View plugins

examples/hello_world.rs

@@ -8,6 +8,7 @@ pub fn main() {
 #[component]
 fn App(cx: &Arc<Context>) -> View {
     rsx! {
+        impl my_center(11, 1)
         Card { content: "Hello World".to_string() }
     }
     .view(&cx)
@@ -22,3 +23,9 @@ fn Card(cx: &Arc<Context>, content: String) -> View {
     }
     .view(&cx)
 }
+
+fn my_center(ctx: &mut DrawContext, view: View, w: u16, h: u16) {
+    let (x, y) = ((ctx.area.width - w) / 2, (ctx.area.height - h) / 2);
+    let area = ctx.allocate(x, y, w, h);
+    ctx.draw_view(area, view);
+}

macros/src/emit.rs

@@ -51,6 +51,20 @@ fn emit_deps_vec(deps: &[Dep]) -> TokenStream {
     }
 }
 
+/// Emits a Vec of plugins
+fn emit_plugins(deps: &[ViewPlugin]) -> TokenStream {
+    deps.iter()
+        .map(|d| {
+            let path = &d.path;
+            if let Some(args) = &d.args {
+                quote!( #path(ctx, view #(,#args)*); )
+            } else {
+                quote!( #path(ctx, view); )
+            }
+        })
+        .collect()
+}
+
 /// Emits code for a single node within a scope
 fn emit_node_scope(node: &RsxNode) -> TokenStream {
     match node {
@@ -144,6 +158,7 @@ fn emit_node(node: &RsxNode) -> TokenStream {
         }
 
         RsxNode::Component {
+            plugins,
             path,
             props,
             children,
@@ -171,9 +186,17 @@ fn emit_node(node: &RsxNode) -> TokenStream {
                 }
             };
 
+            if plugins.len() == 0 {
                 quote! {
                     scope.child(#component_expr, None);
                 }
+            } else {
+                let plugins_emit = emit_plugins(plugins);
+
+                quote! {
+                    scope.child(#component_expr, Some(std::sync::Arc::new(|ctx, view| {#plugins_emit})));
+                }
+            }
         }
 
         RsxNode::Mount(m) => quote! {

macros/src/parse.rs

@@ -5,13 +5,14 @@
 use std::collections::HashSet;
 
 use proc_macro2::Span;
-use syn::braced;
 use syn::parse::discouraged::Speculative;
+use syn::punctuated::Punctuated;
 use syn::{
     Expr, Ident, LitStr, Pat, Path, Result, Token,
     parse::{Parse, ParseStream},
     token::Brace,
 };
+use syn::{braced, parenthesized};
 
 /// Root of an RSX expression
 pub struct RsxRoot {
@@ -45,6 +46,8 @@ pub enum RsxNode {
     Expr(Expr),
     /// Component instantiation: `Component { prop: value, ... }`
     Component {
+        /// View plugins
+        plugins: Vec<ViewPlugin>,
         /// Component path (e.g., `my_module::MyComponent`)
         path: Path,
         /// Component properties
@@ -82,6 +85,11 @@ pub struct Dep {
     pub is_dep: bool,
 }
 
+pub struct ViewPlugin {
+    pub path: Path,
+    pub args: Option<Vec<Expr>>,
+}
+
 fn parse_deps(input: ParseStream) -> Result<Vec<Dep>> {
     let mut deps = Vec::new();
 
@@ -122,6 +130,35 @@ fn parse_deps(input: ParseStream) -> Result<Vec<Dep>> {
     Ok(deps)
 }
 
+fn parse_plugins(input: ParseStream) -> Result<Vec<ViewPlugin>> {
+    let mut plugins = Vec::new();
+
+    if input.peek(Token![impl]) {
+        input.parse::<Token![impl]>()?;
+        loop {
+            let path: Path = input.parse()?;
+
+            let args = if input.peek(syn::token::Paren) {
+                let content;
+                parenthesized!(content in input);
+                let exprs = Punctuated::<Expr, Token![,]>::parse_terminated(&content)?;
+                Some(exprs.into_iter().collect())
+            } else {
+                None
+            };
+
+            plugins.push(ViewPlugin { path, args });
+
+            if !input.peek(Token![,]) {
+                break;
+            }
+            input.parse::<Token![,]>()?;
+        }
+    }
+
+    Ok(plugins)
+}
+
 impl Parse for RsxNode {
     fn parse(input: ParseStream) -> Result<Self> {
         // @{ $expr }
@@ -201,10 +238,12 @@ impl Parse for RsxNode {
 
 /// Parses Path or Path { ... } into RsxNode::Component.
 fn parse_component_invocation(input: ParseStream) -> Result<RsxNode> {
+    let plugins = parse_plugins(input)?;
     let path: Path = input.parse()?;
 
     if !input.peek(Brace) {
         return Ok(RsxNode::Component {
+            plugins,
             path,
             props: Vec::new(),
             children: Vec::new(),
@@ -217,6 +256,7 @@ fn parse_component_invocation(input: ParseStream) -> Result<RsxNode> {
     let (props, children) = parse_props_and_children(&content)?;
 
     Ok(RsxNode::Component {
+        plugins,
         path,
         props,
         children,