Make clippy happier and remove `Str`

34 files changed, 340 insertions, 427 deletions

diff --git a/src/eval/array.rs b/src/eval/array.rs
index f6adee6d..912aa3c0 100644
--- a/src/eval/array.rs
+++ b/src/eval/array.rs
@@ -70,7 +70,7 @@ impl Array {
 
     /// Clear the array.
     pub fn clear(&mut self) {
-        if Rc::strong_count(&mut self.0) == 1 {
+        if Rc::strong_count(&self.0) == 1 {
             Rc::make_mut(&mut self.0).clear();
         } else {
             *self = Self::new();
diff --git a/src/eval/dict.rs b/src/eval/dict.rs
index e7a46b40..0d7198e1 100644
--- a/src/eval/dict.rs
+++ b/src/eval/dict.rs
@@ -4,9 +4,9 @@ use std::iter::FromIterator;
 use std::ops::{Add, AddAssign};
 use std::rc::Rc;
 
-use super::{Str, Value};
+use super::Value;
 use crate::diag::StrResult;
-use crate::util::RcExt;
+use crate::util::{EcoString, RcExt};
 
 /// Create a new [`Dict`] from key-value pairs.
 #[allow(unused_macros)]
@@ -21,7 +21,7 @@ macro_rules! dict {
 
 /// A dictionary from strings to values with clone-on-write value semantics.
 #[derive(Default, Clone, PartialEq)]
-pub struct Dict(Rc<BTreeMap<Str, Value>>);
+pub struct Dict(Rc<BTreeMap<EcoString, Value>>);
 
 impl Dict {
     /// Create a new, empty dictionary.
@@ -30,7 +30,7 @@ impl Dict {
     }
 
     /// Create a new dictionary from a mapping of strings to values.
-    pub fn from_map(map: BTreeMap<Str, Value>) -> Self {
+    pub fn from_map(map: BTreeMap<EcoString, Value>) -> Self {
         Self(Rc::new(map))
     }
 
@@ -45,7 +45,7 @@ impl Dict {
     }
 
     /// Borrow the value the given `key` maps to.
-    pub fn get(&self, key: Str) -> StrResult<&Value> {
+    pub fn get(&self, key: EcoString) -> StrResult<&Value> {
         self.0.get(&key).ok_or_else(|| missing_key(&key))
     }
 
@@ -53,18 +53,18 @@ impl Dict {
     ///
     /// This inserts the key with [`None`](Value::None) as the value if not
     /// present so far.
-    pub fn get_mut(&mut self, key: Str) -> &mut Value {
-        Rc::make_mut(&mut self.0).entry(key.into()).or_default()
+    pub fn get_mut(&mut self, key: EcoString) -> &mut Value {
+        Rc::make_mut(&mut self.0).entry(key).or_default()
     }
 
     /// Insert a mapping from the given `key` to the given `value`.
-    pub fn insert(&mut self, key: Str, value: Value) {
-        Rc::make_mut(&mut self.0).insert(key.into(), value);
+    pub fn insert(&mut self, key: EcoString, value: Value) {
+        Rc::make_mut(&mut self.0).insert(key, value);
     }
 
     /// Clear the dictionary.
     pub fn clear(&mut self) {
-        if Rc::strong_count(&mut self.0) == 1 {
+        if Rc::strong_count(&self.0) == 1 {
             Rc::make_mut(&mut self.0).clear();
         } else {
             *self = Self::new();
@@ -72,14 +72,14 @@ impl Dict {
     }
 
     /// Iterate over pairs of references to the contained keys and values.
-    pub fn iter(&self) -> std::collections::btree_map::Iter<Str, Value> {
+    pub fn iter(&self) -> std::collections::btree_map::Iter<EcoString, Value> {
         self.0.iter()
     }
 }
 
 /// The missing key access error message.
 #[cold]
-fn missing_key(key: &Str) -> String {
+fn missing_key(key: &EcoString) -> String {
     format!("dictionary does not contain key: {:?}", key)
 }
 
@@ -119,21 +119,21 @@ impl AddAssign for Dict {
     }
 }
 
-impl Extend<(Str, Value)> for Dict {
-    fn extend<T: IntoIterator<Item = (Str, Value)>>(&mut self, iter: T) {
+impl Extend<(EcoString, Value)> for Dict {
+    fn extend<T: IntoIterator<Item = (EcoString, 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 {
+impl FromIterator<(EcoString, Value)> for Dict {
+    fn from_iter<T: IntoIterator<Item = (EcoString, 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>;
+    type Item = (EcoString, Value);
+    type IntoIter = std::collections::btree_map::IntoIter<EcoString, Value>;
 
     fn into_iter(self) -> Self::IntoIter {
         Rc::take(self.0).into_iter()
@@ -141,8 +141,8 @@ impl IntoIterator for Dict {
 }
 
 impl<'a> IntoIterator for &'a Dict {
-    type Item = (&'a Str, &'a Value);
-    type IntoIter = std::collections::btree_map::Iter<'a, Str, Value>;
+    type Item = (&'a EcoString, &'a Value);
+    type IntoIter = std::collections::btree_map::Iter<'a, EcoString, Value>;
 
     fn into_iter(self) -> Self::IntoIter {
         self.iter()
diff --git a/src/eval/function.rs b/src/eval/function.rs
index cbbc0b36..c83d8b2b 100644
--- a/src/eval/function.rs
+++ b/src/eval/function.rs
@@ -1,7 +1,7 @@
 use std::fmt::{self, Debug, Formatter, Write};
 use std::rc::Rc;
 
-use super::{Cast, EvalContext, Str, Value};
+use super::{Cast, EvalContext, Value};
 use crate::diag::{At, TypResult};
 use crate::syntax::{Span, Spanned};
 use crate::util::EcoString;
@@ -52,7 +52,10 @@ impl Debug for Function {
 impl PartialEq for Function {
     fn eq(&self, other: &Self) -> bool {
         // We cast to thin pointers for comparison.
-        Rc::as_ptr(&self.0) as *const () == Rc::as_ptr(&other.0) as *const ()
+        std::ptr::eq(
+            Rc::as_ptr(&self.0) as *const (),
+            Rc::as_ptr(&other.0) as *const (),
+        )
     }
 }
 
@@ -71,7 +74,7 @@ pub struct Arg {
     /// The span of the whole argument.
     pub span: Span,
     /// The name of the argument (`None` for positional arguments).
-    pub name: Option<Str>,
+    pub name: Option<EcoString>,
     /// The value of the argument.
     pub value: Spanned<Value>,
 }
@@ -173,7 +176,7 @@ impl Args {
     }
 
     /// Reinterpret these arguments as actually being a dictionary key.
-    pub fn into_key(self) -> TypResult<Str> {
+    pub fn into_key(self) -> TypResult<EcoString> {
         self.into_castable("key")
     }
 
diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index fda2184e..1ff497e8 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -5,8 +5,6 @@ mod array;
 #[macro_use]
 mod dict;
 #[macro_use]
-mod str;
-#[macro_use]
 mod value;
 mod capture;
 mod function;
@@ -15,7 +13,6 @@ mod scope;
 mod template;
 mod walk;
 
-pub use self::str::*;
 pub use array::*;
 pub use capture::*;
 pub use dict::*;
@@ -31,6 +28,8 @@ use std::io;
 use std::mem;
 use std::path::PathBuf;
 
+use unicode_segmentation::UnicodeSegmentation;
+
 use crate::diag::{At, Error, StrResult, Trace, Tracepoint, TypResult};
 use crate::geom::{Angle, Fractional, Length, Relative};
 use crate::image::ImageStore;
@@ -38,7 +37,7 @@ use crate::loading::Loader;
 use crate::source::{SourceId, SourceStore};
 use crate::syntax::ast::*;
 use crate::syntax::{Span, Spanned};
-use crate::util::RefMutExt;
+use crate::util::{EcoString, RefMutExt};
 use crate::Context;
 
 /// Evaluate a parsed source file into a module.
@@ -210,7 +209,7 @@ impl Eval for Lit {
             LitKind::Angle(v, unit) => Value::Angle(Angle::with_unit(v, unit)),
             LitKind::Percent(v) => Value::Relative(Relative::new(v / 100.0)),
             LitKind::Fractional(v) => Value::Fractional(Fractional::new(v)),
-            LitKind::Str(ref v) => Value::Str(v.into()),
+            LitKind::Str(ref v) => Value::Str(v.clone()),
         })
     }
 }
@@ -239,7 +238,7 @@ impl Eval for DictExpr {
 
     fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
         self.items()
-            .map(|x| Ok((x.name().take().into(), x.expr().eval(ctx)?)))
+            .map(|x| Ok((x.name().take(), x.expr().eval(ctx)?)))
             .collect()
     }
 }
@@ -401,7 +400,7 @@ impl Eval for CallArgs {
                 CallArg::Named(named) => {
                     items.push(Arg {
                         span,
-                        name: Some(named.name().take().into()),
+                        name: Some(named.name().take()),
                         value: Spanned::new(named.expr().eval(ctx)?, named.expr().span()),
                     });
                 }
@@ -600,7 +599,7 @@ impl Eval for ForExpr {
 
         match (key, value, iter) {
             (None, v, Value::Str(string)) => {
-                iter!(for (v => value) in string.iter());
+                iter!(for (v => value) in string.graphemes(true));
             }
             (None, v, Value::Array(array)) => {
                 iter!(for (v => value) in array.into_iter());
@@ -629,7 +628,7 @@ impl Eval for ImportExpr {
 
     fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
         let path = self.path();
-        let resolved = path.eval(ctx)?.cast::<Str>().at(path.span())?;
+        let resolved = path.eval(ctx)?.cast::<EcoString>().at(path.span())?;
         let file = ctx.import(&resolved, path.span())?;
         let module = &ctx.modules[&file];
 
@@ -659,7 +658,7 @@ impl Eval for IncludeExpr {
 
     fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
         let path = self.path();
-        let resolved = path.eval(ctx)?.cast::<Str>().at(path.span())?;
+        let resolved = path.eval(ctx)?.cast::<EcoString>().at(path.span())?;
         let file = ctx.import(&resolved, path.span())?;
         let module = &ctx.modules[&file];
         Ok(Value::Template(module.template.clone()))
diff --git a/src/eval/ops.rs b/src/eval/ops.rs
index 732bfb14..e40fa78d 100644
--- a/src/eval/ops.rs
+++ b/src/eval/ops.rs
@@ -1,7 +1,9 @@
 use std::cmp::Ordering;
+use std::convert::TryFrom;
 
 use super::Value;
 use crate::diag::StrResult;
+use crate::util::EcoString;
 use Value::*;
 
 /// Bail with a type mismatch error.
@@ -150,8 +152,8 @@ pub fn mul(lhs: Value, rhs: Value) -> StrResult<Value> {
         (Fractional(a), Float(b)) => Fractional(a * b),
         (Int(a), Fractional(b)) => Fractional(a as f64 * b),
 
-        (Str(a), Int(b)) => Str(a.repeat(b)?),
-        (Int(a), Str(b)) => Str(b.repeat(a)?),
+        (Str(a), Int(b)) => Str(repeat_str(a, b)?),
+        (Int(a), Str(b)) => Str(repeat_str(b, a)?),
         (Array(a), Int(b)) => Array(a.repeat(b)?),
         (Int(a), Array(b)) => Array(b.repeat(a)?),
         (Template(a), Int(b)) => Template(a.repeat(b)?),
@@ -161,6 +163,16 @@ pub fn mul(lhs: Value, rhs: Value) -> StrResult<Value> {
     })
 }
 
+/// Repeat a string a number of times.
+fn repeat_str(string: EcoString, n: i64) -> StrResult<EcoString> {
+    let n = usize::try_from(n)
+        .ok()
+        .and_then(|n| string.len().checked_mul(n).map(|_| n))
+        .ok_or_else(|| format!("cannot repeat this string {} times", n))?;
+
+    Ok(string.repeat(n))
+}
+
 /// Compute the quotient of two values.
 pub fn div(lhs: Value, rhs: Value) -> StrResult<Value> {
     Ok(match (lhs, rhs) {
diff --git a/src/eval/str.rs b/src/eval/str.rs
deleted file mode 100644
index 800d1709..00000000
--- a/src/eval/str.rs
+++ /dev/null
@@ -1,164 +0,0 @@
-use std::borrow::Borrow;
-use std::convert::TryFrom;
-use std::fmt::{self, Debug, Formatter, Write};
-use std::ops::{Add, AddAssign, Deref};
-
-use unicode_segmentation::UnicodeSegmentation;
-
-use crate::diag::StrResult;
-use crate::util::EcoString;
-
-/// Create a new [`Str`] from a format string.
-macro_rules! format_str {
-    ($($tts:tt)*) => {{
-        use std::fmt::Write;
-        let mut s = $crate::eval::Str::new();
-        write!(s, $($tts)*).unwrap();
-        s
-    }};
-}
-
-/// A string value with inline storage and clone-on-write semantics.
-#[derive(Default, Clone, Eq, PartialEq, Ord, PartialOrd)]
-pub struct Str(EcoString);
-
-impl Str {
-    /// Create a new, empty string.
-    pub fn new() -> Self {
-        Self::default()
-    }
-
-    /// Whether the string is empty.
-    pub fn is_empty(&self) -> bool {
-        self.0.is_empty()
-    }
-
-    /// The length of the string in bytes.
-    pub fn len(&self) -> i64 {
-        self.0.len() as i64
-    }
-
-    /// Borrow this as a string slice.
-    pub fn as_str(&self) -> &str {
-        self.0.as_str()
-    }
-
-    /// Return an iterator over the grapheme clusters as strings.
-    pub fn iter(&self) -> impl Iterator<Item = Str> + '_ {
-        self.graphemes(true).map(Into::into)
-    }
-
-    /// Repeat this string `n` times.
-    pub fn repeat(&self, n: i64) -> StrResult<Self> {
-        let n = usize::try_from(n)
-            .ok()
-            .and_then(|n| self.0.len().checked_mul(n).map(|_| n))
-            .ok_or_else(|| format!("cannot repeat this string {} times", n))?;
-
-        Ok(self.0.repeat(n).into())
-    }
-}
-
-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 {
-        f.write_char('"')?;
-        for c in self.chars() {
-            match c {
-                '\\' => f.write_str(r"\\")?,
-                '"' => f.write_str(r#"\""#)?,
-                '\n' => f.write_str(r"\n")?,
-                '\r' => f.write_str(r"\r")?,
-                '\t' => f.write_str(r"\t")?,
-                _ => f.write_char(c)?,
-            }
-        }
-        f.write_char('"')
-    }
-}
-
-impl Add for Str {
-    type Output = Self;
-
-    fn add(mut self, rhs: Self) -> Self::Output {
-        self += rhs;
-        self
-    }
-}
-
-impl AddAssign for Str {
-    fn add_assign(&mut self, rhs: Self) {
-        self.0.push_str(rhs.as_str());
-    }
-}
-
-impl Write for Str {
-    fn write_str(&mut self, s: &str) -> fmt::Result {
-        self.0.write_str(s)
-    }
-
-    fn write_char(&mut self, c: char) -> fmt::Result {
-        self.0.write_char(c)
-    }
-}
-
-impl AsRef<str> for Str {
-    fn as_ref(&self) -> &str {
-        self
-    }
-}
-
-impl Borrow<str> for Str {
-    fn borrow(&self) -> &str {
-        self
-    }
-}
-
-impl From<char> for Str {
-    fn from(c: char) -> Self {
-        Self(c.into())
-    }
-}
-
-impl From<&str> for Str {
-    fn from(s: &str) -> Self {
-        Self(s.into())
-    }
-}
-
-impl From<String> for Str {
-    fn from(s: String) -> Self {
-        Self(s.into())
-    }
-}
-
-impl From<EcoString> for Str {
-    fn from(s: EcoString) -> Self {
-        Self(s)
-    }
-}
-
-impl From<&EcoString> for Str {
-    fn from(s: &EcoString) -> Self {
-        Self(s.clone())
-    }
-}
-
-impl From<Str> for EcoString {
-    fn from(s: Str) -> Self {
-        s.0
-    }
-}
-
-impl From<&Str> for EcoString {
-    fn from(s: &Str) -> Self {
-        s.0.clone()
-    }
-}
diff --git a/src/eval/template.rs b/src/eval/template.rs
index 2622a1f0..18104638 100644
--- a/src/eval/template.rs
+++ b/src/eval/template.rs
@@ -5,7 +5,6 @@ use std::mem;
 use std::ops::{Add, AddAssign};
 use std::rc::Rc;
 
-use super::Str;
 use crate::diag::StrResult;
 use crate::geom::{Align, Dir, GenAxis, Length, Linear, Sides, Size};
 use crate::layout::{BlockLevel, BlockNode, InlineLevel, InlineNode, PageNode};
@@ -214,20 +213,20 @@ impl AddAssign for Template {
     }
 }
 
-impl Add<Str> for Template {
+impl Add<EcoString> for Template {
     type Output = Self;
 
-    fn add(mut self, rhs: Str) -> Self::Output {
-        Rc::make_mut(&mut self.0).push(TemplateNode::Text(rhs.into()));
+    fn add(mut self, rhs: EcoString) -> Self::Output {
+        Rc::make_mut(&mut self.0).push(TemplateNode::Text(rhs));
         self
     }
 }
 
-impl Add<Template> for Str {
+impl Add<Template> for EcoString {
     type Output = Template;
 
     fn add(self, mut rhs: Template) -> Self::Output {
-        Rc::make_mut(&mut rhs.0).insert(0, TemplateNode::Text(self.into()));
+        Rc::make_mut(&mut rhs.0).insert(0, TemplateNode::Text(self));
         rhs
     }
 }
@@ -491,7 +490,7 @@ impl ParBuilder {
                 self.children.last_mut()
             {
                 if prev_align == curr_align && Rc::ptr_eq(prev_props, curr_props) {
-                    prev_text.push_str(&curr_text);
+                    prev_text.push_str(curr_text);
                     return;
                 }
             }
diff --git a/src/eval/value.rs b/src/eval/value.rs
index 804f8d55..0fcc4bfc 100644
--- a/src/eval/value.rs
+++ b/src/eval/value.rs
@@ -3,7 +3,7 @@ use std::cmp::Ordering;
 use std::fmt::{self, Debug, Formatter};
 use std::rc::Rc;
 
-use super::{ops, Array, Dict, Function, Str, Template};
+use super::{ops, Array, Dict, Function, Template};
 use crate::diag::StrResult;
 use crate::geom::{Angle, Color, Fractional, Length, Linear, Relative, RgbaColor};
 use crate::syntax::Spanned;
@@ -35,7 +35,7 @@ pub enum Value {
     /// A color value: `#f79143ff`.
     Color(Color),
     /// A string: `"string"`.
-    Str(Str),
+    Str(EcoString),
     /// An array of values: `(1, "hi", 12cm)`.
     Array(Array),
     /// A dictionary value: `(color: #f79143, pattern: dashed)`.
@@ -63,7 +63,7 @@ impl Value {
             Self::Linear(_) => Linear::TYPE_NAME,
             Self::Fractional(_) => Fractional::TYPE_NAME,
             Self::Color(_) => Color::TYPE_NAME,
-            Self::Str(_) => Str::TYPE_NAME,
+            Self::Str(_) => EcoString::TYPE_NAME,
             Self::Array(_) => Array::TYPE_NAME,
             Self::Dict(_) => Dict::TYPE_NAME,
             Self::Template(_) => Template::TYPE_NAME,
@@ -81,8 +81,8 @@ impl Value {
     }
 
     /// Return the debug representation of the value.
-    pub fn repr(&self) -> Str {
-        format_str!("{:?}", self)
+    pub fn repr(&self) -> EcoString {
+        format_eco!("{:?}", self)
     }
 
     /// Join the value with another value.
@@ -163,17 +163,12 @@ impl From<String> for Value {
     }
 }
 
-impl From<EcoString> for Value {
-    fn from(v: EcoString) -> Self {
-        Self::Str(v.into())
-    }
-}
-
 impl From<Dynamic> for Value {
     fn from(v: Dynamic) -> Self {
         Self::Dyn(v)
     }
 }
+
 /// A dynamic value.
 #[derive(Clone)]
 pub struct Dynamic(Rc<dyn Bounds>);
@@ -338,7 +333,8 @@ macro_rules! dynamic {
         }
 
         castable! {
-            $type: <Self as $crate::eval::Type>::TYPE_NAME,
+            $type,
+            Expected: <Self as $crate::eval::Type>::TYPE_NAME,
             $($tts)*
             @this: Self => this.clone(),
         }
@@ -354,8 +350,8 @@ macro_rules! dynamic {
 /// Make a type castable from a value.
 macro_rules! castable {
     (
-        $type:ty:
-        $expected:expr,
+        $type:ty,
+        Expected: $expected:expr,
         $($pattern:pat => $out:expr,)*
         $(@$dyn_in:ident: $dyn_type:ty => $dyn_out:expr,)*
     ) => {
@@ -398,7 +394,7 @@ primitive! { Relative: "relative", Relative }
 primitive! { Linear: "linear", Linear, Length(v) => v.into(), Relative(v) => v.into() }
 primitive! { Fractional: "fractional", Fractional }
 primitive! { Color: "color", Color }
-primitive! { Str: "string", Str }
+primitive! { EcoString: "string", Str }
 primitive! { Array: "array", Array }
 primitive! { Dict: "dictionary", Dict }
 primitive! { Template: "template", Template }
diff --git a/src/eval/walk.rs b/src/eval/walk.rs
index aab32f40..6d5df5ba 100644
--- a/src/eval/walk.rs
+++ b/src/eval/walk.rs
@@ -1,12 +1,12 @@
 use std::rc::Rc;
 
-use super::{Eval, EvalContext, Str, Template, Value};
+use super::{Eval, EvalContext, Template, Value};
 use crate::diag::TypResult;
 use crate::geom::Spec;
 use crate::layout::BlockLevel;
 use crate::library::{GridNode, ParChild, ParNode, TrackSizing};
 use crate::syntax::ast::*;
-use crate::util::BoolExt;
+use crate::util::{BoolExt, EcoString};
 
 /// Walk markup, filling the currently built template.
 pub trait Walk {
@@ -39,8 +39,8 @@ impl Walk for MarkupNode {
             Self::Enum(enum_) => enum_.walk(ctx)?,
             Self::Expr(expr) => match expr.eval(ctx)? {
                 Value::None => {}
-                Value::Int(v) => ctx.template.text(format_str!("{}", v)),
-                Value::Float(v) => ctx.template.text(format_str!("{}", v)),
+                Value::Int(v) => ctx.template.text(format_eco!("{}", v)),
+                Value::Float(v) => ctx.template.text(format_eco!("{}", v)),
                 Value::Str(v) => ctx.template.text(v),
                 Value::Template(v) => ctx.template += v,
                 // For values which can't be shown "naturally", we print the
@@ -108,7 +108,7 @@ impl Walk for HeadingNode {
 impl Walk for ListNode {
     fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
         let body = self.body().eval(ctx)?;
-        walk_item(ctx, Str::from('•'), body);
+        walk_item(ctx, EcoString::from('•'), body);
         Ok(())
     }
 }
@@ -116,19 +116,19 @@ impl Walk for ListNode {
 impl Walk for EnumNode {
     fn walk(&self, ctx: &mut EvalContext) -> TypResult<()> {
         let body = self.body().eval(ctx)?;
-        let label = format_str!("{}.", self.number().unwrap_or(1));
+        let label = format_eco!("{}.", self.number().unwrap_or(1));
         walk_item(ctx, label, body);
         Ok(())
     }
 }
 
-fn walk_item(ctx: &mut EvalContext, label: Str, body: Template) {
+fn walk_item(ctx: &mut EvalContext, label: EcoString, body: Template) {
     ctx.template += Template::from_block(move |style| {
         let label = ParNode {
             dir: style.dir,
             leading: style.leading(),
             children: vec![ParChild::Text(
-                (&label).into(),
+                label.clone(),
                 style.aligns.inline,
                 Rc::clone(&style.text),
             )],
@@ -138,7 +138,7 @@ fn walk_item(ctx: &mut EvalContext, label: Str, body: Template) {
         GridNode {
             tracks: Spec::new(vec![TrackSizing::Auto; 2], vec![]),
             gutter: Spec::new(vec![TrackSizing::Linear(spacing.into())], vec![]),
-            children: vec![label.pack(), body.to_stack(&style).pack()],
+            children: vec![label.pack(), body.to_stack(style).pack()],
         }
     });
 }
diff --git a/src/export/pdf.rs b/src/export/pdf.rs
index 5649d552..d517aadf 100644
--- a/src/export/pdf.rs
+++ b/src/export/pdf.rs
@@ -100,7 +100,7 @@ impl<'a> PdfExporter<'a> {
         let mut resources = pages.resources();
         let mut fonts = resources.fonts();
         for (refs, f) in self.refs.fonts().zip(self.font_map.pdf_indices()) {
-            let name = format!("F{}", f);
+            let name = format_eco!("F{}", f);
             fonts.pair(Name(name.as_bytes()), refs.type0_font);
         }
 
@@ -108,7 +108,7 @@ impl<'a> PdfExporter<'a> {
 
         let mut images = resources.x_objects();
         for (id, im) in self.refs.images().zip(self.image_map.pdf_indices()) {
-            let name = format!("Im{}", im);
+            let name = format_eco!("Im{}", im);
             images.pair(Name(name.as_bytes()), id);
         }
 
@@ -153,7 +153,7 @@ impl<'a> PdfExporter<'a> {
 
     fn write_pages(&mut self) {
         for (id, page) in self.refs.contents().zip(self.frames) {
-            self.write_page(id, &page);
+            self.write_page(id, page);
         }
     }
 
@@ -199,7 +199,7 @@ impl<'a> PdfExporter<'a> {
                         face_id = Some(text.face_id);
                         size = text.size;
 
-                        let name = format!("F{}", self.font_map.map(text.face_id));
+                        let name = format_eco!("F{}", self.font_map.map(text.face_id));
                         content.set_font(Name(name.as_bytes()), size.to_pt() as f32);
                     }
 
@@ -541,7 +541,7 @@ fn encode_image(img: &Image) -> ImageResult<(Vec<u8>, Filter, ColorSpace)> {
 
         // 8-bit gray PNG.
         (ImageFormat::Png, DynamicImage::ImageLuma8(luma)) => {
-            let data = deflate(&luma.as_raw());
+            let data = deflate(luma.as_raw());
             (data, Filter::FlateDecode, ColorSpace::DeviceGray)
         }
 
diff --git a/src/export/subset.rs b/src/export/subset.rs
index 4b6fef8e..b58e042e 100644
--- a/src/export/subset.rs
+++ b/src/export/subset.rs
@@ -36,7 +36,7 @@ struct Subsetter<'a> {
 impl<'a> Subsetter<'a> {
     /// Parse the font header and create a new subsetter.
     fn new(data: &'a [u8], index: u32, glyphs: &'a HashSet<u16>) -> Option<Self> {
-        let mut s = Stream::new(&data);
+        let mut s = Stream::new(data);
 
         let mut magic = s.read::<Magic>()?;
         if magic == Magic::Collection {
@@ -46,7 +46,7 @@ impl<'a> Subsetter<'a> {
             let offsets = s.read_array32::<Offset32>(num_faces)?;
             let offset = offsets.get(index)?.to_usize();
 
-            s = Stream::new_at(&data, offset)?;
+            s = Stream::new_at(data, offset)?;
             magic = s.read::<Magic>()?;
             if magic == Magic::Collection {
                 return None;
@@ -117,7 +117,7 @@ impl<'a> Subsetter<'a> {
             let len = data.len();
             w.write(TableRecord {
                 tag: *tag,
-                checksum: checksum(&data),
+                checksum: checksum(data),
                 offset: offset as u32,
                 length: len as u32,
             });
diff --git a/src/font.rs b/src/font.rs
index 6b76eda6..fb93d5c9 100644
--- a/src/font.rs
+++ b/src/font.rs
@@ -317,30 +317,6 @@ pub enum VerticalFontMetric {
     Linear(Linear),
 }
 
-/// A generic or named font family.
-#[derive(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),
-}
-
-impl Debug for FontFamily {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        f.pad(match self {
-            Self::Serif => "serif",
-            Self::SansSerif => "sans-serif",
-            Self::Monospace => "monospace",
-            Self::Named(s) => s,
-        })
-    }
-}
-
 /// Properties of a single font face.
 #[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct FaceInfo {
diff --git a/src/lib.rs b/src/lib.rs
index 033230f0..895430a2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -28,6 +28,8 @@
 //! [PDF]: export::pdf
 
 #[macro_use]
+pub mod util;
+#[macro_use]
 pub mod diag;
 #[macro_use]
 pub mod eval;
@@ -43,7 +45,6 @@ pub mod parse;
 pub mod source;
 pub mod style;
 pub mod syntax;
-pub mod util;
 
 use std::rc::Rc;
 
@@ -182,7 +183,7 @@ impl ContextBuilder {
             loader,
             #[cfg(feature = "layout-cache")]
             layouts: LayoutCache::new(self.policy, self.max_size),
-            std: self.std.unwrap_or(library::new()),
+            std: self.std.unwrap_or_else(library::new),
             style: self.style.unwrap_or_default(),
         }
     }
diff --git a/src/library/deco.rs b/src/library/deco.rs
index 18ca2bb1..6ef5a97b 100644
--- a/src/library/deco.rs
+++ b/src/library/deco.rs
@@ -36,14 +36,14 @@ fn line_impl(args: &mut Args, kind: LineKind) -> TypResult<Value> {
 
 /// `link`: Typeset text as a link.
 pub fn link(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    let url = args.expect::<Str>("url")?;
+    let url = args.expect::<EcoString>("url")?;
     let body = args.find().unwrap_or_else(|| {
         let mut template = Template::new();
         template.text(url.trim_start_matches("mailto:").trim_start_matches("tel:"));
         template
     });
 
-    Ok(Value::Template(body.decorate(Decoration::Link(url.into()))))
+    Ok(Value::Template(body.decorate(Decoration::Link(url))))
 }
 
 /// A decoration for a frame.
diff --git a/src/library/grid.rs b/src/library/grid.rs
index af486496..c7e6b8e9 100644
--- a/src/library/grid.rs
+++ b/src/library/grid.rs
@@ -3,7 +3,8 @@ use super::prelude::*;
 /// `grid`: Arrange children into a grid.
 pub fn grid(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     castable! {
-        Vec<TrackSizing>: "integer or (auto, linear, fractional, or array thereof)",
+        Vec<TrackSizing>,
+        Expected: "integer or (auto, linear, fractional, or array thereof)",
         Value::Auto => vec![TrackSizing::Auto],
         Value::Length(v) => vec![TrackSizing::Linear(v.into())],
         Value::Relative(v) => vec![TrackSizing::Linear(v.into())],
@@ -17,7 +18,8 @@ pub fn grid(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        TrackSizing: "auto, linear, or fractional",
+        TrackSizing,
+        Expected: "auto, linear, or fractional",
         Value::Auto => Self::Auto,
         Value::Length(v) => Self::Linear(v.into()),
         Value::Relative(v) => Self::Linear(v.into()),
@@ -43,10 +45,7 @@ pub fn grid(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
         GridNode {
             tracks: tracks.clone(),
             gutter: gutter.clone(),
-            children: children
-                .iter()
-                .map(|child| child.to_stack(&style).pack())
-                .collect(),
+            children: children.iter().map(|child| child.to_stack(style).pack()).collect(),
         }
     })))
 }
diff --git a/src/library/image.rs b/src/library/image.rs
index c2273502..b51e4e70 100644
--- a/src/library/image.rs
+++ b/src/library/image.rs
@@ -6,7 +6,7 @@ use crate::image::ImageId;
 
 /// `image`: An image.
 pub fn image(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    let path = args.expect::<Spanned<Str>>("path to image file")?;
+    let path = args.expect::<Spanned<EcoString>>("path to image file")?;
     let width = args.named("width")?;
     let height = args.named("height")?;
 
diff --git a/src/library/mod.rs b/src/library/mod.rs
index b0a42e83..e6cb0d9d 100644
--- a/src/library/mod.rs
+++ b/src/library/mod.rs
@@ -23,12 +23,12 @@ mod prelude {
     pub use std::rc::Rc;
 
     pub use crate::diag::{At, TypResult};
-    pub use crate::eval::{Args, EvalContext, Str, Template, Value};
+    pub use crate::eval::{Args, EvalContext, Template, Value};
     pub use crate::frame::*;
     pub use crate::geom::*;
     pub use crate::layout::*;
     pub use crate::syntax::{Span, Spanned};
-    pub use crate::util::OptionExt;
+    pub use crate::util::{EcoString, OptionExt};
 }
 
 pub use self::image::*;
@@ -47,8 +47,8 @@ pub use transform::*;
 pub use utility::*;
 
 use crate::eval::{Scope, Value};
-use crate::font::FontFamily;
 use crate::geom::*;
+use crate::style::FontFamily;
 
 /// Construct a scope containing all standard library definitions.
 pub fn new() -> Scope {
diff --git a/src/library/pad.rs b/src/library/pad.rs
index 6457f603..8c3c0f53 100644
--- a/src/library/pad.rs
+++ b/src/library/pad.rs
@@ -19,7 +19,7 @@ pub fn pad(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     Ok(Value::Template(Template::from_block(move |style| {
         PadNode {
             padding,
-            child: body.to_stack(&style).pack(),
+            child: body.to_stack(style).pack(),
         }
     })))
 }
diff --git a/src/library/page.rs b/src/library/page.rs
index b31a32a3..16e6283d 100644
--- a/src/library/page.rs
+++ b/src/library/page.rs
@@ -4,7 +4,8 @@ use crate::style::{Paper, PaperClass};
 /// `page`: Configure pages.
 pub fn page(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     castable! {
-        Paper: "string",
+        Paper,
+        Expected: "string",
         Value::Str(string) => Paper::from_name(&string).ok_or("unknown paper")?,
     }
 
diff --git a/src/library/par.rs b/src/library/par.rs
index 3330eedf..eeb46dd8 100644
--- a/src/library/par.rs
+++ b/src/library/par.rs
@@ -34,7 +34,7 @@ pub fn par(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 
 /// `lang`: Configure the language.
 pub fn lang(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    let iso = args.find::<Str>();
+    let iso = args.find::<EcoString>();
     let dir = if let Some(dir) = args.named::<Spanned<Dir>>("dir")? {
         if dir.v.axis() == SpecAxis::Horizontal {
             Some(dir.v)
diff --git a/src/library/spacing.rs b/src/library/spacing.rs
index 23328c86..26f1bee1 100644
--- a/src/library/spacing.rs
+++ b/src/library/spacing.rs
@@ -24,7 +24,8 @@ pub enum Spacing {
 }
 
 castable! {
-    Spacing: "linear or fractional",
+    Spacing,
+    Expected: "linear or fractional",
     Value::Length(v) => Self::Linear(v.into()),
     Value::Relative(v) => Self::Linear(v.into()),
     Value::Linear(v) => Self::Linear(v),
diff --git a/src/library/stack.rs b/src/library/stack.rs
index 80ed507b..ffd9b44f 100644
--- a/src/library/stack.rs
+++ b/src/library/stack.rs
@@ -11,7 +11,8 @@ pub fn stack(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        Child: "linear, fractional or template",
+        Child,
+        Expected: "linear, fractional or template",
         Value::Length(v) => Self::Spacing(Spacing::Linear(v.into())),
         Value::Relative(v) => Self::Spacing(Spacing::Linear(v.into())),
         Value::Linear(v) => Self::Spacing(Spacing::Linear(v)),
diff --git a/src/library/text.rs b/src/library/text.rs
index 4cf94bde..914122a1 100644
--- a/src/library/text.rs
+++ b/src/library/text.rs
@@ -7,48 +7,42 @@ use ttf_parser::Tag;
 
 use super::prelude::*;
 use crate::font::{
-    Face, FaceId, FontFamily, FontStore, FontStretch, FontStyle, FontVariant, FontWeight,
+    Face, FaceId, FontStore, FontStretch, FontStyle, FontVariant, FontWeight,
     VerticalFontMetric,
 };
 use crate::geom::{Dir, Em, Length, Point, Size};
 use crate::style::{
-    FontFeatures, NumberPosition, NumberType, NumberWidth, Style, TextStyle,
+    FontFamily, FontFeatures, NumberPosition, NumberType, NumberWidth, Style,
+    StylisticSet, TextStyle,
 };
-use crate::util::SliceExt;
+use crate::util::{EcoString, SliceExt};
 
 /// `font`: Configure the font.
 pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    struct FontDef(Rc<Vec<FontFamily>>);
-    struct FamilyDef(Rc<Vec<String>>);
-    struct FeatureList(Vec<(Tag, u32)>);
-    struct StylisticSet(Option<u8>);
-
     castable! {
-        FontDef: "font family or array of font families",
-        Value::Str(string) => Self(Rc::new(vec![FontFamily::Named(string.to_lowercase())])),
-        Value::Array(values) => Self(Rc::new(
-            values
-                .into_iter()
-                .filter_map(|v| v.cast().ok())
-                .collect()
-        )),
-        @family: FontFamily => Self(Rc::new(vec![family.clone()])),
+        Vec<FontFamily>,
+        Expected: "string, generic family or array thereof",
+        Value::Str(string) => vec![FontFamily::Named(string.to_lowercase())],
+        Value::Array(values) => {
+            values.into_iter().filter_map(|v| v.cast().ok()).collect()
+        },
+        @family: FontFamily => vec![family.clone()],
     }
 
     castable! {
-        FamilyDef: "string or array of strings",
-        Value::Str(string) => Self(Rc::new(vec![string.to_lowercase()])),
-        Value::Array(values) => Self(Rc::new(
-            values
-                .into_iter()
-                .filter_map(|v| v.cast().ok())
-                .map(|string: Str| string.to_lowercase())
-                .collect()
-        )),
+        Vec<EcoString>,
+        Expected: "string or array of strings",
+        Value::Str(string) => vec![string.to_lowercase()],
+        Value::Array(values) => values
+            .into_iter()
+            .filter_map(|v| v.cast().ok())
+            .map(|string: EcoString| string.to_lowercase())
+            .collect(),
     }
 
     castable! {
-        FontStyle: "string",
+        FontStyle,
+        Expected: "string",
         Value::Str(string) => match string.as_str() {
             "normal" => Self::Normal,
             "italic" => Self::Italic,
@@ -58,7 +52,8 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        FontWeight: "integer or string",
+        FontWeight,
+        Expected: "integer or string",
         Value::Int(v) => v.try_into().map_or(Self::BLACK, Self::from_number),
         Value::Str(string) => match string.as_str() {
             "thin" => Self::THIN,
@@ -75,12 +70,14 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        FontStretch: "relative",
+        FontStretch,
+        Expected: "relative",
         Value::Relative(v) => Self::from_ratio(v.get() as f32),
     }
 
     castable! {
-        VerticalFontMetric: "linear or string",
+        VerticalFontMetric,
+        Expected: "linear or string",
         Value::Length(v) => Self::Linear(v.into()),
         Value::Relative(v) => Self::Linear(v.into()),
         Value::Linear(v) => Self::Linear(v),
@@ -95,7 +92,8 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        StylisticSet: "none or integer",
+        StylisticSet,
+        Expected: "none or integer",
         Value::None => Self(None),
         Value::Int(v) => match v {
             1 ..= 20 => Self(Some(v as u8)),
@@ -104,7 +102,8 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        NumberType: "auto or string",
+        NumberType,
+        Expected: "auto or string",
         Value::Auto => Self::Auto,
         Value::Str(string) => match string.as_str() {
             "lining" => Self::Lining,
@@ -114,7 +113,8 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        NumberWidth: "auto or string",
+        NumberWidth,
+        Expected: "auto or string",
         Value::Auto => Self::Auto,
         Value::Str(string) => match string.as_str() {
             "proportional" => Self::Proportional,
@@ -124,7 +124,8 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        NumberPosition: "string",
+        NumberPosition,
+        Expected: "string",
         Value::Str(string) => match string.as_str() {
             "normal" => Self::Normal,
             "subscript" => Self::Subscript,
@@ -134,44 +135,39 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }
 
     castable! {
-        FeatureList: "array of strings or dictionary mapping tags to integers",
-        Value::Array(values) => Self(
-            values
-                .into_iter()
-                .filter_map(|v| v.cast().ok())
-                .map(|string: Str| (Tag::from_bytes_lossy(string.as_bytes()), 1))
-                .collect()
-        ),
-        Value::Dict(values) => Self(
-            values
-                .into_iter()
-                .filter_map(|(k, v)| {
-                    let tag = Tag::from_bytes_lossy(k.as_bytes());
-                    let num = v.cast::<i64>().ok()?.try_into().ok()?;
-                    Some((tag, num))
-                })
-                .collect()
-        ),
+        Vec<(Tag, u32)>,
+        Expected: "array of strings or dictionary mapping tags to integers",
+        Value::Array(values) => values
+            .into_iter()
+            .filter_map(|v| v.cast().ok())
+            .map(|string: EcoString| (Tag::from_bytes_lossy(string.as_bytes()), 1))
+            .collect(),
+        Value::Dict(values) => values
+            .into_iter()
+            .filter_map(|(k, v)| {
+                let tag = Tag::from_bytes_lossy(k.as_bytes());
+                let num = v.cast::<i64>().ok()?.try_into().ok()?;
+                Some((tag, num))
+            })
+            .collect(),
     }
 
     let list = args.named("family")?.or_else(|| {
         let families: Vec<_> = args.all().collect();
-        (!families.is_empty()).then(|| FontDef(Rc::new(families)))
+        (!families.is_empty()).then(|| families)
     });
 
     let serif = args.named("serif")?;
     let sans_serif = args.named("sans-serif")?;
     let monospace = args.named("monospace")?;
     let fallback = args.named("fallback")?;
-
-    let size = args.named::<Linear>("size")?.or_else(|| args.find());
     let style = args.named("style")?;
     let weight = args.named("weight")?;
     let stretch = args.named("stretch")?;
-    let fill = args.named("fill")?.or_else(|| args.find());
+    let size = args.named::<Linear>("size")?.or_else(|| args.find());
     let top_edge = args.named("top-edge")?;
     let bottom_edge = args.named("bottom-edge")?;
-
+    let fill = args.named("fill")?.or_else(|| args.find());
     let kerning = args.named("kerning")?;
     let smallcaps = args.named("smallcaps")?;
     let alternates = args.named("alternates")?;
@@ -199,22 +195,6 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     let f = move |style_: &mut Style| {
         let text = style_.text_mut();
 
-        if let Some(FontDef(list)) = &list {
-            text.families_mut().list = list.clone();
-        }
-
-        if let Some(FamilyDef(serif)) = &serif {
-            text.families_mut().serif = serif.clone();
-        }
-
-        if let Some(FamilyDef(sans_serif)) = &sans_serif {
-            text.families_mut().sans_serif = sans_serif.clone();
-        }
-
-        if let Some(FamilyDef(monospace)) = &monospace {
-            text.families_mut().monospace = monospace.clone();
-        }
-
         if let Some(size) = size {
             text.size = size.resolve(text.size);
         }
@@ -223,16 +203,21 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
             text.fill = Paint::Color(fill);
         }
 
-        set!(text.fallback => fallback);
         set!(text.variant.style => style);
         set!(text.variant.weight => weight);
         set!(text.variant.stretch => stretch);
         set!(text.top_edge => top_edge);
         set!(text.bottom_edge => bottom_edge);
+        set!(text.fallback => fallback);
 
+        set!(text.families_mut().list => list.clone());
+        set!(text.families_mut().serif => serif.clone());
+        set!(text.families_mut().sans_serif => sans_serif.clone());
+        set!(text.families_mut().monospace => monospace.clone());
         set!(text.features_mut().kerning => kerning);
         set!(text.features_mut().smallcaps => smallcaps);
         set!(text.features_mut().alternates => alternates);
+        set!(text.features_mut().stylistic_set => stylistic_set);
         set!(text.features_mut().ligatures.standard => ligatures);
         set!(text.features_mut().ligatures.discretionary => discretionary_ligatures);
         set!(text.features_mut().ligatures.historical => historical_ligatures);
@@ -241,14 +226,7 @@ pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
         set!(text.features_mut().numbers.position => number_position);
         set!(text.features_mut().numbers.slashed_zero => slashed_zero);
         set!(text.features_mut().numbers.fractions => fractions);
-
-        if let Some(StylisticSet(stylistic_set)) = stylistic_set {
-            text.features_mut().stylistic_set = stylistic_set;
-        }
-
-        if let Some(FeatureList(features)) = &features {
-            text.features_mut().raw = features.clone();
-        }
+        set!(text.features_mut().raw => features.clone());
     };
 
     Ok(if let Some(body) = body {
@@ -638,12 +616,10 @@ fn tags(features: &FontFeatures) -> Vec<Feature> {
         feat(b"salt", 1);
     }
 
-    let set_tag;
-    if let Some(set) = features.stylistic_set {
-        if matches!(set, 1 ..= 20) {
-            set_tag = [b's', b's', b'0' + set / 10, b'0' + set % 10];
-            feat(&set_tag, 1);
-        }
+    let storage;
+    if let StylisticSet(Some(set @ 1 ..= 20)) = features.stylistic_set {
+        storage = [b's', b's', b'0' + set / 10, b'0' + set % 10];
+        feat(&storage, 1);
     }
 
     if !features.ligatures.standard {
diff --git a/src/library/utility.rs b/src/library/utility.rs
index 69ae235d..6d15a823 100644
--- a/src/library/utility.rs
+++ b/src/library/utility.rs
@@ -77,8 +77,8 @@ pub fn float(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 pub fn str(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("value")?;
     Ok(Value::Str(match v {
-        Value::Int(v) => format_str!("{}", v),
-        Value::Float(v) => format_str!("{}", v),
+        Value::Int(v) => format_eco!("{}", v),
+        Value::Float(v) => format_eco!("{}", v),
         Value::Str(v) => v,
         v => bail!(span, "cannot convert {} to string", v.type_name()),
     }))
@@ -87,7 +87,7 @@ pub fn str(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 /// `rgb`: Create an RGB(A) color.
 pub fn rgb(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     Ok(Value::Color(Color::Rgba(
-        if let Some(string) = args.find::<Spanned<Str>>() {
+        if let Some(string) = args.find::<Spanned<EcoString>>() {
             match RgbaColor::from_str(&string.v) {
                 Ok(color) => color,
                 Err(_) => bail!(string.span, "invalid hex string"),
@@ -98,7 +98,7 @@ pub fn rgb(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
             let b = args.expect("blue component")?;
             let a = args.eat()?.unwrap_or(Spanned::new(1.0, Span::detached()));
             let f = |Spanned { v, span }: Spanned<f64>| {
-                if 0.0 <= v && v <= 1.0 {
+                if (0.0 ..= 1.0).contains(&v) {
                     Ok((v * 255.0).round() as u8)
                 } else {
                     bail!(span, "value must be between 0.0 and 1.0");
@@ -182,19 +182,19 @@ pub fn range(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 
 /// `lower`: Convert a string to lowercase.
 pub fn lower(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    Ok(args.expect::<Str>("string")?.to_lowercase().into())
+    Ok(args.expect::<EcoString>("string")?.to_lowercase().into())
 }
 
 /// `upper`: Convert a string to uppercase.
 pub fn upper(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    Ok(args.expect::<Str>("string")?.to_uppercase().into())
+    Ok(args.expect::<EcoString>("string")?.to_uppercase().into())
 }
 
 /// `len`: The length of a string, an array or a dictionary.
 pub fn len(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("collection")?;
     Ok(Value::Int(match v {
-        Value::Str(v) => v.len(),
+        Value::Str(v) => v.len() as i64,
         Value::Array(v) => v.len(),
         Value::Dict(v) => v.len(),
         v => bail!(
diff --git a/src/loading/fs.rs b/src/loading/fs.rs
index ed544ba7..12996a69 100644
--- a/src/loading/fs.rs
+++ b/src/loading/fs.rs
@@ -119,7 +119,7 @@ impl FsLoader {
         let path = path.strip_prefix(".").unwrap_or(path);
         if let Ok(file) = File::open(path) {
             if let Ok(mmap) = unsafe { Mmap::map(&file) } {
-                self.faces.extend(FaceInfo::parse(&path, &mmap));
+                self.faces.extend(FaceInfo::parse(path, &mmap));
             }
         }
     }
diff --git a/src/parse/parser.rs b/src/parse/parser.rs
index 1c4c2a5c..6598b1f2 100644
--- a/src/parse/parser.rs
+++ b/src/parse/parser.rs
@@ -242,7 +242,7 @@ impl<'s> Parser<'s> {
                 self.eat();
                 rescan = false;
             } else if required {
-                self.push_error(format!("expected {}", end));
+                self.push_error(format_eco!("expected {}", end));
             }
         }
 
@@ -327,8 +327,8 @@ impl Parser<'_> {
     pub fn unexpected(&mut self) {
         match self.peek() {
             Some(found) => {
-                let msg = format!("unexpected {}", found);
-                let error = NodeKind::Error(ErrorPos::Full, msg.into());
+                let msg = format_eco!("unexpected {}", found);
+                let error = NodeKind::Error(ErrorPos::Full, msg);
                 self.perform(error, Self::eat);
             }
             None => self.push_error("unexpected end of file"),
@@ -339,8 +339,8 @@ impl Parser<'_> {
     pub fn expected(&mut self, thing: &str) {
         match self.peek() {
             Some(found) => {
-                let msg = format!("expected {}, found {}", thing, found);
-                let error = NodeKind::Error(ErrorPos::Full, msg.into());
+                let msg = format_eco!("expected {}, found {}", thing, found);
+                let error = NodeKind::Error(ErrorPos::Full, msg);
                 self.perform(error, Self::eat);
             }
             None => self.expected_at(thing),
@@ -400,8 +400,8 @@ impl Marker {
 
     /// Insert an error message that `what` was expected at the marker position.
     pub fn expected(self, p: &mut Parser, what: &str) {
-        let msg = format!("expected {}", what);
-        let error = NodeKind::Error(ErrorPos::Full, msg.into());
+        let msg = format_eco!("expected {}", what);
+        let error = NodeKind::Error(ErrorPos::Full, msg);
         p.children.insert(self.0, GreenData::new(error, 0).into());
     }
 
diff --git a/src/parse/scanner.rs b/src/parse/scanner.rs
index ea06a2e0..c735be40 100644
--- a/src/parse/scanner.rs
+++ b/src/parse/scanner.rs
@@ -119,7 +119,7 @@ impl<'s> Scanner<'s> {
     /// The full source string.
     #[inline]
     pub fn src(&self) -> &'s str {
-        &self.src
+        self.src
     }
 
     /// Slice out part of the source string.
diff --git a/src/parse/tokens.rs b/src/parse/tokens.rs
index 96dfd9d1..f80d345e 100644
--- a/src/parse/tokens.rs
+++ b/src/parse/tokens.rs
@@ -239,7 +239,7 @@ impl<'s> Tokens<'s> {
                     self.s.eat_assert('{');
                     let sequence = self.s.eat_while(|c| c.is_ascii_alphanumeric());
                     if self.s.eat_if('}') {
-                        if let Some(c) = resolve_hex(&sequence) {
+                        if let Some(c) = resolve_hex(sequence) {
                             NodeKind::UnicodeEscape(c)
                         } else {
                             NodeKind::Error(
@@ -270,7 +270,7 @@ impl<'s> Tokens<'s> {
                 None => NodeKind::Ident(read.into()),
             }
         } else {
-            NodeKind::Text("#".into())
+            NodeKind::Text('#'.into())
         }
     }
 
@@ -284,7 +284,7 @@ impl<'s> Tokens<'s> {
         } else if self.s.check_or(true, char::is_whitespace) {
             NodeKind::Minus
         } else {
-            NodeKind::Text("-".into())
+            NodeKind::Text('-'.into())
         }
     }
 
@@ -340,7 +340,7 @@ impl<'s> Tokens<'s> {
             NodeKind::Raw(Rc::new(resolve_raw(
                 column,
                 backticks,
-                self.s.get(start .. end).into(),
+                self.s.get(start .. end),
             )))
         } else {
             let remaining = backticks - found;
@@ -349,11 +349,10 @@ impl<'s> Tokens<'s> {
             NodeKind::Error(
                 ErrorPos::End,
                 if found == 0 {
-                    format!("expected {} {}", remaining, noun)
+                    format_eco!("expected {} {}", remaining, noun)
                 } else {
-                    format!("expected {} more {}", remaining, noun)
-                }
-                .into(),
+                    format_eco!("expected {} more {}", remaining, noun)
+                },
             )
         }
     }
@@ -397,11 +396,10 @@ impl<'s> Tokens<'s> {
             NodeKind::Error(
                 ErrorPos::End,
                 if !display || (!escaped && dollar) {
-                    "expected closing dollar sign"
+                    "expected closing dollar sign".into()
                 } else {
-                    "expected closing bracket and dollar sign"
-                }
-                .into(),
+                    "expected closing bracket and dollar sign".into()
+                },
             )
         }
     }
@@ -413,7 +411,7 @@ impl<'s> Tokens<'s> {
             "auto" => NodeKind::Auto,
             "true" => NodeKind::Bool(true),
             "false" => NodeKind::Bool(false),
-            id => keyword(id).unwrap_or(NodeKind::Ident(id.into())),
+            id => keyword(id).unwrap_or_else(|| NodeKind::Ident(id.into())),
         }
     }
 
@@ -461,9 +459,7 @@ impl<'s> Tokens<'s> {
                 "in" => NodeKind::Length(f, LengthUnit::In),
                 "deg" => NodeKind::Angle(f, AngularUnit::Deg),
                 "rad" => NodeKind::Angle(f, AngularUnit::Rad),
-                _ => {
-                    return NodeKind::Unknown(all.into());
-                }
+                _ => NodeKind::Unknown(all.into()),
             }
         } else {
             NodeKind::Unknown(all.into())
diff --git a/src/style/mod.rs b/src/style/mod.rs
index dccc7543..60734716 100644
--- a/src/style/mod.rs
+++ b/src/style/mod.rs
@@ -4,12 +4,14 @@ mod paper;
 
 pub use paper::*;
 
+use std::fmt::{self, Debug, Formatter};
 use std::rc::Rc;
 
 use ttf_parser::Tag;
 
 use crate::font::*;
 use crate::geom::*;
+use crate::util::EcoString;
 
 /// Defines a set of properties a template can be instantiated with.
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
@@ -192,7 +194,7 @@ impl TextStyle {
             &[]
         };
 
-        head.iter().chain(core).chain(tail).map(String::as_str)
+        head.iter().chain(core).chain(tail).map(EcoString::as_str)
     }
 
     /// Access the `families` style mutably.
@@ -232,33 +234,57 @@ impl Default for TextStyle {
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub struct FamilyStyle {
     /// The user-defined list of font families.
-    pub list: Rc<Vec<FontFamily>>,
+    pub list: Vec<FontFamily>,
     /// Definition of serif font families.
-    pub serif: Rc<Vec<String>>,
+    pub serif: Vec<EcoString>,
     /// Definition of sans-serif font families.
-    pub sans_serif: Rc<Vec<String>>,
+    pub sans_serif: Vec<EcoString>,
     /// Definition of monospace font families used for raw text.
-    pub monospace: Rc<Vec<String>>,
+    pub monospace: Vec<EcoString>,
     /// Base fonts that are tried as last resort.
-    pub base: Rc<Vec<String>>,
+    pub base: Vec<EcoString>,
 }
 
 impl Default for FamilyStyle {
     fn default() -> Self {
         Self {
-            list: Rc::new(vec![FontFamily::SansSerif]),
-            serif: Rc::new(vec!["ibm plex serif".into()]),
-            sans_serif: Rc::new(vec!["ibm plex sans".into()]),
-            monospace: Rc::new(vec!["ibm plex mono".into()]),
-            base: Rc::new(vec![
+            list: vec![FontFamily::SansSerif],
+            serif: vec!["ibm plex serif".into()],
+            sans_serif: vec!["ibm plex sans".into()],
+            monospace: vec!["ibm plex mono".into()],
+            base: vec![
                 "ibm plex sans".into(),
                 "latin modern math".into(),
                 "twitter color emoji".into(),
-            ]),
+            ],
         }
     }
 }
 
+/// A generic or named font family.
+#[derive(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(EcoString),
+}
+
+impl Debug for FontFamily {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.pad(match self {
+            Self::Serif => "serif",
+            Self::SansSerif => "sans-serif",
+            Self::Monospace => "monospace",
+            Self::Named(s) => s,
+        })
+    }
+}
+
 /// Whether various kinds of ligatures should appear.
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub struct FontFeatures {
@@ -269,7 +295,7 @@ pub struct FontFeatures {
     /// Whether to apply stylistic alternates. ("salt")
     pub alternates: bool,
     /// Which stylistic set to apply. ("ss01" - "ss20")
-    pub stylistic_set: Option<u8>,
+    pub stylistic_set: StylisticSet,
     /// Configuration of ligature features.
     pub ligatures: LigatureFeatures,
     /// Configuration of numbers features.
@@ -284,7 +310,7 @@ impl Default for FontFeatures {
             kerning: true,
             smallcaps: false,
             alternates: false,
-            stylistic_set: None,
+            stylistic_set: StylisticSet::default(),
             ligatures: LigatureFeatures::default(),
             numbers: NumberFeatures::default(),
             raw: vec![],
@@ -292,6 +318,16 @@ impl Default for FontFeatures {
     }
 }
 
+/// A stylistic set in a font face.
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub struct StylisticSet(pub Option<u8>);
+
+impl Default for StylisticSet {
+    fn default() -> Self {
+        Self(None)
+    }
+}
+
 /// Whether various kinds of ligatures should appear.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub struct LigatureFeatures {
diff --git a/src/syntax/ast.rs b/src/syntax/ast.rs
index 288c749a..0849dd58 100644
--- a/src/syntax/ast.rs
+++ b/src/syntax/ast.rs
@@ -65,9 +65,9 @@ impl Markup {
             NodeKind::Emph => Some(MarkupNode::Emph),
             NodeKind::Text(s) => Some(MarkupNode::Text(s.clone())),
             NodeKind::UnicodeEscape(c) => Some(MarkupNode::Text((*c).into())),
-            NodeKind::EnDash => Some(MarkupNode::Text("\u{2013}".into())),
-            NodeKind::EmDash => Some(MarkupNode::Text("\u{2014}".into())),
-            NodeKind::NonBreakingSpace => Some(MarkupNode::Text("\u{00A0}".into())),
+            NodeKind::EnDash => Some(MarkupNode::Text('\u{2013}'.into())),
+            NodeKind::EmDash => Some(MarkupNode::Text('\u{2014}'.into())),
+            NodeKind::NonBreakingSpace => Some(MarkupNode::Text('\u{00A0}'.into())),
             NodeKind::Math(math) => Some(MarkupNode::Math(math.as_ref().clone())),
             NodeKind::Raw(raw) => Some(MarkupNode::Raw(raw.as_ref().clone())),
             NodeKind::Heading => node.cast().map(MarkupNode::Heading),
@@ -175,7 +175,7 @@ impl EnumNode {
         self.0
             .children()
             .find_map(|node| match node.kind() {
-                NodeKind::EnumNumbering(num) => Some(num.clone()),
+                NodeKind::EnumNumbering(num) => Some(*num),
                 _ => None,
             })
             .expect("enum node is missing number")
diff --git a/src/syntax/mod.rs b/src/syntax/mod.rs
index ca6ed243..6f04cdc9 100644
--- a/src/syntax/mod.rs
+++ b/src/syntax/mod.rs
@@ -30,7 +30,7 @@ impl Green {
     fn data(&self) -> &GreenData {
         match self {
             Green::Node(n) => &n.data,
-            Green::Token(t) => &t,
+            Green::Token(t) => t,
         }
     }
 
@@ -55,7 +55,7 @@ impl Green {
     /// The node's children.
     pub fn children(&self) -> &[Green] {
         match self {
-            Green::Node(n) => &n.children(),
+            Green::Node(n) => n.children(),
             Green::Token(_) => &[],
         }
     }
diff --git a/src/syntax/span.rs b/src/syntax/span.rs
index 47d96589..4d5b8819 100644
--- a/src/syntax/span.rs
+++ b/src/syntax/span.rs
@@ -88,6 +88,11 @@ impl Span {
         Self { end, ..self }
     }
 
+    /// Whether the span is a single point.
+    pub fn is_empty(self) -> bool {
+        self.start == self.end
+    }
+
     /// The byte length of the spanned region.
     pub fn len(self) -> usize {
         self.end - self.start
diff --git a/src/util/eco_string.rs b/src/util/eco_string.rs
index ab8d5642..8cb83377 100644
--- a/src/util/eco_string.rs
+++ b/src/util/eco_string.rs
@@ -2,11 +2,21 @@ use std::borrow::Borrow;
 use std::cmp::Ordering;
 use std::fmt::{self, Debug, Display, Formatter, Write};
 use std::hash::{Hash, Hasher};
-use std::ops::Deref;
+use std::ops::{Add, AddAssign, Deref};
 use std::rc::Rc;
 
 use super::RcExt;
 
+/// Create a new [`EcoString`] from a format string.
+macro_rules! format_eco {
+    ($($tts:tt)*) => {{
+        use std::fmt::Write;
+        let mut s = $crate::util::EcoString::new();
+        write!(s, $($tts)*).unwrap();
+        s
+    }};
+}
+
 /// An economical string with inline storage and clone-on-write semantics.
 #[derive(Clone)]
 pub struct EcoString(Repr);
@@ -142,14 +152,38 @@ impl EcoString {
         }
     }
 
+    /// Convert the string to lowercase.
+    pub fn to_lowercase(&self) -> Self {
+        if let Repr::Small { mut buf, len } = self.0 {
+            if self.is_ascii() {
+                buf[.. usize::from(len)].make_ascii_lowercase();
+                return Self(Repr::Small { buf, len });
+            }
+        }
+
+        self.as_str().to_lowercase().into()
+    }
+
+    /// Convert the string to uppercase.
+    pub fn to_uppercase(&self) -> Self {
+        if let Repr::Small { mut buf, len } = self.0 {
+            if self.is_ascii() {
+                buf[.. usize::from(len)].make_ascii_uppercase();
+                return Self(Repr::Small { buf, len });
+            }
+        }
+
+        self.as_str().to_uppercase().into()
+    }
+
     /// Repeat this string `n` times.
     pub fn repeat(&self, n: usize) -> Self {
         if n == 0 {
             return Self::new();
         }
 
-        if let Repr::Small { buf, len } = &self.0 {
-            let prev = usize::from(*len);
+        if let Repr::Small { buf, len } = self.0 {
+            let prev = usize::from(len);
             let new = prev.saturating_mul(n);
             if new <= LIMIT {
                 let src = &buf[.. prev];
@@ -193,7 +227,18 @@ impl Default for EcoString {
 
 impl Debug for EcoString {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        Debug::fmt(self.as_str(), f)
+        f.write_char('"')?;
+        for c in self.chars() {
+            match c {
+                '\\' => f.write_str(r"\\")?,
+                '"' => f.write_str(r#"\""#)?,
+                '\n' => f.write_str(r"\n")?,
+                '\r' => f.write_str(r"\r")?,
+                '\t' => f.write_str(r"\t")?,
+                _ => f.write_char(c)?,
+            }
+        }
+        f.write_char('"')
     }
 }
 
@@ -253,6 +298,21 @@ impl Write for EcoString {
     }
 }
 
+impl Add for EcoString {
+    type Output = Self;
+
+    fn add(mut self, rhs: Self) -> Self::Output {
+        self += rhs;
+        self
+    }
+}
+
+impl AddAssign for EcoString {
+    fn add_assign(&mut self, rhs: Self) {
+        self.push_str(rhs.as_str());
+    }
+}
+
 impl AsRef<str> for EcoString {
     fn as_ref(&self) -> &str {
         self
@@ -383,6 +443,21 @@ mod tests {
     }
 
     #[test]
+    fn test_str_case() {
+        assert_eq!(EcoString::new().to_uppercase(), "");
+        assert_eq!(EcoString::from("abc").to_uppercase(), "ABC");
+        assert_eq!(EcoString::from("AΣ").to_lowercase(), "aς");
+        assert_eq!(
+            EcoString::from("a").repeat(100).to_uppercase(),
+            EcoString::from("A").repeat(100)
+        );
+        assert_eq!(
+            EcoString::from("Ö").repeat(20).to_lowercase(),
+            EcoString::from("ö").repeat(20)
+        );
+    }
+
+    #[test]
     fn test_str_repeat() {
         // Test with empty string.
         assert_eq!(EcoString::new().repeat(0), "");
diff --git a/src/util/mod.rs b/src/util/mod.rs
index c4272c55..8b74aed6 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -1,5 +1,6 @@
 //! Utilities.
 
+#[macro_use]
 mod eco_string;
 mod mac_roman;