Content rework 2 - Electric Boogaloo (#2504)

14 files changed, 160 insertions, 111 deletions

diff --git a/crates/typst-library/src/layout/align.rs b/crates/typst-library/src/layout/align.rs
index f080f677..9c18266d 100644
--- a/crates/typst-library/src/layout/align.rs
+++ b/crates/typst-library/src/layout/align.rs
@@ -38,6 +38,9 @@ pub struct AlignElem {
 impl Show for AlignElem {
     #[tracing::instrument(name = "AlignElem::show", skip_all)]
     fn show(&self, _: &mut Vt, styles: StyleChain) -> SourceResult<Content> {
-        Ok(self.body().styled(Self::set_alignment(self.alignment(styles))))
+        Ok(self
+            .body()
+            .clone()
+            .styled(Self::set_alignment(self.alignment(styles))))
     }
 }
diff --git a/crates/typst-library/src/layout/enum.rs b/crates/typst-library/src/layout/enum.rs
index 436aacb9..8c491dca 100644
--- a/crates/typst-library/src/layout/enum.rs
+++ b/crates/typst-library/src/layout/enum.rs
@@ -107,6 +107,7 @@ pub struct EnumElem {
     /// + Numbering!
     /// ```
     #[default(Numbering::Pattern(NumberingPattern::from_str("1.").unwrap()))]
+    #[borrowed]
     pub numbering: Numbering,
 
     /// Which number to start the enumeration with.
@@ -215,7 +216,7 @@ impl Layout for EnumElem {
             ParElem::leading_in(styles).into()
         } else {
             self.spacing(styles)
-                .unwrap_or_else(|| BlockElem::below_in(styles).amount())
+                .unwrap_or_else(|| *BlockElem::below_in(styles).amount())
         };
 
         let mut cells = vec![];
@@ -238,7 +239,7 @@ impl Layout for EnumElem {
                 parents.pop();
                 content
             } else {
-                match &numbering {
+                match numbering {
                     Numbering::Pattern(pattern) => {
                         TextElem::packed(pattern.apply_kth(parents.len(), number))
                     }
@@ -254,7 +255,7 @@ impl Layout for EnumElem {
             cells.push(Content::empty());
             cells.push(resolved);
             cells.push(Content::empty());
-            cells.push(item.body().styled(Self::set_parents(Parent(number))));
+            cells.push(item.body().clone().styled(Self::set_parents(Parent(number))));
             number = number.saturating_add(1);
         }
 
@@ -301,6 +302,7 @@ cast! {
     v: Content => v.to::<Self>().cloned().unwrap_or_else(|| Self::new(v.clone())),
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Hash)]
 struct Parent(usize);
 
 cast! {
diff --git a/crates/typst-library/src/layout/flow.rs b/crates/typst-library/src/layout/flow.rs
index 1feee4b8..5c795c81 100644
--- a/crates/typst-library/src/layout/flow.rs
+++ b/crates/typst-library/src/layout/flow.rs
@@ -1,5 +1,7 @@
 use std::mem;
 
+use comemo::Prehashed;
+
 use super::{
     AlignElem, BlockElem, ColbreakElem, ColumnsElem, ParElem, PlaceElem, Spacing, VElem,
 };
@@ -18,7 +20,7 @@ use crate::visualize::{
 pub struct FlowElem {
     /// The children that will be arranges into a flow.
     #[variadic]
-    pub children: Vec<Content>,
+    pub children: Vec<Prehashed<Content>>,
 }
 
 impl Layout for FlowElem {
@@ -37,7 +39,7 @@ impl Layout for FlowElem {
         }
         let mut layouter = FlowLayouter::new(regions, styles);
 
-        for mut child in &self.children() {
+        for mut child in self.children().iter().map(|c| &**c) {
             let outer = styles;
             let mut styles = styles;
             if let Some((elem, map)) = child.to_styled() {
@@ -199,7 +201,7 @@ impl<'a> FlowLayouter<'a> {
                     rel.resolve(styles).relative_to(self.initial.y),
                     v.weakness(styles) > 0,
                 ),
-                Spacing::Fr(fr) => FlowItem::Fractional(fr),
+                Spacing::Fr(fr) => FlowItem::Fractional(*fr),
             },
         )
     }
@@ -701,7 +703,7 @@ fn find_footnotes(notes: &mut Vec<FootnoteElem>, frame: &Frame) {
         match item {
             FrameItem::Group(group) => find_footnotes(notes, &group.frame),
             FrameItem::Meta(Meta::Elem(content), _)
-                if !notes.iter().any(|note| note.0.location() == content.location()) =>
+                if !notes.iter().any(|note| note.location() == content.location()) =>
             {
                 let Some(footnote) = content.to::<FootnoteElem>() else { continue };
                 notes.push(footnote.clone());
diff --git a/crates/typst-library/src/layout/grid.rs b/crates/typst-library/src/layout/grid.rs
index 8d015782..b29adeb9 100644
--- a/crates/typst-library/src/layout/grid.rs
+++ b/crates/typst-library/src/layout/grid.rs
@@ -1,3 +1,5 @@
+use smallvec::{smallvec, SmallVec};
+
 use crate::prelude::*;
 use crate::text::TextElem;
 
@@ -66,12 +68,14 @@ pub struct GridElem {
     /// with that many `{auto}`-sized columns. Note that opposed to rows and
     /// gutters, providing a single track size will only ever create a single
     /// column.
+    #[borrowed]
     pub columns: TrackSizings,
 
     /// The row sizes.
     ///
     /// If there are more cells than fit the defined rows, the last row is
     /// repeated until there are no more cells.
+    #[borrowed]
     pub rows: TrackSizings,
 
     /// The gaps between rows & columns.
@@ -85,10 +89,12 @@ pub struct GridElem {
         let gutter = args.named("gutter")?;
         args.named("column-gutter")?.or_else(|| gutter.clone())
     )]
+    #[borrowed]
     pub column_gutter: TrackSizings,
 
     /// The gaps between rows. Takes precedence over `gutter`.
     #[parse(args.named("row-gutter")?.or_else(|| gutter.clone()))]
+    #[borrowed]
     pub row_gutter: TrackSizings,
 
     /// The contents of the grid cells.
@@ -106,12 +112,16 @@ impl Layout for GridElem {
         styles: StyleChain,
         regions: Regions,
     ) -> SourceResult<Fragment> {
+        let columns = self.columns(styles);
+        let rows = self.rows(styles);
+        let column_gutter = self.column_gutter(styles);
+        let row_gutter = self.row_gutter(styles);
+
         // Prepare grid layout by unifying content and gutter tracks.
-        let cells = self.children();
         let layouter = GridLayouter::new(
-            Axes::new(&self.columns(styles).0, &self.rows(styles).0),
-            Axes::new(&self.column_gutter(styles).0, &self.row_gutter(styles).0),
-            &cells,
+            Axes::new(&columns.0, &rows.0),
+            Axes::new(&column_gutter.0, &row_gutter.0),
+            &self.children,
             regions,
             styles,
             self.span(),
@@ -124,13 +134,13 @@ impl Layout for GridElem {
 
 /// Track sizing definitions.
 #[derive(Debug, Default, Clone, Eq, PartialEq, Hash)]
-pub struct TrackSizings(pub Vec<Sizing>);
+pub struct TrackSizings(pub SmallVec<[Sizing; 4]>);
 
 cast! {
     TrackSizings,
     self => self.0.into_value(),
-    sizing: Sizing => Self(vec![sizing]),
-    count: NonZeroUsize => Self(vec![Sizing::Auto; count.get()]),
+    sizing: Sizing => Self(smallvec![sizing]),
+    count: NonZeroUsize => Self(smallvec![Sizing::Auto; count.get()]),
     values: Array => Self(values.into_iter().map(Value::cast).collect::<StrResult<_>>()?),
 }
 
diff --git a/crates/typst-library/src/layout/hide.rs b/crates/typst-library/src/layout/hide.rs
index 7f17a7d7..af3d0631 100644
--- a/crates/typst-library/src/layout/hide.rs
+++ b/crates/typst-library/src/layout/hide.rs
@@ -1,3 +1,5 @@
+use smallvec::smallvec;
+
 use crate::prelude::*;
 
 /// Hides content without affecting layout.
@@ -22,6 +24,6 @@ pub struct HideElem {
 impl Show for HideElem {
     #[tracing::instrument(name = "HideElem::show", skip(self))]
     fn show(&self, _: &mut Vt, _: StyleChain) -> SourceResult<Content> {
-        Ok(self.body().styled(MetaElem::set_data(vec![Meta::Hide])))
+        Ok(self.body().clone().styled(MetaElem::set_data(smallvec![Meta::Hide])))
     }
 }
diff --git a/crates/typst-library/src/layout/list.rs b/crates/typst-library/src/layout/list.rs
index 34e0e6fb..18c89a24 100644
--- a/crates/typst-library/src/layout/list.rs
+++ b/crates/typst-library/src/layout/list.rs
@@ -77,6 +77,7 @@ pub struct ListElem {
     ///   - Items
     /// - Items
     /// ```
+    #[borrowed]
     #[default(ListMarker::Content(vec![TextElem::packed('•')]))]
     pub marker: ListMarker,
 
@@ -133,7 +134,7 @@ impl Layout for ListElem {
             ParElem::leading_in(styles).into()
         } else {
             self.spacing(styles)
-                .unwrap_or_else(|| BlockElem::below_in(styles).amount())
+                .unwrap_or_else(|| *BlockElem::below_in(styles).amount())
         };
 
         let depth = self.depth(styles);
@@ -148,7 +149,7 @@ impl Layout for ListElem {
             cells.push(Content::empty());
             cells.push(marker.clone());
             cells.push(Content::empty());
-            cells.push(item.body().styled(Self::set_depth(Depth)));
+            cells.push(item.body().clone().styled(Self::set_depth(Depth)));
         }
 
         let layouter = GridLayouter::new(
@@ -183,7 +184,7 @@ cast! {
 }
 
 /// A list's marker.
-#[derive(Debug, Clone, Hash)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum ListMarker {
     Content(Vec<Content>),
     Func(Func),
@@ -221,6 +222,7 @@ cast! {
     v: Func => Self::Func(v),
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Hash)]
 struct Depth;
 
 cast! {
diff --git a/crates/typst-library/src/layout/mod.rs b/crates/typst-library/src/layout/mod.rs
index 1c7c2610..d31f6841 100644
--- a/crates/typst-library/src/layout/mod.rs
+++ b/crates/typst-library/src/layout/mod.rs
@@ -46,6 +46,7 @@ pub use self::table::*;
 pub use self::terms::*;
 pub use self::transform::*;
 
+use std::borrow::Cow;
 use std::mem;
 
 use typed_arena::Arena;
@@ -242,16 +243,16 @@ fn realize_root<'a>(
     scratch: &'a Scratch<'a>,
     content: &'a Content,
     styles: StyleChain<'a>,
-) -> SourceResult<(Content, StyleChain<'a>)> {
+) -> SourceResult<(Cow<'a, Content>, StyleChain<'a>)> {
     if content.can::<dyn LayoutRoot>() && !applicable(content, styles) {
-        return Ok((content.clone(), styles));
+        return Ok((Cow::Borrowed(content), styles));
     }
 
     let mut builder = Builder::new(vt, scratch, true);
     builder.accept(content, styles)?;
     builder.interrupt_page(Some(styles), true)?;
     let (pages, shared) = builder.doc.unwrap().pages.finish();
-    Ok((DocumentElem::new(pages.to_vec()).pack(), shared))
+    Ok((Cow::Owned(DocumentElem::new(pages.to_vec()).pack()), shared))
 }
 
 /// Realize into an element that is capable of block-level layout.
@@ -261,7 +262,7 @@ fn realize_block<'a>(
     scratch: &'a Scratch<'a>,
     content: &'a Content,
     styles: StyleChain<'a>,
-) -> SourceResult<(Content, StyleChain<'a>)> {
+) -> SourceResult<(Cow<'a, Content>, StyleChain<'a>)> {
     // These elements implement `Layout` but still require a flow for
     // proper layout.
     if content.can::<dyn Layout>()
@@ -277,14 +278,14 @@ fn realize_block<'a>(
         && !content.is::<PlaceElem>()
         && !applicable(content, styles)
     {
-        return Ok((content.clone(), styles));
+        return Ok((Cow::Borrowed(content), styles));
     }
 
     let mut builder = Builder::new(vt, scratch, false);
     builder.accept(content, styles)?;
     builder.interrupt_par()?;
     let (children, shared) = builder.flow.0.finish();
-    Ok((FlowElem::new(children.to_vec()).pack(), shared))
+    Ok((Cow::Owned(FlowElem::new(children.to_vec()).pack()), shared))
 }
 
 /// Builds a document or a flow element from content.
@@ -509,7 +510,7 @@ impl<'a, 'v, 't> Builder<'a, 'v, 't> {
 /// Accepts pagebreaks and pages.
 struct DocBuilder<'a> {
     /// The page runs built so far.
-    pages: StyleVecBuilder<'a, Content>,
+    pages: StyleVecBuilder<'a, Cow<'a, Content>>,
     /// Whether to keep a following page even if it is empty.
     keep_next: bool,
     /// Whether the next page should be cleared to an even or odd number.
@@ -517,7 +518,7 @@ struct DocBuilder<'a> {
 }
 
 impl<'a> DocBuilder<'a> {
-    fn accept(&mut self, content: &Content, styles: StyleChain<'a>) -> bool {
+    fn accept(&mut self, content: &'a Content, styles: StyleChain<'a>) -> bool {
         if let Some(pagebreak) = content.to::<PagebreakElem>() {
             self.keep_next = !pagebreak.weak(styles);
             self.clear_next = pagebreak.to(styles);
@@ -528,9 +529,9 @@ impl<'a> DocBuilder<'a> {
             let elem = if let Some(clear_to) = self.clear_next.take() {
                 let mut page = page.clone();
                 page.push_clear_to(Some(clear_to));
-                page.pack()
+                Cow::Owned(page.pack())
             } else {
-                content.clone()
+                Cow::Borrowed(content)
             };
 
             self.pages.push(elem, styles);
@@ -571,7 +572,7 @@ impl<'a> FlowBuilder<'a> {
             || content.is::<MetaElem>()
             || content.is::<PlaceElem>()
         {
-            self.0.push(content.clone(), styles);
+            self.0.push(Cow::Borrowed(content), styles);
             return true;
         }
 
@@ -589,7 +590,7 @@ impl<'a> FlowBuilder<'a> {
             if !last_was_parbreak && is_tight_list {
                 let leading = ParElem::leading_in(styles);
                 let spacing = VElem::list_attach(leading.into());
-                self.0.push(spacing.pack(), styles);
+                self.0.push(Cow::Owned(spacing.pack()), styles);
             }
 
             let (above, below) = if let Some(block) = content.to::<BlockElem>() {
@@ -598,9 +599,9 @@ impl<'a> FlowBuilder<'a> {
                 (BlockElem::above_in(styles), BlockElem::below_in(styles))
             };
 
-            self.0.push(above.pack(), styles);
-            self.0.push(content.clone(), styles);
-            self.0.push(below.pack(), styles);
+            self.0.push(Cow::Owned(above.pack()), styles);
+            self.0.push(Cow::Borrowed(content), styles);
+            self.0.push(Cow::Owned(below.pack()), styles);
             return true;
         }
 
@@ -616,7 +617,7 @@ impl<'a> ParBuilder<'a> {
     fn accept(&mut self, content: &'a Content, styles: StyleChain<'a>) -> bool {
         if content.is::<MetaElem>() {
             if self.0.has_strong_elements(false) {
-                self.0.push(content.clone(), styles);
+                self.0.push(Cow::Borrowed(content), styles);
                 return true;
             }
         } else if content.is::<SpaceElem>()
@@ -627,7 +628,7 @@ impl<'a> ParBuilder<'a> {
             || content.to::<EquationElem>().map_or(false, |elem| !elem.block(styles))
             || content.is::<BoxElem>()
         {
-            self.0.push(content.clone(), styles);
+            self.0.push(Cow::Borrowed(content), styles);
             return true;
         }
 
@@ -643,7 +644,7 @@ impl<'a> ParBuilder<'a> {
 /// Accepts list / enum items, spaces, paragraph breaks.
 struct ListBuilder<'a> {
     /// The list items collected so far.
-    items: StyleVecBuilder<'a, Content>,
+    items: StyleVecBuilder<'a, Cow<'a, Content>>,
     /// Whether the list contains no paragraph breaks.
     tight: bool,
     /// Trailing content for which it is unclear whether it is part of the list.
@@ -668,7 +669,7 @@ impl<'a> ListBuilder<'a> {
                 .next()
                 .map_or(true, |first| first.func() == content.func())
         {
-            self.items.push(content.clone(), styles);
+            self.items.push(Cow::Borrowed(content), styles);
             self.tight &= self.staged.drain(..).all(|(t, _)| !t.is::<ParbreakElem>());
             return true;
         }
@@ -685,7 +686,8 @@ impl<'a> ListBuilder<'a> {
                     .iter()
                     .map(|(item, local)| {
                         let item = item.to::<ListItem>().unwrap();
-                        item.clone().with_body(item.body().styled_with_map(local.clone()))
+                        item.clone()
+                            .with_body(item.body().clone().styled_with_map(local.clone()))
                     })
                     .collect::<Vec<_>>(),
             )
@@ -697,7 +699,8 @@ impl<'a> ListBuilder<'a> {
                     .iter()
                     .map(|(item, local)| {
                         let item = item.to::<EnumItem>().unwrap();
-                        item.clone().with_body(item.body().styled_with_map(local.clone()))
+                        item.clone()
+                            .with_body(item.body().clone().styled_with_map(local.clone()))
                     })
                     .collect::<Vec<_>>(),
             )
@@ -710,9 +713,9 @@ impl<'a> ListBuilder<'a> {
                     .map(|(item, local)| {
                         let item = item.to::<TermItem>().unwrap();
                         item.clone()
-                            .with_term(item.term().styled_with_map(local.clone()))
+                            .with_term(item.term().clone().styled_with_map(local.clone()))
                             .with_description(
-                                item.description().styled_with_map(local.clone()),
+                                item.description().clone().styled_with_map(local.clone()),
                             )
                     })
                     .collect::<Vec<_>>(),
diff --git a/crates/typst-library/src/layout/page.rs b/crates/typst-library/src/layout/page.rs
index 495b390d..5f8f90c1 100644
--- a/crates/typst-library/src/layout/page.rs
+++ b/crates/typst-library/src/layout/page.rs
@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::ptr;
 use std::str::FromStr;
 
@@ -172,6 +173,7 @@ pub struct PageElem {
     /// #set text(fill: rgb("fdfdfd"))
     /// *Dark mode enabled.*
     /// ```
+    #[borrowed]
     pub fill: Option<Paint>,
 
     /// How to [number]($numbering) the pages.
@@ -188,6 +190,7 @@ pub struct PageElem {
     ///
     /// #lorem(48)
     /// ```
+    #[borrowed]
     pub numbering: Option<Numbering>,
 
     /// The alignment of the page numbering.
@@ -233,6 +236,7 @@ pub struct PageElem {
     ///
     /// #lorem(19)
     /// ```
+    #[borrowed]
     pub header: Option<Content>,
 
     /// The amount the header is raised into the top margin.
@@ -263,6 +267,7 @@ pub struct PageElem {
     ///
     /// #lorem(48)
     /// ```
+    #[borrowed]
     pub footer: Option<Content>,
 
     /// The amount the footer is lowered into the bottom margin.
@@ -286,6 +291,7 @@ pub struct PageElem {
     /// In the year 2023, we plan to take
     /// over the world (of typesetting).
     /// ```
+    #[borrowed]
     pub background: Option<Content>,
 
     /// Content in the page's foreground.
@@ -299,6 +305,7 @@ pub struct PageElem {
     /// "Weak Reject" because they did
     /// not understand our approach...
     /// ```
+    #[borrowed]
     pub foreground: Option<Content>,
 
     /// The contents of the page(s).
@@ -364,7 +371,7 @@ impl PageElem {
                 });
 
         // Realize columns.
-        let mut child = self.body();
+        let mut child = self.body().clone();
         let columns = self.columns(styles);
         if columns.get() > 1 {
             child = ColumnsElem::new(child).with_count(columns).pack();
@@ -388,25 +395,25 @@ impl PageElem {
         }
 
         let fill = self.fill(styles);
-        let foreground = self.foreground(styles);
-        let background = self.background(styles);
+        let foreground = Cow::Borrowed(self.foreground(styles));
+        let background = Cow::Borrowed(self.background(styles));
         let header_ascent = self.header_ascent(styles);
         let footer_descent = self.footer_descent(styles);
         let numbering = self.numbering(styles);
         let numbering_meta = Meta::PageNumbering(numbering.clone().into_value());
         let number_align = self.number_align(styles);
-        let mut header = self.header(styles);
-        let mut footer = self.footer(styles);
+        let mut header = Cow::Borrowed(self.header(styles));
+        let mut footer = Cow::Borrowed(self.footer(styles));
 
         // Construct the numbering (for header or footer).
-        let numbering_marginal = numbering.clone().map(|numbering| {
-            let both = match &numbering {
+        let numbering_marginal = Cow::Owned(numbering.as_ref().map(|numbering| {
+            let both = match numbering {
                 Numbering::Pattern(pattern) => pattern.pieces() >= 2,
                 Numbering::Func(_) => true,
             };
 
             let mut counter =
-                Counter::new(CounterKey::Page).display(Some(numbering), both);
+                Counter::new(CounterKey::Page).display(Some(numbering.clone()), both);
 
             // We interpret the Y alignment as selecting header or footer
             // and then ignore it for aligning the actual number.
@@ -415,12 +422,12 @@ impl PageElem {
             }
 
             counter
-        });
+        }));
 
         if matches!(number_align.y(), Some(VAlign::Top)) {
-            header = header.or(numbering_marginal);
+            header = if header.is_some() { header } else { numbering_marginal };
         } else {
-            footer = footer.or(numbering_marginal);
+            footer = if footer.is_some() { footer } else { numbering_marginal };
         }
 
         // Post-process pages.
@@ -455,7 +462,7 @@ impl PageElem {
             ] {
                 tracing::info!("Layouting {name}");
 
-                let Some(content) = marginal else { continue };
+                let Some(content) = &**marginal else { continue };
 
                 let (pos, area, align);
                 if ptr::eq(marginal, &header) {
@@ -488,14 +495,14 @@ impl PageElem {
                 }
             }
 
-            if let Some(fill) = &fill {
+            if let Some(fill) = fill {
                 frame.fill(fill.clone());
             }
 
             page_counter.visit(vt, frame)?;
 
             // Add a PDF page label if there is a numbering.
-            if let Some(num) = &numbering {
+            if let Some(num) = numbering {
                 if let Some(page_label) = num.apply_pdf(page_counter.logical()) {
                     frame.push_positionless_meta(Meta::PdfPageLabel(page_label));
                 }
@@ -657,10 +664,10 @@ pub enum Marginal {
 
 impl Marginal {
     /// Resolve the marginal based on the page number.
-    pub fn resolve(&self, vt: &mut Vt, page: usize) -> SourceResult<Content> {
+    pub fn resolve(&self, vt: &mut Vt, page: usize) -> SourceResult<Cow<'_, Content>> {
         Ok(match self {
-            Self::Content(content) => content.clone(),
-            Self::Func(func) => func.call_vt(vt, [page])?.display(),
+            Self::Content(content) => Cow::Borrowed(content),
+            Self::Func(func) => Cow::Owned(func.call_vt(vt, [page])?.display()),
         })
     }
 }
diff --git a/crates/typst-library/src/layout/par.rs b/crates/typst-library/src/layout/par.rs
index 10f78ef2..b3d5fb3e 100644
--- a/crates/typst-library/src/layout/par.rs
+++ b/crates/typst-library/src/layout/par.rs
@@ -1,3 +1,4 @@
+use comemo::Prehashed;
 use typst::eval::Tracer;
 use typst::model::DelayedErrors;
 use unicode_bidi::{BidiInfo, Level as BidiLevel};
@@ -104,7 +105,7 @@ pub struct ParElem {
     /// The paragraph's children.
     #[internal]
     #[variadic]
-    pub children: Vec<Content>,
+    pub children: Vec<Prehashed<Content>>,
 }
 
 impl Construct for ParElem {
@@ -158,12 +159,12 @@ impl ParElem {
             let children = par.children();
 
             // Collect all text into one string for BiDi analysis.
-            let (text, segments, spans) = collect(&children, &styles, consecutive)?;
+            let (text, segments, spans) = collect(children, &styles, consecutive)?;
 
             // Perform BiDi analysis and then prepare paragraph layout by building a
             // representation on which we can do line breaking without layouting
             // each and every line from scratch.
-            let p = prepare(&mut vt, &children, &text, segments, spans, styles, region)?;
+            let p = prepare(&mut vt, children, &text, segments, spans, styles, region)?;
 
             // Break the paragraph into lines.
             let lines = linebreak(&vt, &p, region.x - p.hang);
@@ -246,8 +247,6 @@ pub(crate) struct Preparation<'a> {
     pub items: Vec<Item<'a>>,
     /// The span mapper.
     pub spans: SpanMapper,
-    /// The styles shared by all children.
-    pub styles: StyleChain<'a>,
     /// Whether to hyphenate if it's the same for all children.
     pub hyphenate: Option<bool>,
     /// The text language if it's the same for all children.
@@ -258,8 +257,16 @@ pub(crate) struct Preparation<'a> {
     pub justify: bool,
     /// The paragraph's hanging indent.
     pub hang: Abs,
-    /// The CJK-latin spacing.
+    /// Whether to add spacing between CJK and Latin characters.
     pub cjk_latin_spacing: bool,
+    /// Whether font fallback is enabled for this paragraph.
+    pub fallback: bool,
+    /// The leading of the paragraph.
+    pub leading: Abs,
+    /// How to determine line breaks.
+    pub linebreaks: Smart<Linebreaks>,
+    /// The text size.
+    pub size: Abs,
 }
 
 impl<'a> Preparation<'a> {
@@ -525,15 +532,15 @@ impl<'a> Line<'a> {
 /// string-level preprocessing like case transformations.
 #[allow(clippy::type_complexity)]
 fn collect<'a>(
-    children: &'a [Content],
+    children: &'a [Prehashed<Content>],
     styles: &'a StyleChain<'a>,
     consecutive: bool,
 ) -> SourceResult<(String, Vec<(Segment<'a>, StyleChain<'a>)>, SpanMapper)> {
     let mut full = String::new();
     let mut quoter = Quoter::new();
-    let mut segments = vec![];
+    let mut segments = Vec::with_capacity(2 + children.len());
     let mut spans = SpanMapper::new();
-    let mut iter = children.iter().peekable();
+    let mut iter = children.iter().map(|c| &**c).peekable();
 
     let first_line_indent = ParElem::first_line_indent_in(*styles);
     if !first_line_indent.is_zero()
@@ -565,9 +572,9 @@ fn collect<'a>(
         } else if let Some(elem) = child.to::<TextElem>() {
             let prev = full.len();
             if let Some(case) = TextElem::case_in(styles) {
-                full.push_str(&case.apply(&elem.text()));
+                full.push_str(&case.apply(elem.text()));
             } else {
-                full.push_str(&elem.text());
+                full.push_str(elem.text());
             }
             Segment::Text(full.len() - prev)
         } else if let Some(elem) = child.to::<HElem>() {
@@ -576,7 +583,7 @@ fn collect<'a>(
             }
 
             full.push(SPACING_REPLACE);
-            Segment::Spacing(elem.amount())
+            Segment::Spacing(*elem.amount())
         } else if let Some(elem) = child.to::<LinebreakElem>() {
             let c = if elem.justify(styles) { '\u{2028}' } else { '\n' };
             full.push(c);
@@ -588,7 +595,7 @@ fn collect<'a>(
                 let lang = TextElem::lang_in(styles);
                 let region = TextElem::region_in(styles);
                 let quotes = Quotes::new(
-                    &quotes,
+                    quotes,
                     lang,
                     region,
                     SmartquoteElem::alternative_in(styles),
@@ -656,7 +663,7 @@ fn collect<'a>(
 /// contained inline-level content.
 fn prepare<'a>(
     vt: &mut Vt,
-    children: &'a [Content],
+    children: &'a [Prehashed<Content>],
     text: &'a str,
     segments: Vec<(Segment<'a>, StyleChain<'a>)>,
     spans: SpanMapper,
@@ -674,7 +681,7 @@ fn prepare<'a>(
     );
 
     let mut cursor = 0;
-    let mut items = vec![];
+    let mut items = Vec::with_capacity(segments.len());
 
     // Shape / layout the children and collect them into items.
     for (segment, styles) in segments {
@@ -727,13 +734,16 @@ fn prepare<'a>(
         bidi,
         items,
         spans,
-        styles,
         hyphenate: shared_get(styles, children, TextElem::hyphenate_in),
         lang: shared_get(styles, children, TextElem::lang_in),
         align: AlignElem::alignment_in(styles).resolve(styles).x,
         justify: ParElem::justify_in(styles),
         hang: ParElem::hanging_indent_in(styles),
         cjk_latin_spacing,
+        fallback: TextElem::fallback_in(styles),
+        leading: ParElem::leading_in(styles),
+        linebreaks: ParElem::linebreaks_in(styles),
+        size: TextElem::size_in(styles),
     })
 }
 
@@ -852,7 +862,7 @@ fn is_compatible(a: Script, b: Script) -> bool {
 /// paragraph.
 fn shared_get<T: PartialEq>(
     styles: StyleChain<'_>,
-    children: &[Content],
+    children: &[Prehashed<Content>],
     getter: fn(StyleChain) -> T,
 ) -> Option<T> {
     let value = getter(styles);
@@ -865,8 +875,8 @@ fn shared_get<T: PartialEq>(
 
 /// Find suitable linebreaks.
 fn linebreak<'a>(vt: &Vt, p: &'a Preparation<'a>, width: Abs) -> Vec<Line<'a>> {
-    let linebreaks = ParElem::linebreaks_in(p.styles).unwrap_or_else(|| {
-        if ParElem::justify_in(p.styles) {
+    let linebreaks = p.linebreaks.unwrap_or_else(|| {
+        if p.justify {
             Linebreaks::Optimized
         } else {
             Linebreaks::Simple
@@ -883,7 +893,7 @@ fn linebreak<'a>(vt: &Vt, p: &'a Preparation<'a>, width: Abs) -> Vec<Line<'a>> {
 /// lines greedily, always taking the longest possible line. This may lead to
 /// very unbalanced line, but is fast and simple.
 fn linebreak_simple<'a>(vt: &Vt, p: &'a Preparation<'a>, width: Abs) -> Vec<Line<'a>> {
-    let mut lines = vec![];
+    let mut lines = Vec::with_capacity(16);
     let mut start = 0;
     let mut last = None;
 
@@ -964,8 +974,8 @@ fn linebreak_optimized<'a>(vt: &Vt, p: &'a Preparation<'a>, width: Abs) -> Vec<L
         line: line(vt, p, 0..0, Breakpoint::Mandatory),
     }];
 
-    let em = TextElem::size_in(p.styles);
-
+    let em = p.size;
+    let mut lines = Vec::with_capacity(16);
     breakpoints(p, |end, breakpoint| {
         let k = table.len();
         let eof = end == p.bidi.text.len();
@@ -1071,7 +1081,6 @@ fn linebreak_optimized<'a>(vt: &Vt, p: &'a Preparation<'a>, width: Abs) -> Vec<L
     });
 
     // Retrace the best path.
-    let mut lines = vec![];
     let mut idx = table.len() - 1;
     while idx != 0 {
         table.truncate(idx + 1);
@@ -1151,7 +1160,7 @@ fn line<'a>(
             if hyphen || start < range.end || before.is_empty() {
                 let mut reshaped = shaped.reshape(vt, &p.spans, start..range.end);
                 if hyphen || shy {
-                    reshaped.push_hyphen(vt, TextElem::fallback_in(p.styles));
+                    reshaped.push_hyphen(vt, p.fallback);
                 }
 
                 if let Some(last_glyph) = reshaped.glyphs.last() {
@@ -1287,11 +1296,10 @@ fn finalize(
         .collect::<SourceResult<_>>()?;
 
     // Prevent orphans.
-    let leading = ParElem::leading_in(p.styles);
     if frames.len() >= 2 && !frames[1].is_empty() {
         let second = frames.remove(1);
         let first = &mut frames[0];
-        merge(first, second, leading);
+        merge(first, second, p.leading);
     }
 
     // Prevent widows.
@@ -1299,7 +1307,7 @@ fn finalize(
     if len >= 2 && !frames[len - 2].is_empty() {
         let second = frames.pop().unwrap();
         let first = frames.last_mut().unwrap();
-        merge(first, second, leading);
+        merge(first, second, p.leading);
     }
 
     Ok(Fragment::frames(frames))
diff --git a/crates/typst-library/src/layout/place.rs b/crates/typst-library/src/layout/place.rs
index 64cbd9a8..c8e83383 100644
--- a/crates/typst-library/src/layout/place.rs
+++ b/crates/typst-library/src/layout/place.rs
@@ -106,7 +106,10 @@ impl Layout for PlaceElem {
                 .at(self.span());
         }
 
-        let child = self.body().aligned(alignment.unwrap_or_else(|| Align::CENTER));
+        let child = self
+            .body()
+            .clone()
+            .aligned(alignment.unwrap_or_else(|| Align::CENTER));
 
         let pod = Regions::one(base, Axes::splat(false));
         let frame = child.layout(vt, styles, pod)?.into_frame();
diff --git a/crates/typst-library/src/layout/spacing.rs b/crates/typst-library/src/layout/spacing.rs
index 37f1ed35..88b6e2cd 100644
--- a/crates/typst-library/src/layout/spacing.rs
+++ b/crates/typst-library/src/layout/spacing.rs
@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 use crate::prelude::*;
 
 /// Inserts horizontal spacing into a paragraph.
@@ -71,7 +73,7 @@ impl Behave for HElem {
 
     fn larger(
         &self,
-        prev: &(Content, Behaviour, StyleChain),
+        prev: &(Cow<Content>, Behaviour, StyleChain),
         styles: StyleChain,
     ) -> bool {
         let Some(other) = prev.0.to::<Self>() else { return false };
@@ -173,7 +175,7 @@ impl Behave for VElem {
 
     fn larger(
         &self,
-        prev: &(Content, Behaviour, StyleChain),
+        prev: &(Cow<Content>, Behaviour, StyleChain),
         styles: StyleChain,
     ) -> bool {
         let Some(other) = prev.0.to::<Self>() else { return false };
diff --git a/crates/typst-library/src/layout/stack.rs b/crates/typst-library/src/layout/stack.rs
index 398341b2..50d1c862 100644
--- a/crates/typst-library/src/layout/stack.rs
+++ b/crates/typst-library/src/layout/stack.rs
@@ -60,7 +60,7 @@ impl Layout for StackElem {
         for child in self.children() {
             match child {
                 StackChild::Spacing(kind) => {
-                    layouter.layout_spacing(kind);
+                    layouter.layout_spacing(*kind);
                     deferred = None;
                 }
                 StackChild::Block(block) => {
@@ -68,7 +68,7 @@ impl Layout for StackElem {
                         layouter.layout_spacing(kind);
                     }
 
-                    layouter.layout_block(vt, &block, styles)?;
+                    layouter.layout_block(vt, block, styles)?;
                     deferred = spacing;
                 }
             }
@@ -79,7 +79,7 @@ impl Layout for StackElem {
 }
 
 /// A child of a stack element.
-#[derive(Hash)]
+#[derive(Clone, PartialEq, Hash)]
 pub enum StackChild {
     /// Spacing between other children.
     Spacing(Spacing),
diff --git a/crates/typst-library/src/layout/table.rs b/crates/typst-library/src/layout/table.rs
index 056b63a2..9e7da071 100644
--- a/crates/typst-library/src/layout/table.rs
+++ b/crates/typst-library/src/layout/table.rs
@@ -1,7 +1,7 @@
 use typst::eval::{CastInfo, Reflect};
 
 use crate::layout::{AlignElem, GridLayouter, TrackSizings};
-use crate::meta::{Figurable, LocalName};
+use crate::meta::Figurable;
 use crate::prelude::*;
 
 /// A table of items.
@@ -38,10 +38,12 @@ use crate::prelude::*;
 pub struct TableElem {
     /// The column sizes. See the [grid documentation]($grid) for more
     /// information on track sizing.
+    #[borrowed]
     pub columns: TrackSizings,
 
     /// The row sizes. See the [grid documentation]($grid) for more information
     /// on track sizing.
+    #[borrowed]
     pub rows: TrackSizings,
 
     /// The gaps between rows & columns. See the [grid documentation]($grid) for
@@ -51,6 +53,7 @@ pub struct TableElem {
 
     /// The gaps between columns. Takes precedence over `gutter`. See the
     /// [grid documentation]($grid) for more information on gutters.
+    #[borrowed]
     #[parse(
         let gutter = args.named("gutter")?;
         args.named("column-gutter")?.or_else(|| gutter.clone())
@@ -60,6 +63,7 @@ pub struct TableElem {
     /// The gaps between rows. Takes precedence over `gutter`. See the
     /// [grid documentation]($grid) for more information on gutters.
     #[parse(args.named("row-gutter")?.or_else(|| gutter.clone()))]
+    #[borrowed]
     pub row_gutter: TrackSizings,
 
     /// How to fill the cells.
@@ -82,6 +86,7 @@ pub struct TableElem {
     ///   [Profit:], [500 €], [1000 €], [1500 €],
     /// )
     /// ```
+    #[borrowed]
     pub fill: Celled<Option<Paint>>,
 
     /// How to align the cells' content.
@@ -99,6 +104,7 @@ pub struct TableElem {
     ///   [A], [B], [C],
     /// )
     /// ```
+    #[borrowed]
     pub align: Celled<Smart<Align>>,
 
     /// How to [stroke]($stroke) the cells.
@@ -151,16 +157,20 @@ impl Layout for TableElem {
     ) -> SourceResult<Fragment> {
         let inset = self.inset(styles);
         let align = self.align(styles);
+        let columns = self.columns(styles);
+        let rows = self.rows(styles);
+        let column_gutter = self.column_gutter(styles);
+        let row_gutter = self.row_gutter(styles);
 
-        let tracks = Axes::new(self.columns(styles).0, self.rows(styles).0);
-        let gutter = Axes::new(self.column_gutter(styles).0, self.row_gutter(styles).0);
+        let tracks = Axes::new(columns.0.as_slice(), rows.0.as_slice());
+        let gutter = Axes::new(column_gutter.0.as_slice(), row_gutter.0.as_slice());
         let cols = tracks.x.len().max(1);
         let cells: Vec<_> = self
             .children()
-            .into_iter()
+            .iter()
             .enumerate()
             .map(|(i, child)| {
-                let mut child = child.padded(inset);
+                let mut child = child.clone().padded(inset);
 
                 let x = i % cols;
                 let y = i / cols;
@@ -176,14 +186,8 @@ impl Layout for TableElem {
         let stroke = self.stroke(styles).map(Stroke::unwrap_or_default);
 
         // Prepare grid layout by unifying content and gutter tracks.
-        let layouter = GridLayouter::new(
-            tracks.as_deref(),
-            gutter.as_deref(),
-            &cells,
-            regions,
-            styles,
-            self.span(),
-        );
+        let layouter =
+            GridLayouter::new(tracks, gutter, &cells, regions, styles, self.span());
 
         // Measure the columns and layout the grid row-by-row.
         let mut layout = layouter.layout(vt)?;
@@ -321,7 +325,7 @@ impl<T: FromValue> FromValue for Celled<T> {
 }
 
 impl LocalName for TableElem {
-    fn local_name(&self, lang: Lang, _: Option<Region>) -> &'static str {
+    fn local_name(lang: Lang, _: Option<Region>) -> &'static str {
         match lang {
             Lang::ALBANIAN => "Tabel",
             Lang::ARABIC => "جدول",
diff --git a/crates/typst-library/src/layout/terms.rs b/crates/typst-library/src/layout/terms.rs
index 07f17bb0..d4262118 100644
--- a/crates/typst-library/src/layout/terms.rs
+++ b/crates/typst-library/src/layout/terms.rs
@@ -55,6 +55,7 @@ pub struct TermsElem {
     /// / Colon: A nice separator symbol.
     /// ```
     #[default(HElem::new(Em::new(0.6).into()).with_weak(true).pack())]
+    #[borrowed]
     pub separator: Content,
 
     /// The indentation of each item.
@@ -114,20 +115,20 @@ impl Layout for TermsElem {
             ParElem::leading_in(styles).into()
         } else {
             self.spacing(styles)
-                .unwrap_or_else(|| BlockElem::below_in(styles).amount())
+                .unwrap_or_else(|| *BlockElem::below_in(styles).amount())
         };
 
         let mut seq = vec![];
-        for (i, child) in self.children().into_iter().enumerate() {
+        for (i, child) in self.children().iter().enumerate() {
             if i > 0 {
                 seq.push(VElem::new(gutter).with_weakness(1).pack());
             }
             if !indent.is_zero() {
                 seq.push(HElem::new(indent.into()).pack());
             }
-            seq.push(child.term().strong());
-            seq.push(separator.clone());
-            seq.push(child.description());
+            seq.push(child.term().clone().strong());
+            seq.push((*separator).clone());
+            seq.push(child.description().clone());
         }
 
         Content::sequence(seq)