More sensible LayoutRoot

library/src/layout/mod.rs

@@ -49,20 +49,25 @@ use crate::text::{
 #[capability]
 pub trait LayoutRoot {
     /// Layout into one frame per page.
-    fn layout_root(&self, world: Tracked<dyn World>) -> SourceResult<Vec<Frame>>;
+    fn layout_root(
+        &self,
+        world: Tracked<dyn World>,
+        styles: StyleChain,
+    ) -> SourceResult<Vec<Frame>>;
 }
 
 impl LayoutRoot for Content {
     #[comemo::memoize]
-    fn layout_root(&self, world: Tracked<dyn World>) -> SourceResult<Vec<Frame>> {
-        let styles = StyleChain::with_root(&world.config().styles);
+    fn layout_root(
+        &self,
+        world: Tracked<dyn World>,
+        styles: StyleChain,
+    ) -> SourceResult<Vec<Frame>> {
         let scratch = Scratch::default();
-
         let mut builder = Builder::new(world, &scratch, true);
         builder.accept(self, styles)?;
-
         let (doc, shared) = builder.into_doc(styles)?;
-        doc.layout(world, shared)
+        doc.layout_root(world, shared)
     }
 }
 

library/src/lib.rs

@@ -154,7 +154,7 @@ pub fn styles() -> StyleMap {
 /// Construct the standard lang item mapping.
 pub fn items() -> LangItems {
     LangItems {
-        root: |world, content| content.layout_root(world),
+        root: |content, world, styles| content.layout_root(world, styles),
         em: |styles| styles.get(text::TextNode::SIZE),
         dir: |styles| styles.get(text::TextNode::DIR),
         space: || text::SpaceNode.pack(),

library/src/structure/doc.rs

@@ -1,13 +1,16 @@
-use crate::layout::PageNode;
+use crate::layout::{LayoutRoot, PageNode};
 use crate::prelude::*;
 
 /// A sequence of page runs.
 #[derive(Hash)]
 pub struct DocNode(pub StyleVec<PageNode>);
 
-impl DocNode {
+#[node(LayoutRoot)]
+impl DocNode {}
+
+impl LayoutRoot for DocNode {
     /// Layout the document into a sequence of frames, one per page.
-    pub fn layout(
+    fn layout_root(
         &self,
         world: Tracked<dyn World>,
         styles: StyleChain,

src/lib.rs

@@ -49,7 +49,7 @@ use comemo::{Prehashed, Track};
 use crate::diag::{FileResult, SourceResult};
 use crate::font::{Font, FontBook};
 use crate::frame::Frame;
-use crate::model::{LangItems, Route, Scope, StyleMap};
+use crate::model::{LangItems, Route, Scope, StyleChain, StyleMap};
 use crate::syntax::{Source, SourceId};
 use crate::util::Buffer;
 
@@ -62,10 +62,12 @@ pub fn typeset(
     world: &(dyn World + 'static),
     main: SourceId,
 ) -> SourceResult<Vec<Frame>> {
-    crate::model::set_lang_items(world.config().items);
+    let config = world.config();
+    crate::model::set_lang_items(config.items);
     let route = Route::default();
     let module = model::eval(world.track(), route.track(), main)?;
-    item!(root)(world.track(), &module.content)
+    let styles = StyleChain::with_root(&config.styles);
+    item!(root)(&module.content, world.track(), styles)
 }
 
 /// The environment in which typesetting occurs.

src/model/items.rs

@@ -42,8 +42,11 @@ macro_rules! item {
 #[derive(Copy, Clone)]
 pub struct LangItems {
     /// The root layout function.
-    pub root:
-        fn(world: Tracked<dyn World>, document: &Content) -> SourceResult<Vec<Frame>>,
+    pub root: fn(
+        content: &Content,
+        world: Tracked<dyn World>,
+        styles: StyleChain,
+    ) -> SourceResult<Vec<Frame>>,
     /// Access the em size.
     pub em: fn(StyleChain) -> Abs,
     /// Access the text direction.