();
 
-impl ComponentImpl for BenchmarkApp {
-    fn call(&self, cx: &Arc<Context>) -> View {
-        let items = self.0.clone();
-        rsx! {
-            for _ in (0..items) {
-                "Hello, world!"
-            }
+    rsx! {
+        for _ in (0..items) {
+            "Hello, world!"
         }
-        .view(cx.clone())
     }
+    .view(cx.clone())
 }

examples/hello_world.rs

@@ -4,16 +4,13 @@ use osui::prelude::*;
 
 pub fn main() {
     let engine = Console::new();
-    engine.run(App).expect("Failed to run engine");
+    engine.run(App {}).expect("Failed to run engine");
 }
 
-struct App;
-
-impl ComponentImpl for App {
-    fn call(&self, cx: &Arc<Context>) -> View {
-        rsx! {
-            "Hello, world!"
-        }
-        .view(cx.clone())
+#[component]
+fn App(cx: &Arc<Context>) -> View {
+    rsx! {
+        "Hello World"
     }
+    .view(cx.clone())
 }

examples/simple_benchmark.rs

@@ -4,7 +4,7 @@ use osui::prelude::*;
 
 pub fn main() {
     let engine = Benchmark::new(Console::new());
-    let benchmark_result = engine.run(App).expect("Failed to run engine");
+    let benchmark_result = engine.run(App {}).expect("Failed to run engine");
     println!("Avg: {} μs", benchmark_result.average);
     println!("Min: {} μs", benchmark_result.min);
     println!("Max: {} μs", benchmark_result.max);
@@ -12,13 +12,10 @@ pub fn main() {
     println!("Tot Render: {} μs", benchmark_result.total_render);
 }
 
-struct App;
-
-impl ComponentImpl for App {
-    fn call(&self, cx: &Arc<Context>) -> View {
-        rsx! {
-            "Hello, world!"
-        }
-        .view(cx.clone())
+#[component]
+fn App(cx: &Arc<Context>) -> View {
+    rsx! {
+        "Hello, world!"
     }
+    .view(cx.clone())
 }

macros/src/emit.rs

@@ -51,14 +51,14 @@ fn emit_node_scope(node: &RsxNode) -> TokenStream {
         RsxNode::Text(_) => {
             let emit = emit_node(node);
             quote! {
-                r.static_scope(|scope| {#emit});
+                r.static_scope(move |scope| {#emit});
             }
         }
 
         RsxNode::Component(_) => {
             let emit = emit_node(node);
             quote! {
-                r.static_scope(|scope| {#emit});
+                r.static_scope(move |scope| {#emit});
             }
         }
 

macros/src/lib.rs

@@ -1,10 +1,111 @@
 use proc_macro::TokenStream;
+use quote::quote;
+use syn::{FnArg, ItemFn, Pat, ReturnType, Type, parse_macro_input};
 
 mod emit;
 mod parse;
 
 #[proc_macro]
 pub fn rsx(input: TokenStream) -> TokenStream {
-    let ast = syn::parse_macro_input!(input as parse::RsxRoot);
+    let ast = parse_macro_input!(input as parse::RsxRoot);
     emit::emit_rsx(ast).into()
 }
+
+#[proc_macro_attribute]
+pub fn component(_attr: TokenStream, item: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(item as ItemFn);
+
+    let name = &input.sig.ident;
+    let vis = &input.vis;
+    let body = &input.block;
+
+    let return_ty = match &input.sig.output {
+        ReturnType::Type(_, ty) => ty,
+        _ => {
+            return syn::Error::new_spanned(&input.sig, "component must return View")
+                .to_compile_error()
+                .into();
+        }
+    };
+
+    let mut inputs = input.sig.inputs.iter();
+
+    // ---- First param must be cx ----
+    let cx = match inputs.next() {
+        Some(FnArg::Typed(pat)) => pat,
+        _ => {
+            return syn::Error::new_spanned(&input.sig, "first argument must be cx: &Arc<Context>")
+                .to_compile_error()
+                .into();
+        }
+    };
+
+    let cx_ident = match &*cx.pat {
+        Pat::Ident(id) => &id.ident,
+        _ => unreachable!(),
+    };
+
+    let cx_ty = &cx.ty;
+
+    // ---- Remaining params are props ----
+    let mut struct_fields = Vec::new();
+    let mut render_params = Vec::new();
+    let mut call_args = Vec::new();
+
+    for arg in inputs {
+        let FnArg::Typed(pat) = arg else { continue };
+
+        let ident = match &*pat.pat {
+            Pat::Ident(id) => &id.ident,
+            _ => {
+                return syn::Error::new_spanned(pat, "unsupported prop pattern")
+                    .to_compile_error()
+                    .into();
+            }
+        };
+
+        // Strip leading &
+        let owned_ty = match &*pat.ty {
+            Type::Reference(r) => &r.elem,
+            ty => ty,
+        };
+
+        struct_fields.push(quote! {
+            pub #ident: #owned_ty
+        });
+
+        render_params.push(quote! {
+            #ident: &#owned_ty
+        });
+
+        call_args.push(quote! {
+            &self.#ident
+        });
+    }
+
+    let expanded = quote! {
+        #vis struct #name {
+            #(#struct_fields,)*
+        }
+
+        impl #name {
+            pub fn component(
+                #cx_ident: #cx_ty,
+                #(#render_params,)*
+            ) -> #return_ty {
+                #body
+            }
+        }
+
+        impl ComponentImpl for #name {
+            fn call(&self, cx: &std::sync::Arc<Context>) -> #return_ty {
+                Self::component(
+                    cx,
+                    #(#call_args,)*
+                )
+            }
+        }
+    };
+
+    expanded.into()
+}

src/lib.rs

@@ -14,7 +14,7 @@ pub mod prelude {
     pub use crate::render::*;
     pub use crate::state::*;
     pub use crate::View;
-    pub use osui_macros::rsx;
+    pub use osui_macros::{component, rsx};
 }
 
 pub type View = Arc<dyn Fn(&mut DrawContext) + Send + Sync>;