From 0dd4ae0a7ac0c247078df492469ff20b8a90c886 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Sat, 21 Aug 2021 16:38:51 +0200
Subject: [PATCH] Prune derives

---
 src/color.rs              |  42 ++++++------
 src/diag.rs               |   2 +-
 src/eval/array.rs         |  12 ++--
 src/eval/capture.rs       |   1 -
 src/eval/dict.rs          |  24 +++----
 src/eval/function.rs      |  12 ++--
 src/eval/mod.rs           | 135 ++------------------------------------
 src/eval/scope.rs         |   4 +-
 src/eval/state.rs         |   6 +-
 src/eval/str.rs           |  30 ++++-----
 src/eval/template.rs      |  18 ++---
 src/eval/value.rs         |  52 +++++++--------
 src/eval/walk.rs          | 129 ++++++++++++++++++++++++++++++++++++
 src/font.rs               |  47 ++++++-------
 src/geom/angle.rs         |  21 +++---
 src/geom/fr.rs            |  12 ++--
 src/geom/length.rs        |  16 ++---
 src/geom/linear.rs        |  12 ++--
 src/geom/relative.rs      |  12 ++--
 src/geom/sides.rs         |  16 ++---
 src/image.rs              |   3 +-
 src/layout/background.rs  |   1 -
 src/layout/constraints.rs |  10 ---
 src/layout/fixed.rs       |   3 +-
 src/layout/grid.rs        |   5 +-
 src/layout/image.rs       |   1 -
 src/layout/pad.rs         |   1 -
 src/layout/par.rs         |  15 -----
 src/layout/shaping.rs     |  87 +++++++++++-------------
 src/layout/stack.rs       |   2 -
 src/layout/tree.rs        |  60 +----------------
 src/loading/fs.rs         |   2 +-
 src/loading/mem.rs        |   2 +-
 src/loading/mod.rs        |   5 +-
 src/paper.rs              |   2 +-
 src/parse/mod.rs          |   4 +-
 src/parse/parser.rs       |  10 ---
 src/parse/scanner.rs      |   7 --
 src/parse/tokens.rs       |  11 +---
 src/source.rs             |  15 ++---
 src/syntax/ident.rs       |   2 +-
 src/syntax/node.rs        |   8 +--
 src/syntax/pretty.rs      |  16 ++---
 src/syntax/span.rs        |  42 +++++++-----
 src/syntax/token.rs       |   8 +--
 src/syntax/visit.rs       |   8 +--
 src/util/eco.rs           |  36 +++++-----
 tests/typeset.rs          |   5 +-
 48 files changed, 434 insertions(+), 540 deletions(-)
 create mode 100644 src/eval/walk.rs

diff --git a/src/color.rs b/src/color.rs
index 124c20423..bf4cf05a0 100644
--- a/src/color.rs
+++ b/src/color.rs
@@ -12,14 +12,6 @@ pub enum Color {
     Rgba(RgbaColor),
 }
 
-impl Display for Color {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        match self {
-            Self::Rgba(c) => Display::fmt(c, f),
-        }
-    }
-}
-
 impl Debug for Color {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
@@ -28,6 +20,14 @@ impl Debug for Color {
     }
 }
 
+impl Display for Color {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        match self {
+            Self::Rgba(c) => Display::fmt(c, f),
+        }
+    }
+}
+
 /// An 8-bit RGBA color.
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Serialize, Deserialize)]
 pub struct RgbaColor {
@@ -97,16 +97,6 @@ impl FromStr for RgbaColor {
     }
 }
 
-impl Display for RgbaColor {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "#{:02x}{:02x}{:02x}", self.r, self.g, self.b)?;
-        if self.a != 255 {
-            write!(f, "{:02x}", self.a)?;
-        }
-        Ok(())
-    }
-}
-
 impl Debug for RgbaColor {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         if f.alternate() {
@@ -121,18 +111,28 @@ impl Debug for RgbaColor {
     }
 }
 
+impl Display for RgbaColor {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "#{:02x}{:02x}{:02x}", self.r, self.g, self.b)?;
+        if self.a != 255 {
+            write!(f, "{:02x}", self.a)?;
+        }
+        Ok(())
+    }
+}
+
 /// The error when parsing an [`RgbaColor`] from a string fails.
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub struct ParseRgbaError;
 
-impl std::error::Error for ParseRgbaError {}
-
-impl fmt::Display for ParseRgbaError {
+impl Display for ParseRgbaError {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         f.pad("invalid color")
     }
 }
 
+impl std::error::Error for ParseRgbaError {}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/src/diag.rs b/src/diag.rs
index 90f640f6e..61432e932 100644
--- a/src/diag.rs
+++ b/src/diag.rs
@@ -22,7 +22,7 @@ pub type TypResult<T> = Result<T, Box<Vec<Error>>>;
 pub type StrResult<T> = Result<T, String>;
 
 /// An error in a source file.
-#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Serialize, Deserialize)]
+#[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct Error {
     /// The erroneous location in the source code.
     pub span: Span,
diff --git a/src/eval/array.rs b/src/eval/array.rs
index e554b11ed..acf44ab2f 100644
--- a/src/eval/array.rs
+++ b/src/eval/array.rs
@@ -137,18 +137,18 @@ impl AddAssign for Array {
     }
 }
 
-impl FromIterator<Value> for Array {
-    fn from_iter<T: IntoIterator<Item = Value>>(iter: T) -> Self {
-        Self(Rc::new(iter.into_iter().collect()))
-    }
-}
-
 impl Extend<Value> for Array {
     fn extend<T: IntoIterator<Item = Value>>(&mut self, iter: T) {
         Rc::make_mut(&mut self.0).extend(iter);
     }
 }
 
+impl FromIterator<Value> for Array {
+    fn from_iter<T: IntoIterator<Item = Value>>(iter: T) -> Self {
+        Self(Rc::new(iter.into_iter().collect()))
+    }
+}
+
 impl IntoIterator for Array {
     type Item = Value;
     type IntoIter = std::vec::IntoIter<Value>;
diff --git a/src/eval/capture.rs b/src/eval/capture.rs
index a6e543f9d..f0a2b7292 100644
--- a/src/eval/capture.rs
+++ b/src/eval/capture.rs
@@ -5,7 +5,6 @@ use crate::syntax::visit::{immutable::visit_expr, Visit};
 use crate::syntax::{Expr, Ident};
 
 /// A visitor that captures variable slots.
-#[derive(Debug)]
 pub struct CapturesVisitor<'a> {
     external: &'a Scopes<'a>,
     internal: Scopes<'a>,
diff --git a/src/eval/dict.rs b/src/eval/dict.rs
index 66baaec08..dfac04ed9 100644
--- a/src/eval/dict.rs
+++ b/src/eval/dict.rs
@@ -82,6 +82,12 @@ fn missing_key(key: &Str) -> String {
     format!("dictionary does not contain key: {}", key)
 }
 
+impl Debug for Dict {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.debug_map().entries(self.0.iter()).finish()
+    }
+}
+
 impl Display for Dict {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         f.write_char('(')?;
@@ -100,12 +106,6 @@ impl Display for Dict {
     }
 }
 
-impl Debug for Dict {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        f.debug_map().entries(self.0.iter()).finish()
-    }
-}
-
 impl Add for Dict {
     type Output = Self;
 
@@ -124,18 +124,18 @@ impl AddAssign for Dict {
     }
 }
 
-impl FromIterator<(Str, Value)> for Dict {
-    fn from_iter<T: IntoIterator<Item = (Str, Value)>>(iter: T) -> Self {
-        Self(Rc::new(iter.into_iter().collect()))
-    }
-}
-
 impl Extend<(Str, Value)> for Dict {
     fn extend<T: IntoIterator<Item = (Str, Value)>>(&mut self, iter: T) {
         Rc::make_mut(&mut self.0).extend(iter);
     }
 }
 
+impl FromIterator<(Str, Value)> for Dict {
+    fn from_iter<T: IntoIterator<Item = (Str, Value)>>(iter: T) -> Self {
+        Self(Rc::new(iter.into_iter().collect()))
+    }
+}
+
 impl IntoIterator for Dict {
     type Item = (Str, Value);
     type IntoIter = std::collections::btree_map::IntoIter<Str, Value>;
diff --git a/src/eval/function.rs b/src/eval/function.rs
index 7967090b6..57364d11d 100644
--- a/src/eval/function.rs
+++ b/src/eval/function.rs
@@ -38,6 +38,12 @@ impl Function {
     }
 }
 
+impl Debug for Function {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.debug_struct("Function").field("name", &self.0.name).finish()
+    }
+}
+
 impl Display for Function {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         f.write_str("<function")?;
@@ -49,12 +55,6 @@ impl Display for Function {
     }
 }
 
-impl Debug for Function {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        f.debug_struct("Function").field("name", &self.0.name).finish()
-    }
-}
-
 impl PartialEq for Function {
     fn eq(&self, other: &Self) -> bool {
         // We cast to thin pointers for comparison.
diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index f7a32127c..b8561a87e 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -13,6 +13,7 @@ mod scope;
 mod state;
 mod str;
 mod template;
+mod walk;
 
 pub use self::str::*;
 pub use array::*;
@@ -23,25 +24,24 @@ pub use scope::*;
 pub use state::*;
 pub use template::*;
 pub use value::*;
+pub use walk::*;
 
 use std::cell::RefMut;
 use std::collections::HashMap;
-use std::fmt::Write;
 use std::io;
 use std::mem;
 use std::path::PathBuf;
 use std::rc::Rc;
 
 use crate::diag::{At, Error, StrResult, Trace, Tracepoint, TypResult};
-use crate::geom::{Angle, Fractional, Gen, Length, Relative};
+use crate::geom::{Angle, Fractional, Length, Relative};
 use crate::image::ImageStore;
-use crate::layout::{ParChild, ParNode, StackChild, StackNode};
 use crate::loading::Loader;
 use crate::parse::parse;
 use crate::source::{SourceId, SourceStore};
 use crate::syntax::visit::Visit;
 use crate::syntax::*;
-use crate::util::{EcoString, RefMutExt};
+use crate::util::RefMutExt;
 use crate::Context;
 
 /// Evaluate a parsed source file into a module.
@@ -52,7 +52,7 @@ pub fn eval(ctx: &mut Context, source: SourceId, ast: &SyntaxTree) -> TypResult<
 }
 
 /// An evaluated module, ready for importing or instantiation.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Default, Clone)]
 pub struct Module {
     /// The top-level definitions that were bound in this module.
     pub scope: Scope,
@@ -717,128 +717,3 @@ impl Access for CallExpr {
         })
     }
 }
-
-/// Walk a syntax node and fill the currently built template.
-pub trait Walk {
-    /// Walk the node.
-    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()>;
-}
-
-impl Walk for SyntaxTree {
-    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
-        for node in self.iter() {
-            node.walk(ctx)?;
-        }
-        Ok(())
-    }
-}
-
-impl Walk for SyntaxNode {
-    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
-        match self {
-            Self::Space => ctx.template.space(),
-            Self::Linebreak(_) => ctx.template.linebreak(),
-            Self::Parbreak(_) => ctx.template.parbreak(),
-            Self::Strong(_) => {
-                ctx.template.modify(|state| state.font_mut().strong ^= true);
-            }
-            Self::Emph(_) => {
-                ctx.template.modify(|state| state.font_mut().emph ^= true);
-            }
-            Self::Text(text) => ctx.template.text(text),
-            Self::Raw(raw) => raw.walk(ctx)?,
-            Self::Heading(heading) => heading.walk(ctx)?,
-            Self::List(list) => list.walk(ctx)?,
-            Self::Enum(enum_) => enum_.walk(ctx)?,
-            Self::Expr(expr) => match expr.eval(ctx)? {
-                Value::None => {}
-                Value::Int(v) => ctx.template.text(v.to_string()),
-                Value::Float(v) => ctx.template.text(v.to_string()),
-                Value::Str(v) => ctx.template.text(v),
-                Value::Template(v) => ctx.template += v,
-                // For values which can't be shown "naturally", we print the
-                // representation in monospace.
-                other => ctx.template.monospace(other.to_string()),
-            },
-        }
-        Ok(())
-    }
-}
-
-impl Walk for RawNode {
-    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
-        if self.block {
-            ctx.template.parbreak();
-        }
-
-        ctx.template.monospace(&self.text);
-
-        if self.block {
-            ctx.template.parbreak();
-        }
-
-        Ok(())
-    }
-}
-
-impl Walk for HeadingNode {
-    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
-        let level = self.level;
-        let body = self.body.eval(ctx)?;
-
-        ctx.template.parbreak();
-        ctx.template.save();
-        ctx.template.modify(move |state| {
-            let font = state.font_mut();
-            let upscale = 1.6 - 0.1 * level as f64;
-            font.size *= upscale;
-            font.strong = true;
-        });
-        ctx.template += body;
-        ctx.template.restore();
-        ctx.template.parbreak();
-
-        Ok(())
-    }
-}
-
-impl Walk for ListItem {
-    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
-        let body = self.body.eval(ctx)?;
-        walk_item(ctx, '•'.into(), body);
-        Ok(())
-    }
-}
-
-impl Walk for EnumItem {
-    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
-        let body = self.body.eval(ctx)?;
-        let mut label = EcoString::new();
-        write!(&mut label, "{}.", self.number.unwrap_or(1)).unwrap();
-        walk_item(ctx, label, body);
-        Ok(())
-    }
-}
-
-/// Walk a list or enum item, converting it into a stack.
-fn walk_item(ctx: &mut EvalContext, label: EcoString, body: Template) {
-    ctx.template += Template::from_block(move |state| {
-        let label = ParNode {
-            dir: state.dirs.cross,
-            line_spacing: state.line_spacing(),
-            children: vec![ParChild::Text(
-                label.clone(),
-                state.aligns.cross,
-                Rc::clone(&state.font),
-            )],
-        };
-        StackNode {
-            dirs: Gen::new(state.dirs.main, state.dirs.cross),
-            children: vec![
-                StackChild::Any(label.into(), Gen::default()),
-                StackChild::Spacing((state.font.size / 2.0).into()),
-                StackChild::Any(body.to_stack(&state).into(), Gen::default()),
-            ],
-        }
-    });
-}
diff --git a/src/eval/scope.rs b/src/eval/scope.rs
index 2968ca205..0d7016873 100644
--- a/src/eval/scope.rs
+++ b/src/eval/scope.rs
@@ -12,7 +12,7 @@ use crate::util::EcoString;
 pub type Slot = Rc<RefCell<Value>>;
 
 /// A stack of scopes.
-#[derive(Debug, Default, Clone, PartialEq)]
+#[derive(Debug, Default, Clone)]
 pub struct Scopes<'a> {
     /// The active scope.
     pub top: Scope,
@@ -65,7 +65,7 @@ impl<'a> Scopes<'a> {
 }
 
 /// A map from variable names to variable slots.
-#[derive(Default, Clone, PartialEq)]
+#[derive(Default, Clone)]
 pub struct Scope {
     /// The mapping from names to slots.
     values: HashMap<EcoString, Slot>,
diff --git a/src/eval/state.rs b/src/eval/state.rs
index 760a830a9..055589152 100644
--- a/src/eval/state.rs
+++ b/src/eval/state.rs
@@ -63,7 +63,7 @@ impl Default for State {
 }
 
 /// Defines page properties.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub struct PageState {
     /// The class of this page.
     pub class: PaperClass,
@@ -220,7 +220,7 @@ impl Default for FontState {
 }
 
 /// Font family definitions.
-#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub struct FamilyState {
     /// The user-defined list of font families.
     pub list: Rc<Vec<FontFamily>>,
@@ -250,7 +250,7 @@ impl Default for FamilyState {
 }
 
 /// Defines a line that is positioned over, under or on top of text.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub struct LineState {
     /// Stroke color of the line, defaults to the text color if `None`.
     pub stroke: Option<Paint>,
diff --git a/src/eval/str.rs b/src/eval/str.rs
index 1a0e3e1f7..a358cd9fc 100644
--- a/src/eval/str.rs
+++ b/src/eval/str.rs
@@ -6,7 +6,7 @@ use crate::diag::StrResult;
 use crate::util::EcoString;
 
 /// A string value with inline storage and clone-on-write semantics.
-#[derive(Default, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[derive(Default, Clone, Eq, PartialEq, Ord, PartialOrd)]
 pub struct Str(EcoString);
 
 impl Str {
@@ -46,6 +46,20 @@ impl Str {
     }
 }
 
+impl Deref for Str {
+    type Target = str;
+
+    fn deref(&self) -> &str {
+        self.0.deref()
+    }
+}
+
+impl Debug for Str {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        Debug::fmt(&self.0, f)
+    }
+}
+
 impl Display for Str {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         f.write_char('"')?;
@@ -63,20 +77,6 @@ impl Display for Str {
     }
 }
 
-impl Debug for Str {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        Debug::fmt(&self.0, f)
-    }
-}
-
-impl Deref for Str {
-    type Target = str;
-
-    fn deref(&self) -> &str {
-        self.0.deref()
-    }
-}
-
 impl Add for Str {
     type Output = Self;
 
diff --git a/src/eval/template.rs b/src/eval/template.rs
index 2293796b7..92b3eb864 100644
--- a/src/eval/template.rs
+++ b/src/eval/template.rs
@@ -160,18 +160,18 @@ impl Template {
     }
 }
 
-impl Display for Template {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        f.pad("<template>")
-    }
-}
-
 impl Debug for Template {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         f.pad("Template { .. }")
     }
 }
 
+impl Display for Template {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.pad("<template>")
+    }
+}
+
 impl PartialEq for Template {
     fn eq(&self, other: &Self) -> bool {
         Rc::ptr_eq(&self.0, &other.0)
@@ -465,11 +465,11 @@ impl ParBuilder {
     }
 
     fn push_inner(&mut self, child: ParChild) {
-        if let ParChild::Text(curr_text, curr_props, curr_align) = &child {
-            if let Some(ParChild::Text(prev_text, prev_props, prev_align)) =
+        if let ParChild::Text(curr_text, curr_align, curr_props) = &child {
+            if let Some(ParChild::Text(prev_text, prev_align, prev_props)) =
                 self.children.last_mut()
             {
-                if prev_align == curr_align && prev_props == curr_props {
+                if prev_align == curr_align && Rc::ptr_eq(prev_props, curr_props) {
                     prev_text.push_str(&curr_text);
                     return;
                 }
diff --git a/src/eval/value.rs b/src/eval/value.rs
index 99efc2e58..5edf0362c 100644
--- a/src/eval/value.rs
+++ b/src/eval/value.rs
@@ -144,6 +144,12 @@ impl From<usize> for Value {
     }
 }
 
+impl From<RgbaColor> for Value {
+    fn from(v: RgbaColor) -> Self {
+        Self::Color(Color::Rgba(v))
+    }
+}
+
 impl From<&str> for Value {
     fn from(v: &str) -> Self {
         Self::Str(v.into())
@@ -162,12 +168,6 @@ impl From<EcoString> for Value {
     }
 }
 
-impl From<RgbaColor> for Value {
-    fn from(v: RgbaColor) -> Self {
-        Self::Color(Color::Rgba(v))
-    }
-}
-
 impl From<Dynamic> for Value {
     fn from(v: Dynamic) -> Self {
         Self::Dyn(v)
@@ -181,7 +181,7 @@ impl Dynamic {
     /// Create a new instance from any value that satisifies the required bounds.
     pub fn new<T>(any: T) -> Self
     where
-        T: Type + Debug + Display + Clone + PartialEq + 'static,
+        T: Type + Debug + Display + PartialEq + 'static,
     {
         Self(Rc::new(any))
     }
@@ -202,18 +202,18 @@ impl Dynamic {
     }
 }
 
-impl Display for Dynamic {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        Display::fmt(&self.0, f)
-    }
-}
-
 impl Debug for Dynamic {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         Debug::fmt(&self.0, f)
     }
 }
 
+impl Display for Dynamic {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        Display::fmt(&self.0, f)
+    }
+}
+
 impl PartialEq for Dynamic {
     fn eq(&self, other: &Self) -> bool {
         self.0.dyn_eq(other)
@@ -228,7 +228,7 @@ trait Bounds: Debug + Display + 'static {
 
 impl<T> Bounds for T
 where
-    T: Type + Debug + Display + Clone + PartialEq + 'static,
+    T: Type + Debug + Display + PartialEq + 'static,
 {
     fn as_any(&self) -> &dyn Any {
         self
@@ -309,12 +309,6 @@ macro_rules! primitive {
             const TYPE_NAME: &'static str = $name;
         }
 
-        impl From<$type> for Value {
-            fn from(v: $type) -> Self {
-                Value::$variant(v)
-            }
-        }
-
         impl Cast<Value> for $type {
             fn is(value: &Value) -> bool {
                 matches!(value, Value::$variant(_) $(| Value::$other(_))*)
@@ -332,6 +326,12 @@ macro_rules! primitive {
                 }
             }
         }
+
+        impl From<$type> for Value {
+            fn from(v: $type) -> Self {
+                Value::$variant(v)
+            }
+        }
     };
 }
 
@@ -342,17 +342,17 @@ macro_rules! dynamic {
             const TYPE_NAME: &'static str = $name;
         }
 
-        impl From<$type> for $crate::eval::Value {
-            fn from(v: $type) -> Self {
-                $crate::eval::Value::Dyn($crate::eval::Dynamic::new(v))
-            }
-        }
-
         castable! {
             $type: <Self as $crate::eval::Type>::TYPE_NAME,
             $($tts)*
             @this: Self => this.clone(),
         }
+
+        impl From<$type> for $crate::eval::Value {
+            fn from(v: $type) -> Self {
+                $crate::eval::Value::Dyn($crate::eval::Dynamic::new(v))
+            }
+        }
     };
 }
 
diff --git a/src/eval/walk.rs b/src/eval/walk.rs
new file mode 100644
index 000000000..4c6a1605d
--- /dev/null
+++ b/src/eval/walk.rs
@@ -0,0 +1,129 @@
+use std::fmt::Write;
+use std::rc::Rc;
+
+use super::{Eval, EvalContext, Template, Value};
+use crate::diag::TypResult;
+use crate::geom::Gen;
+use crate::layout::{ParChild, ParNode, StackChild, StackNode};
+use crate::syntax::*;
+use crate::util::EcoString;
+
+/// Walk a syntax node and fill the currently built template.
+pub trait Walk {
+    /// Walk the node.
+    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()>;
+}
+
+impl Walk for SyntaxTree {
+    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
+        for node in self.iter() {
+            node.walk(ctx)?;
+        }
+        Ok(())
+    }
+}
+
+impl Walk for SyntaxNode {
+    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
+        match self {
+            Self::Space => ctx.template.space(),
+            Self::Linebreak(_) => ctx.template.linebreak(),
+            Self::Parbreak(_) => ctx.template.parbreak(),
+            Self::Strong(_) => ctx.template.modify(|s| s.font_mut().strong ^= true),
+            Self::Emph(_) => ctx.template.modify(|s| s.font_mut().emph ^= true),
+            Self::Text(text) => ctx.template.text(text),
+            Self::Raw(raw) => raw.walk(ctx)?,
+            Self::Heading(heading) => heading.walk(ctx)?,
+            Self::List(list) => list.walk(ctx)?,
+            Self::Enum(enum_) => enum_.walk(ctx)?,
+            Self::Expr(expr) => match expr.eval(ctx)? {
+                Value::None => {}
+                Value::Int(v) => ctx.template.text(v.to_string()),
+                Value::Float(v) => ctx.template.text(v.to_string()),
+                Value::Str(v) => ctx.template.text(v),
+                Value::Template(v) => ctx.template += v,
+                // For values which can't be shown "naturally", we print the
+                // representation in monospace.
+                other => ctx.template.monospace(other.to_string()),
+            },
+        }
+        Ok(())
+    }
+}
+
+impl Walk for RawNode {
+    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
+        if self.block {
+            ctx.template.parbreak();
+        }
+
+        ctx.template.monospace(&self.text);
+
+        if self.block {
+            ctx.template.parbreak();
+        }
+
+        Ok(())
+    }
+}
+
+impl Walk for HeadingNode {
+    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
+        let level = self.level;
+        let body = self.body.eval(ctx)?;
+
+        ctx.template.parbreak();
+        ctx.template.save();
+        ctx.template.modify(move |state| {
+            let font = state.font_mut();
+            let upscale = 1.6 - 0.1 * level as f64;
+            font.size *= upscale;
+            font.strong = true;
+        });
+        ctx.template += body;
+        ctx.template.restore();
+        ctx.template.parbreak();
+
+        Ok(())
+    }
+}
+
+impl Walk for ListNode {
+    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
+        let body = self.body.eval(ctx)?;
+        walk_item(ctx, '•'.into(), body);
+        Ok(())
+    }
+}
+
+impl Walk for EnumNode {
+    fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
+        let body = self.body.eval(ctx)?;
+        let mut label = EcoString::new();
+        write!(&mut label, "{}.", self.number.unwrap_or(1)).unwrap();
+        walk_item(ctx, label, body);
+        Ok(())
+    }
+}
+
+fn walk_item(ctx: &mut EvalContext, label: EcoString, body: Template) {
+    ctx.template += Template::from_block(move |state| {
+        let label = ParNode {
+            dir: state.dirs.cross,
+            line_spacing: state.line_spacing(),
+            children: vec![ParChild::Text(
+                label.clone(),
+                state.aligns.cross,
+                Rc::clone(&state.font),
+            )],
+        };
+        StackNode {
+            dirs: Gen::new(state.dirs.main, state.dirs.cross),
+            children: vec![
+                StackChild::Any(label.into(), Gen::default()),
+                StackChild::Spacing((state.font.size / 2.0).into()),
+                StackChild::Any(body.to_stack(&state).into(), Gen::default()),
+            ],
+        }
+    });
+}
diff --git a/src/font.rs b/src/font.rs
index 978fb601a..dadf6830b 100644
--- a/src/font.rs
+++ b/src/font.rs
@@ -14,8 +14,7 @@ use crate::geom::Length;
 use crate::loading::{FileHash, Loader};
 
 /// A unique identifier for a loaded font face.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
-#[derive(Serialize, Deserialize)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Serialize, Deserialize)]
 pub struct FaceId(u32);
 
 impl FaceId {
@@ -271,7 +270,7 @@ impl Face {
 /// A length in em units.
 ///
 /// `1em` is the same as the font size.
-#[derive(Debug, Default, Copy, Clone, Eq, PartialEq, PartialOrd)]
+#[derive(Debug, Default, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
 pub struct Em(N64);
 
 impl Em {
@@ -343,11 +342,15 @@ impl Display for VerticalFontMetric {
 }
 
 /// A generic or named font family.
-#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub enum FontFamily {
+    /// A family that has "serifs", small strokes attached to letters.
     Serif,
+    /// A family in which glyphs do not have "serifs", small attached strokes.
     SansSerif,
+    /// A family in which (almost) all glyphs are of equal width.
     Monospace,
+    /// A specific family with a name.
     Named(String),
 }
 
@@ -575,15 +578,6 @@ impl Default for FontWeight {
     }
 }
 
-impl Display for FontWeight {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        match self.to_str() {
-            Some(name) => f.pad(name),
-            None => write!(f, "{}", self.0),
-        }
-    }
-}
-
 impl Debug for FontWeight {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         f.pad(match *self {
@@ -601,6 +595,15 @@ impl Debug for FontWeight {
     }
 }
 
+impl Display for FontWeight {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        match self.to_str() {
+            Some(name) => f.pad(name),
+            None => write!(f, "{}", self.0),
+        }
+    }
+}
+
 /// The width of a font face.
 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[derive(Serialize, Deserialize)]
@@ -707,15 +710,6 @@ impl Default for FontStretch {
     }
 }
 
-impl Display for FontStretch {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        match self.to_str() {
-            Some(name) => f.pad(name),
-            None => write!(f, "{}", self.to_ratio()),
-        }
-    }
-}
-
 impl Debug for FontStretch {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         f.pad(match *self {
@@ -733,6 +727,15 @@ impl Debug for FontStretch {
     }
 }
 
+impl Display for FontStretch {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        match self.to_str() {
+            Some(name) => f.pad(name),
+            None => write!(f, "{}", self.to_ratio()),
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/src/geom/angle.rs b/src/geom/angle.rs
index 8f18210c0..cf3e49a0f 100644
--- a/src/geom/angle.rs
+++ b/src/geom/angle.rs
@@ -1,8 +1,11 @@
-use super::*;
 use decorum::N64;
+use serde::{Deserialize, Serialize};
+
+use super::*;
 
 /// An angle.
 #[derive(Default, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[derive(Serialize, Deserialize)]
 pub struct Angle(N64);
 
 impl Angle {
@@ -52,6 +55,13 @@ impl Angle {
     }
 }
 
+impl Debug for Angle {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        let unit = AngularUnit::Deg;
+        write!(f, "{}{}", self.to_unit(unit), unit)
+    }
+}
+
 impl Display for Angle {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         // Format with the unit that yields the shortest output, preferring
@@ -66,13 +76,6 @@ impl Display for Angle {
     }
 }
 
-impl Debug for Angle {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        let unit = AngularUnit::Deg;
-        write!(f, "{}{}", self.to_unit(unit), unit)
-    }
-}
-
 impl Neg for Angle {
     type Output = Self;
 
@@ -134,7 +137,7 @@ impl Sum for Angle {
     }
 }
 /// Different units of angular measurement.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum AngularUnit {
     /// Radians.
     Rad,
diff --git a/src/geom/fr.rs b/src/geom/fr.rs
index 1768366a1..eaf539d96 100644
--- a/src/geom/fr.rs
+++ b/src/geom/fr.rs
@@ -33,18 +33,18 @@ impl Fractional {
     }
 }
 
-impl Display for Fractional {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{}fr", self.get())
-    }
-}
-
 impl Debug for Fractional {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         Display::fmt(self, f)
     }
 }
 
+impl Display for Fractional {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "{}fr", self.get())
+    }
+}
+
 impl Neg for Fractional {
     type Output = Self;
 
diff --git a/src/geom/length.rs b/src/geom/length.rs
index 343b523c3..3510fa6fa 100644
--- a/src/geom/length.rs
+++ b/src/geom/length.rs
@@ -126,6 +126,13 @@ impl Length {
     }
 }
 
+impl Debug for Length {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        let unit = LengthUnit::Pt;
+        write!(f, "{}{}", self.to_unit(unit), unit)
+    }
+}
+
 impl Display for Length {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         use LengthUnit::*;
@@ -142,13 +149,6 @@ impl Display for Length {
     }
 }
 
-impl Debug for Length {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        let unit = LengthUnit::Pt;
-        write!(f, "{}{}", self.to_unit(unit), unit)
-    }
-}
-
 impl Neg for Length {
     type Output = Self;
 
@@ -217,7 +217,7 @@ impl<'a> Sum<&'a Length> for Length {
 }
 
 /// Different units of length measurement.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum LengthUnit {
     /// Points.
     Pt,
diff --git a/src/geom/linear.rs b/src/geom/linear.rs
index 38d19b13c..6a20b8261 100644
--- a/src/geom/linear.rs
+++ b/src/geom/linear.rs
@@ -47,18 +47,18 @@ impl Linear {
     }
 }
 
-impl Display for Linear {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{} + {}", self.rel, self.abs)
-    }
-}
-
 impl Debug for Linear {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         write!(f, "{:?} + {:?}", self.rel, self.abs)
     }
 }
 
+impl Display for Linear {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "{} + {}", self.rel, self.abs)
+    }
+}
+
 impl From<Length> for Linear {
     fn from(abs: Length) -> Self {
         Self { rel: Relative::zero(), abs }
diff --git a/src/geom/relative.rs b/src/geom/relative.rs
index 149c0b9c9..7785788ce 100644
--- a/src/geom/relative.rs
+++ b/src/geom/relative.rs
@@ -46,18 +46,18 @@ impl Relative {
     }
 }
 
-impl Display for Relative {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{}%", 100.0 * self.get())
-    }
-}
-
 impl Debug for Relative {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         Display::fmt(self, f)
     }
 }
 
+impl Display for Relative {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "{}%", 100.0 * self.get())
+    }
+}
+
 impl Neg for Relative {
     type Output = Self;
 
diff --git a/src/geom/sides.rs b/src/geom/sides.rs
index f9fdc01f2..d4fdf2470 100644
--- a/src/geom/sides.rs
+++ b/src/geom/sides.rs
@@ -33,6 +33,14 @@ impl<T> Sides<T> {
     }
 }
 
+impl Sides<Length> {
+    /// A size with `left` and `right` summed into `width`, and `top` and
+    /// `bottom` summed into `height`.
+    pub fn size(self) -> Size {
+        Size::new(self.left + self.right, self.top + self.bottom)
+    }
+}
+
 impl Sides<Linear> {
     /// Resolve the linear sides relative to the given `size`.
     pub fn resolve(self, size: Size) -> Sides<Length> {
@@ -45,14 +53,6 @@ impl Sides<Linear> {
     }
 }
 
-impl Sides<Length> {
-    /// A size with `left` and `right` summed into `width`, and `top` and
-    /// `bottom` summed into `height`.
-    pub fn size(self) -> Size {
-        Size::new(self.left + self.right, self.top + self.bottom)
-    }
-}
-
 impl<T> Get<Side> for Sides<T> {
     type Component = T;
 
diff --git a/src/image.rs b/src/image.rs
index 6ccfb11d4..455f3105d 100644
--- a/src/image.rs
+++ b/src/image.rs
@@ -13,8 +13,7 @@ use serde::{Deserialize, Serialize};
 use crate::loading::{FileHash, Loader};
 
 /// A unique identifier for a loaded image.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
-#[derive(Serialize, Deserialize)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Serialize, Deserialize)]
 pub struct ImageId(u32);
 
 impl ImageId {
diff --git a/src/layout/background.rs b/src/layout/background.rs
index 793782fd8..306afd674 100644
--- a/src/layout/background.rs
+++ b/src/layout/background.rs
@@ -1,7 +1,6 @@
 use super::*;
 
 /// A node that places a rectangular filled background behind its child.
-#[derive(Debug, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub struct BackgroundNode {
     /// The kind of shape to use as a background.
diff --git a/src/layout/constraints.rs b/src/layout/constraints.rs
index 1a26daeb8..d808abd94 100644
--- a/src/layout/constraints.rs
+++ b/src/layout/constraints.rs
@@ -1,5 +1,3 @@
-use std::ops::Deref;
-
 use super::*;
 
 /// Carries an item that is only valid in certain regions and the constraints
@@ -12,14 +10,6 @@ pub struct Constrained<T> {
     pub constraints: Constraints,
 }
 
-impl<T> Deref for Constrained<T> {
-    type Target = T;
-
-    fn deref(&self) -> &Self::Target {
-        &self.item
-    }
-}
-
 /// Describe regions that match them.
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub struct Constraints {
diff --git a/src/layout/fixed.rs b/src/layout/fixed.rs
index 7f292f14e..02660d1d5 100644
--- a/src/layout/fixed.rs
+++ b/src/layout/fixed.rs
@@ -3,7 +3,6 @@ use decorum::N64;
 use super::*;
 
 /// A node that can fix its child's width and height.
-#[derive(Debug, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub struct FixedNode {
     /// The fixed width, if any.
@@ -78,7 +77,7 @@ impl Layout for FixedNode {
         // relayout with expansion.
         if let Some(aspect) = aspect {
             if width.is_none() && height.is_none() {
-                let needed = frames[0].size.cap(size);
+                let needed = frames[0].item.size.cap(size);
                 let width = needed.width.max(aspect * needed.height);
                 regions.current = Size::new(width, width / aspect);
                 regions.expand = Spec::splat(true);
diff --git a/src/layout/grid.rs b/src/layout/grid.rs
index d9b56b485..b4a1fe791 100644
--- a/src/layout/grid.rs
+++ b/src/layout/grid.rs
@@ -1,7 +1,6 @@
 use super::*;
 
 /// A node that arranges its children in a grid.
-#[derive(Debug, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub struct GridNode {
     /// The `main` and `cross` directions of this grid.
@@ -256,7 +255,7 @@ impl<'a> GridLayouter<'a> {
             for node in (0 .. self.rows.len()).filter_map(|y| self.cell(x, y)) {
                 let size = Gen::new(available, Length::inf()).to_size(self.main);
                 let regions = Regions::one(size, size, Spec::splat(false));
-                let frame = node.layout(ctx, &regions).remove(0);
+                let frame = node.layout(ctx, &regions).remove(0).item;
                 resolved.set_max(frame.size.get(self.cross));
             }
 
@@ -353,7 +352,7 @@ impl<'a> GridLayouter<'a> {
                 let mut sizes = node
                     .layout(ctx, &self.regions)
                     .into_iter()
-                    .map(|frame| frame.size.get(self.main));
+                    .map(|frame| frame.item.size.get(self.main));
 
                 if let Some(size) = sizes.next() {
                     first.set_max(size);
diff --git a/src/layout/image.rs b/src/layout/image.rs
index 02a907f5e..e3e5e7412 100644
--- a/src/layout/image.rs
+++ b/src/layout/image.rs
@@ -4,7 +4,6 @@ use crate::image::ImageId;
 use ::image::GenericImageView;
 
 /// An image node.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub struct ImageNode {
     /// The id of the image file.
diff --git a/src/layout/pad.rs b/src/layout/pad.rs
index 51025e3c1..3075472bf 100644
--- a/src/layout/pad.rs
+++ b/src/layout/pad.rs
@@ -1,7 +1,6 @@
 use super::*;
 
 /// A node that adds padding to its child.
-#[derive(Debug, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub struct PadNode {
     /// The amount of padding.
diff --git a/src/layout/par.rs b/src/layout/par.rs
index 317a91ade..84d784b02 100644
--- a/src/layout/par.rs
+++ b/src/layout/par.rs
@@ -1,4 +1,3 @@
-use std::fmt::{self, Debug, Formatter};
 use std::rc::Rc;
 
 use unicode_bidi::{BidiInfo, Level};
@@ -11,7 +10,6 @@ use crate::util::{EcoString, RangeExt, SliceExt};
 type Range = std::ops::Range<usize>;
 
 /// A node that arranges its children into a paragraph.
-#[derive(Debug, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub struct ParNode {
     /// The inline direction of this paragraph.
@@ -23,7 +21,6 @@ pub struct ParNode {
 }
 
 /// A child of a paragraph node.
-#[derive(Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub enum ParChild {
     /// Spacing between other nodes.
@@ -94,18 +91,6 @@ impl From<ParNode> for LayoutNode {
     }
 }
 
-impl Debug for ParChild {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        match self {
-            Self::Spacing(amount) => write!(f, "Spacing({:?})", amount),
-            Self::Text(text, align, _) => write!(f, "Text({:?}, {:?})", text, align),
-            Self::Any(any, align) => {
-                f.debug_tuple("Any").field(any).field(align).finish()
-            }
-        }
-    }
-}
-
 /// A paragraph representation in which children are already layouted and text
 /// is separated into shapable runs.
 struct ParLayouter<'a> {
diff --git a/src/layout/shaping.rs b/src/layout/shaping.rs
index ba8704ea7..fad7f2348 100644
--- a/src/layout/shaping.rs
+++ b/src/layout/shaping.rs
@@ -1,5 +1,4 @@
 use std::borrow::Cow;
-use std::fmt::{self, Debug, Formatter};
 use std::ops::Range;
 
 use rustybuzz::UnicodeBuffer;
@@ -11,12 +10,45 @@ use crate::geom::{Dir, Length, Point, Size};
 use crate::layout::Geometry;
 use crate::util::SliceExt;
 
+/// Shape text into [`ShapedText`].
+pub fn shape<'a>(
+    ctx: &mut LayoutContext,
+    text: &'a str,
+    dir: Dir,
+    state: &'a FontState,
+) -> ShapedText<'a> {
+    let mut glyphs = vec![];
+    if !text.is_empty() {
+        shape_segment(
+            ctx,
+            &mut glyphs,
+            0,
+            text,
+            dir,
+            state.size,
+            state.variant(),
+            state.families(),
+            None,
+        );
+    }
+
+    let (size, baseline) = measure(ctx, &glyphs, state);
+
+    ShapedText {
+        text,
+        dir,
+        state,
+        size,
+        baseline,
+        glyphs: Cow::Owned(glyphs),
+    }
+}
+
 /// The result of shaping text.
 ///
 /// This type contains owned or borrowed shaped text runs, which can be
 /// measured, used to reshape substrings more quickly and converted into a
 /// frame.
-#[derive(Clone)]
 pub struct ShapedText<'a> {
     /// The text that was shaped.
     pub text: &'a str,
@@ -33,7 +65,7 @@ pub struct ShapedText<'a> {
 }
 
 /// A single glyph resulting from shaping.
-#[derive(Debug, Copy, Clone)]
+#[derive(Copy, Clone)]
 pub struct ShapedGlyph {
     /// The font face the glyph is contained in.
     pub face_id: FaceId,
@@ -51,13 +83,6 @@ pub struct ShapedGlyph {
     pub safe_to_break: bool,
 }
 
-/// A visual side.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-enum Side {
-    Left,
-    Right,
-}
-
 impl<'a> ShapedText<'a> {
     /// Build the shaped text's frame.
     pub fn build(&self, ctx: &LayoutContext) -> Frame {
@@ -174,44 +199,10 @@ impl<'a> ShapedText<'a> {
     }
 }
 
-impl Debug for ShapedText<'_> {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "Shaped({:?})", self.text)
-    }
-}
-
-/// Shape text into [`ShapedText`].
-pub fn shape<'a>(
-    ctx: &mut LayoutContext,
-    text: &'a str,
-    dir: Dir,
-    state: &'a FontState,
-) -> ShapedText<'a> {
-    let mut glyphs = vec![];
-    if !text.is_empty() {
-        shape_segment(
-            ctx,
-            &mut glyphs,
-            0,
-            text,
-            dir,
-            state.size,
-            state.variant(),
-            state.families(),
-            None,
-        );
-    }
-
-    let (size, baseline) = measure(ctx, &glyphs, state);
-
-    ShapedText {
-        text,
-        dir,
-        state,
-        size,
-        baseline,
-        glyphs: Cow::Owned(glyphs),
-    }
+/// A visual side.
+enum Side {
+    Left,
+    Right,
 }
 
 /// Shape text with font fallback using the `families` iterator.
diff --git a/src/layout/stack.rs b/src/layout/stack.rs
index 51d17807d..d07f68d7c 100644
--- a/src/layout/stack.rs
+++ b/src/layout/stack.rs
@@ -1,7 +1,6 @@
 use super::*;
 
 /// A node that stacks its children.
-#[derive(Debug, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub struct StackNode {
     /// The `main` and `cross` directions of this stack.
@@ -14,7 +13,6 @@ pub struct StackNode {
 }
 
 /// A child of a stack node.
-#[derive(Debug, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "layout-cache", derive(Hash))]
 pub enum StackChild {
     /// Spacing between other nodes.
diff --git a/src/layout/tree.rs b/src/layout/tree.rs
index 1899a4d2d..05f94c381 100644
--- a/src/layout/tree.rs
+++ b/src/layout/tree.rs
@@ -1,7 +1,6 @@
 use super::*;
 
 use std::any::Any;
-use std::fmt::{self, Debug, Formatter};
 
 #[cfg(feature = "layout-cache")]
 use std::hash::{Hash, Hasher};
@@ -10,7 +9,6 @@ use std::hash::{Hash, Hasher};
 use fxhash::FxHasher64;
 
 /// A tree of layout nodes.
-#[derive(Debug, Clone, Eq, PartialEq)]
 pub struct LayoutTree {
     /// Runs of pages with the same properties.
     pub runs: Vec<PageRun>,
@@ -24,7 +22,6 @@ impl LayoutTree {
 }
 
 /// A run of pages that all have the same properties.
-#[derive(Debug, Clone, Eq, PartialEq)]
 pub struct PageRun {
     /// The size of each page.
     pub size: Size,
@@ -47,7 +44,7 @@ impl PageRun {
 
 /// A dynamic layouting node.
 pub struct LayoutNode {
-    node: Box<dyn Bounds>,
+    node: Box<dyn Layout>,
     #[cfg(feature = "layout-cache")]
     hash: u64,
 }
@@ -57,7 +54,7 @@ impl LayoutNode {
     #[cfg(not(feature = "layout-cache"))]
     pub fn new<T>(node: T) -> Self
     where
-        T: Layout + Debug + Clone + Eq + PartialEq + 'static,
+        T: Layout + 'static,
     {
         Self { node: Box::new(node) }
     }
@@ -66,7 +63,7 @@ impl LayoutNode {
     #[cfg(feature = "layout-cache")]
     pub fn new<T>(node: T) -> Self
     where
-        T: Layout + Debug + Clone + Eq + PartialEq + Hash + 'static,
+        T: Layout + Hash + 'static,
     {
         let hash = {
             let mut state = FxHasher64::default();
@@ -99,60 +96,9 @@ impl Layout for LayoutNode {
     }
 }
 
-impl Debug for LayoutNode {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        self.node.fmt(f)
-    }
-}
-
-impl Clone for LayoutNode {
-    fn clone(&self) -> Self {
-        Self {
-            node: self.node.dyn_clone(),
-            #[cfg(feature = "layout-cache")]
-            hash: self.hash,
-        }
-    }
-}
-
-impl Eq for LayoutNode {}
-
-impl PartialEq for LayoutNode {
-    fn eq(&self, other: &Self) -> bool {
-        self.node.dyn_eq(other.node.as_ref())
-    }
-}
-
 #[cfg(feature = "layout-cache")]
 impl Hash for LayoutNode {
     fn hash<H: Hasher>(&self, state: &mut H) {
         state.write_u64(self.hash);
     }
 }
-
-trait Bounds: Layout + Debug + 'static {
-    fn as_any(&self) -> &dyn Any;
-    fn dyn_eq(&self, other: &dyn Bounds) -> bool;
-    fn dyn_clone(&self) -> Box<dyn Bounds>;
-}
-
-impl<T> Bounds for T
-where
-    T: Layout + Debug + Eq + PartialEq + Clone + 'static,
-{
-    fn as_any(&self) -> &dyn Any {
-        self
-    }
-
-    fn dyn_eq(&self, other: &dyn Bounds) -> bool {
-        if let Some(other) = other.as_any().downcast_ref::<Self>() {
-            self == other
-        } else {
-            false
-        }
-    }
-
-    fn dyn_clone(&self) -> Box<dyn Bounds> {
-        Box::new(self.clone())
-    }
-}
diff --git a/src/loading/fs.rs b/src/loading/fs.rs
index 46e3dba17..d03df3bab 100644
--- a/src/loading/fs.rs
+++ b/src/loading/fs.rs
@@ -13,7 +13,7 @@ use crate::font::FaceInfo;
 /// Loads fonts and files from the local file system.
 ///
 /// _This is only available when the `fs` feature is enabled._
-#[derive(Debug, Default, Clone)]
+#[derive(Default)]
 pub struct FsLoader {
     faces: Vec<FaceInfo>,
 }
diff --git a/src/loading/mem.rs b/src/loading/mem.rs
index d7fb178f1..9ff02d2d7 100644
--- a/src/loading/mem.rs
+++ b/src/loading/mem.rs
@@ -9,7 +9,7 @@ use crate::font::FaceInfo;
 use crate::util::PathExt;
 
 /// Loads fonts and files from an in-memory storage.
-#[derive(Debug, Default, Clone)]
+#[derive(Default)]
 pub struct MemLoader {
     faces: Vec<FaceInfo>,
     files: HashMap<PathBuf, Cow<'static, [u8]>>,
diff --git a/src/loading/mod.rs b/src/loading/mod.rs
index e6cca0127..4841e7522 100644
--- a/src/loading/mod.rs
+++ b/src/loading/mod.rs
@@ -11,15 +11,12 @@ pub use mem::*;
 use std::io;
 use std::path::Path;
 
-use serde::{Deserialize, Serialize};
-
 use crate::font::FaceInfo;
 
 /// A hash that identifies a file.
 ///
 /// Such a hash can be [resolved](Loader::resolve) from a path.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
-#[derive(Serialize, Deserialize)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub struct FileHash(pub u64);
 
 /// Loads resources from a local or remote source.
diff --git a/src/paper.rs b/src/paper.rs
index 1a3391a1b..5c9775b86 100644
--- a/src/paper.rs
+++ b/src/paper.rs
@@ -3,7 +3,7 @@
 use crate::geom::{Length, Linear, Relative, Sides, Size};
 
 /// Specification of a paper.
-#[derive(Debug, Copy, Clone, PartialEq)]
+#[derive(Debug, Copy, Clone)]
 pub struct Paper {
     /// The broad class this paper belongs to.
     class: PaperClass,
diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index 37b65c048..649b4eb80 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -201,7 +201,7 @@ fn list_item(p: &mut Parser) -> SyntaxNode {
     let column = p.column(start);
     p.eat_assert(Token::Hyph);
     let body = tree_indented(p, column);
-    SyntaxNode::List(Box::new(ListItem { span: p.span_from(start), body }))
+    SyntaxNode::List(Box::new(ListNode { span: p.span_from(start), body }))
 }
 
 /// Parse a single enum item.
@@ -210,7 +210,7 @@ fn enum_item(p: &mut Parser, number: Option<usize>) -> SyntaxNode {
     let column = p.column(start);
     p.eat_assert(Token::Numbering(number));
     let body = tree_indented(p, column);
-    SyntaxNode::Enum(Box::new(EnumItem {
+    SyntaxNode::Enum(Box::new(EnumNode {
         span: p.span_from(start),
         number,
         body,
diff --git a/src/parse/parser.rs b/src/parse/parser.rs
index 83e77a6a2..c035319de 100644
--- a/src/parse/parser.rs
+++ b/src/parse/parser.rs
@@ -1,4 +1,3 @@
-use std::fmt::{self, Debug, Formatter};
 use std::ops::Range;
 
 use super::{TokenMode, Tokens};
@@ -28,7 +27,6 @@ pub struct Parser<'s> {
 }
 
 /// A logical group of tokens, e.g. `[...]`.
-#[derive(Debug, Copy, Clone)]
 struct GroupEntry {
     /// The start index of the group. Used by `Parser::end_group` to return the
     /// group's full span.
@@ -391,11 +389,3 @@ impl<'s> Parser<'s> {
         self.groups.iter().any(|g| g.kind == kind)
     }
 }
-
-impl Debug for Parser<'_> {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        let mut s = self.tokens.scanner();
-        s.jump(self.next_start());
-        write!(f, "Parser({}|{})", s.eaten(), s.rest())
-    }
-}
diff --git a/src/parse/scanner.rs b/src/parse/scanner.rs
index f893c4d3e..8e3e42782 100644
--- a/src/parse/scanner.rs
+++ b/src/parse/scanner.rs
@@ -1,4 +1,3 @@
-use std::fmt::{self, Debug, Formatter};
 use std::slice::SliceIndex;
 
 /// A featureful char-based scanner.
@@ -153,12 +152,6 @@ impl<'s> Scanner<'s> {
     }
 }
 
-impl Debug for Scanner<'_> {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "Scanner({}|{})", self.eaten(), self.rest())
-    }
-}
-
 /// Whether this character denotes a newline.
 #[inline]
 pub fn is_newline(character: char) -> bool {
diff --git a/src/parse/tokens.rs b/src/parse/tokens.rs
index 684e340e2..91d3ab7f5 100644
--- a/src/parse/tokens.rs
+++ b/src/parse/tokens.rs
@@ -1,11 +1,8 @@
-use std::fmt::{self, Debug, Formatter};
-
 use super::{is_newline, Scanner};
 use crate::geom::{AngularUnit, LengthUnit};
 use crate::syntax::*;
 
 /// An iterator over the tokens of a string of source code.
-#[derive(Clone)]
 pub struct Tokens<'s> {
     s: Scanner<'s>,
     mode: TokenMode,
@@ -481,12 +478,6 @@ impl<'s> Tokens<'s> {
     }
 }
 
-impl Debug for Tokens<'_> {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "Tokens({}|{})", self.s.eaten(), self.s.rest())
-    }
-}
-
 fn keyword(ident: &str) -> Option<Token<'static>> {
     Some(match ident {
         "not" => Token::Not,
@@ -512,6 +503,8 @@ fn keyword(ident: &str) -> Option<Token<'static>> {
 #[cfg(test)]
 #[allow(non_snake_case)]
 mod tests {
+    use std::fmt::Debug;
+
     use super::*;
 
     use Option::None;
diff --git a/src/source.rs b/src/source.rs
index 877fd7294..b02af1b60 100644
--- a/src/source.rs
+++ b/src/source.rs
@@ -15,8 +15,7 @@ use crate::parse::{is_newline, Scanner};
 use crate::util::PathExt;
 
 /// A unique identifier for a loaded source file.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
-#[derive(Serialize, Deserialize)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Serialize, Deserialize)]
 pub struct SourceId(u32);
 
 impl SourceId {
@@ -252,12 +251,6 @@ impl SourceFile {
     }
 }
 
-impl AsRef<str> for SourceFile {
-    fn as_ref(&self) -> &str {
-        &self.src
-    }
-}
-
 /// The indices at which lines start (right behind newlines).
 ///
 /// The beginning of the string (index 0) is not returned.
@@ -276,6 +269,12 @@ fn newlines(string: &str) -> impl Iterator<Item = usize> + '_ {
     })
 }
 
+impl AsRef<str> for SourceFile {
+    fn as_ref(&self) -> &str {
+        &self.src
+    }
+}
+
 #[cfg(feature = "codespan-reporting")]
 impl<'a> Files<'a> for SourceStore {
     type FileId = SourceId;
diff --git a/src/syntax/ident.rs b/src/syntax/ident.rs
index 66ffb46d8..c47e6fb1c 100644
--- a/src/syntax/ident.rs
+++ b/src/syntax/ident.rs
@@ -12,7 +12,7 @@ use crate::util::EcoString;
 /// - `_` and `-` as continuing characters.
 ///
 /// [uax31]: http://www.unicode.org/reports/tr31/
-#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct Ident {
     /// The source code location.
     pub span: Span,
diff --git a/src/syntax/node.rs b/src/syntax/node.rs
index 4ff69c17d..875d32f5a 100644
--- a/src/syntax/node.rs
+++ b/src/syntax/node.rs
@@ -20,9 +20,9 @@ pub enum SyntaxNode {
     /// A section heading: `= Introduction`.
     Heading(Box<HeadingNode>),
     /// An item in an unordered list: `- ...`.
-    List(Box<ListItem>),
+    List(Box<ListNode>),
     /// An item in an enumeration (ordered list): `1. ...`.
-    Enum(Box<EnumItem>),
+    Enum(Box<EnumNode>),
     /// An expression.
     Expr(Expr),
 }
@@ -55,7 +55,7 @@ pub struct HeadingNode {
 
 /// An item in an unordered list: `- ...`.
 #[derive(Debug, Clone, PartialEq)]
-pub struct ListItem {
+pub struct ListNode {
     /// The source code location.
     pub span: Span,
     /// The contents of the list item.
@@ -64,7 +64,7 @@ pub struct ListItem {
 
 /// An item in an enumeration (ordered list): `1. ...`.
 #[derive(Debug, Clone, PartialEq)]
-pub struct EnumItem {
+pub struct EnumNode {
     /// The source code location.
     pub span: Span,
     /// The number, if any.
diff --git a/src/syntax/pretty.rs b/src/syntax/pretty.rs
index cf9ee69de..3c59914fd 100644
--- a/src/syntax/pretty.rs
+++ b/src/syntax/pretty.rs
@@ -94,14 +94,14 @@ impl Pretty for SyntaxNode {
             Self::Emph(_) => p.push('_'),
             Self::Text(text) => p.push_str(text),
             Self::Raw(raw) => raw.pretty(p),
-            Self::Heading(n) => n.pretty(p),
-            Self::List(n) => n.pretty(p),
-            Self::Enum(n) => n.pretty(p),
-            Self::Expr(n) => {
-                if n.has_short_form() {
+            Self::Heading(heading) => heading.pretty(p),
+            Self::List(list) => list.pretty(p),
+            Self::Enum(enum_) => enum_.pretty(p),
+            Self::Expr(expr) => {
+                if expr.has_short_form() {
                     p.push('#');
                 }
-                n.pretty(p);
+                expr.pretty(p);
             }
         }
     }
@@ -173,14 +173,14 @@ impl Pretty for HeadingNode {
     }
 }
 
-impl Pretty for ListItem {
+impl Pretty for ListNode {
     fn pretty(&self, p: &mut Printer) {
         p.push_str("- ");
         self.body.pretty(p);
     }
 }
 
-impl Pretty for EnumItem {
+impl Pretty for EnumNode {
     fn pretty(&self, p: &mut Printer) {
         if let Some(number) = self.number {
             write!(p, "{}", number).unwrap();
diff --git a/src/syntax/span.rs b/src/syntax/span.rs
index e4a4fd328..bfb9e755c 100644
--- a/src/syntax/span.rs
+++ b/src/syntax/span.rs
@@ -1,3 +1,4 @@
+use std::cmp::Ordering;
 use std::fmt::{self, Debug, Formatter};
 use std::ops::{Add, Range};
 
@@ -6,8 +7,7 @@ use serde::{Deserialize, Serialize};
 use crate::source::SourceId;
 
 /// A value with the span it corresponds to in the source code.
-#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
-#[derive(Serialize, Deserialize)]
+#[derive(Copy, Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct Spanned<T> {
     /// The spanned value.
     pub v: T,
@@ -48,8 +48,7 @@ impl<T: Debug> Debug for Spanned<T> {
 }
 
 /// Bounds of a slice of source code.
-#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
-#[derive(Serialize, Deserialize)]
+#[derive(Copy, Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct Span {
     /// The id of the source file.
     pub source: SourceId,
@@ -127,9 +126,18 @@ impl Debug for Span {
     }
 }
 
+impl PartialOrd for Span {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        if self.source == other.source {
+            Some(self.start.cmp(&other.start).then(self.end.cmp(&other.end)))
+        } else {
+            None
+        }
+    }
+}
+
 /// A byte position in source code.
-#[derive(Default, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
-#[derive(Serialize, Deserialize)]
+#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Serialize, Deserialize)]
 pub struct Pos(pub u32);
 
 impl Pos {
@@ -148,17 +156,6 @@ impl Debug for Pos {
     }
 }
 
-impl<T> Add<T> for Pos
-where
-    T: Into<Pos>,
-{
-    type Output = Self;
-
-    fn add(self, rhs: T) -> Self {
-        Pos(self.0 + rhs.into().0)
-    }
-}
-
 impl From<u32> for Pos {
     fn from(index: u32) -> Self {
         Self(index)
@@ -171,6 +168,17 @@ impl From<usize> for Pos {
     }
 }
 
+impl<T> Add<T> for Pos
+where
+    T: Into<Pos>,
+{
+    type Output = Self;
+
+    fn add(self, rhs: T) -> Self {
+        Pos(self.0 + rhs.into().0)
+    }
+}
+
 /// Convert a position or range into a span.
 pub trait IntoSpan {
     /// Convert into a span by providing the source id.
diff --git a/src/syntax/token.rs b/src/syntax/token.rs
index a4d1867a8..219395cf9 100644
--- a/src/syntax/token.rs
+++ b/src/syntax/token.rs
@@ -157,7 +157,7 @@ pub enum Token<'s> {
 }
 
 /// A quoted string token: `"..."`.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq)]
 pub struct StrToken<'s> {
     /// The string inside the quotes.
     ///
@@ -170,7 +170,7 @@ pub struct StrToken<'s> {
 }
 
 /// A raw block token: `` `...` ``.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq)]
 pub struct RawToken<'s> {
     /// The raw text between the backticks.
     pub text: &'s str,
@@ -181,7 +181,7 @@ pub struct RawToken<'s> {
 }
 
 /// A math formula token: `$2pi + x$` or `$[f'(x) = x^2]$`.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq)]
 pub struct MathToken<'s> {
     /// The formula between the dollars.
     pub formula: &'s str,
@@ -193,7 +193,7 @@ pub struct MathToken<'s> {
 }
 
 /// A unicode escape sequence token: `\u{1F5FA}`.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq)]
 pub struct UnicodeEscapeToken<'s> {
     /// The escape sequence between the braces.
     pub sequence: &'s str,
diff --git a/src/syntax/visit.rs b/src/syntax/visit.rs
index 2b4649dea..fe270ac5a 100644
--- a/src/syntax/visit.rs
+++ b/src/syntax/visit.rs
@@ -104,12 +104,12 @@ impl_visitors! {
         v.visit_tree(r!(heading.body));
     }
 
-    visit_list(v, item: ListItem) {
-        v.visit_tree(r!(item.body));
+    visit_list(v, list: ListNode) {
+        v.visit_tree(r!(list.body));
     }
 
-    visit_enum(v, item: EnumItem) {
-        v.visit_tree(r!(item.body));
+    visit_enum(v, enum_: EnumNode) {
+        v.visit_tree(r!(enum_.body));
     }
 
     visit_expr(v, expr: Expr) {
diff --git a/src/util/eco.rs b/src/util/eco.rs
index b44214bdf..f1dfdfaf9 100644
--- a/src/util/eco.rs
+++ b/src/util/eco.rs
@@ -163,24 +163,6 @@ impl EcoString {
     }
 }
 
-impl Default for EcoString {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl Display for EcoString {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        Display::fmt(self.as_str(), f)
-    }
-}
-
-impl Debug for EcoString {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        Debug::fmt(self.as_str(), f)
-    }
-}
-
 impl Deref for EcoString {
     type Target = str;
 
@@ -201,6 +183,24 @@ impl Deref for EcoString {
     }
 }
 
+impl Default for EcoString {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Debug for EcoString {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        Debug::fmt(self.as_str(), f)
+    }
+}
+
+impl Display for EcoString {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        Display::fmt(self.as_str(), f)
+    }
+}
+
 impl Eq for EcoString {}
 
 impl PartialEq for EcoString {
diff --git a/tests/typeset.rs b/tests/typeset.rs
index 7aacf9e0e..a14bafaf4 100644
--- a/tests/typeset.rs
+++ b/tests/typeset.rs
@@ -248,8 +248,9 @@ fn test_part(
         error.trace.clear();
     }
 
-    ref_errors.sort();
-    errors.sort();
+    // The comparison never fails since all spans are from the same source file.
+    ref_errors.sort_by(|a, b| a.span.partial_cmp(&b.span).unwrap());
+    errors.sort_by(|a, b| a.span.partial_cmp(&b.span).unwrap());
 
     if errors != ref_errors {
         println!("  Subtest {} does not match expected errors. ❌", i);