Set Rules Episode VII: The Set Awakens

17 files changed, 471 insertions, 246 deletions

diff --git a/src/eval/class.rs b/src/eval/class.rs
new file mode 100644
index 00000000..45674933
--- /dev/null
+++ b/src/eval/class.rs
@@ -0,0 +1,101 @@
+use std::fmt::{self, Debug, Formatter, Write};
+use std::marker::PhantomData;
+use std::rc::Rc;
+
+use super::{Args, EvalContext, Node, Styles};
+use crate::diag::TypResult;
+use crate::util::EcoString;
+
+/// A class of nodes.
+#[derive(Clone)]
+pub struct Class(Rc<Inner<dyn Bounds>>);
+
+/// The unsized structure behind the [`Rc`].
+struct Inner<T: ?Sized> {
+    name: EcoString,
+    dispatch: T,
+}
+
+impl Class {
+    /// Create a new class.
+    pub fn new<T>(name: EcoString) -> Self
+    where
+        T: Construct + Set + 'static,
+    {
+        Self(Rc::new(Inner {
+            name,
+            dispatch: Dispatch::<T>(PhantomData),
+        }))
+    }
+
+    /// The name of the class.
+    pub fn name(&self) -> &EcoString {
+        &self.0.name
+    }
+
+    /// Construct an instance of the class.
+    pub fn construct(&self, ctx: &mut EvalContext, args: &mut Args) -> TypResult<Node> {
+        self.0.dispatch.construct(ctx, args)
+    }
+
+    /// Execute the class's set rule.
+    pub fn set(&self, styles: &mut Styles, args: &mut Args) -> TypResult<()> {
+        self.0.dispatch.set(styles, args)
+    }
+}
+
+impl Debug for Class {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.write_str("<class ")?;
+        f.write_str(&self.0.name)?;
+        f.write_char('>')
+    }
+}
+
+impl PartialEq for Class {
+    fn eq(&self, other: &Self) -> bool {
+        // We cast to thin pointers for comparison.
+        std::ptr::eq(
+            Rc::as_ptr(&self.0) as *const (),
+            Rc::as_ptr(&other.0) as *const (),
+        )
+    }
+}
+
+/// Construct an instance of a class.
+pub trait Construct {
+    /// Construct an instance of this class from the arguments.
+    ///
+    /// This is passed only the arguments that remain after execution of the
+    /// class's set rule.
+    fn construct(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Node>;
+}
+
+/// Set style properties of a class.
+pub trait Set {
+    /// Parse the arguments and insert style properties of this class into the
+    /// given style map.
+    fn set(styles: &mut Styles, args: &mut Args) -> TypResult<()>;
+}
+
+/// Zero-sized struct whose vtable contains the constructor and set rule of a
+/// class.
+struct Dispatch<T>(PhantomData<T>);
+
+trait Bounds {
+    fn construct(&self, ctx: &mut EvalContext, args: &mut Args) -> TypResult<Node>;
+    fn set(&self, styles: &mut Styles, args: &mut Args) -> TypResult<()>;
+}
+
+impl<T> Bounds for Dispatch<T>
+where
+    T: Construct + Set,
+{
+    fn construct(&self, ctx: &mut EvalContext, args: &mut Args) -> TypResult<Node> {
+        T::construct(ctx, args)
+    }
+
+    fn set(&self, styles: &mut Styles, args: &mut Args) -> TypResult<()> {
+        T::set(styles, args)
+    }
+}
diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index 6dcff900..ae330134 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -9,6 +9,7 @@ mod value;
 #[macro_use]
 mod styles;
 mod capture;
+mod class;
 mod function;
 mod node;
 mod ops;
@@ -16,6 +17,7 @@ mod scope;
 
 pub use array::*;
 pub use capture::*;
+pub use class::*;
 pub use dict::*;
 pub use function::*;
 pub use node::*;
@@ -54,7 +56,7 @@ pub fn eval(ctx: &mut Context, source: SourceId, markup: &Markup) -> TypResult<M
 pub struct Module {
     /// The top-level definitions that were bound in this module.
     pub scope: Scope,
-    /// The node defined by this module.
+    /// The module's layoutable contents.
     pub node: Node,
 }
 
@@ -288,6 +290,7 @@ impl Eval for Expr {
             Self::Unary(v) => v.eval(ctx),
             Self::Binary(v) => v.eval(ctx),
             Self::Let(v) => v.eval(ctx),
+            Self::Set(v) => v.eval(ctx),
             Self::If(v) => v.eval(ctx),
             Self::While(v) => v.eval(ctx),
             Self::For(v) => v.eval(ctx),
@@ -474,9 +477,17 @@ impl Eval for CallExpr {
                 Ok(value)
             }
 
+            Value::Class(class) => {
+                let mut styles = Styles::new();
+                class.set(&mut styles, &mut args)?;
+                let node = class.construct(ctx, &mut args)?;
+                args.finish()?;
+                Ok(Value::Node(node.styled(styles)))
+            }
+
             v => bail!(
                 self.callee().span(),
-                "expected function or collection, found {}",
+                "expected callable or collection, found {}",
                 v.type_name(),
             ),
         }
@@ -643,6 +654,19 @@ impl Eval for LetExpr {
     }
 }
 
+impl Eval for SetExpr {
+    type Output = Value;
+
+    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+        let class = self.class();
+        let class = class.eval(ctx)?.cast::<Class>().at(class.span())?;
+        let mut args = self.args().eval(ctx)?;
+        class.set(&mut ctx.styles, &mut args)?;
+        args.finish()?;
+        Ok(Value::None)
+    }
+}
+
 impl Eval for IfExpr {
     type Output = Value;
 
diff --git a/src/eval/node.rs b/src/eval/node.rs
index 5653beff..a04fe84b 100644
--- a/src/eval/node.rs
+++ b/src/eval/node.rs
@@ -36,6 +36,8 @@ pub enum Node {
     Inline(PackedNode),
     /// A block node.
     Block(PackedNode),
+    /// A page node.
+    Page(PackedNode),
     /// A sequence of nodes (which may themselves contain sequences).
     Sequence(Vec<(Self, Styles)>),
 }
@@ -214,6 +216,14 @@ impl Packer {
             Node::Block(block) => {
                 self.push_block(block.styled(styles));
             }
+            Node::Page(flow) => {
+                if self.top {
+                    self.pagebreak();
+                    self.pages.push(PageNode { child: flow, styles });
+                } else {
+                    self.push_block(flow.styled(styles));
+                }
+            }
             Node::Sequence(list) => {
                 // For a list of nodes, we apply the list's styles to each node
                 // individually.
diff --git a/src/eval/scope.rs b/src/eval/scope.rs
index ffe2d63e..5178c819 100644
--- a/src/eval/scope.rs
+++ b/src/eval/scope.rs
@@ -4,7 +4,7 @@ use std::fmt::{self, Debug, Formatter};
 use std::iter;
 use std::rc::Rc;
 
-use super::{Args, EvalContext, Function, Value};
+use super::{Args, Class, Construct, EvalContext, Function, Set, Value};
 use crate::diag::TypResult;
 use crate::util::EcoString;
 
@@ -88,15 +88,6 @@ impl Scope {
         self.values.insert(var.into(), Rc::new(cell));
     }
 
-    /// Define a constant function.
-    pub fn def_func<F>(&mut self, name: impl Into<EcoString>, f: F)
-    where
-        F: Fn(&mut EvalContext, &mut Args) -> TypResult<Value> + 'static,
-    {
-        let name = name.into();
-        self.def_const(name.clone(), Function::new(Some(name), f));
-    }
-
     /// Define a mutable variable with a value.
     pub fn def_mut(&mut self, var: impl Into<EcoString>, value: impl Into<Value>) {
         self.values.insert(var.into(), Rc::new(RefCell::new(value.into())));
@@ -107,6 +98,24 @@ impl Scope {
         self.values.insert(var.into(), slot);
     }
 
+    /// Define a constant function.
+    pub fn def_func<F>(&mut self, name: &str, f: F)
+    where
+        F: Fn(&mut EvalContext, &mut Args) -> TypResult<Value> + 'static,
+    {
+        let name = EcoString::from(name);
+        self.def_const(name.clone(), Function::new(Some(name), f));
+    }
+
+    /// Define a constant class.
+    pub fn def_class<T>(&mut self, name: &str)
+    where
+        T: Construct + Set + 'static,
+    {
+        let name = EcoString::from(name);
+        self.def_const(name.clone(), Class::new::<T>(name));
+    }
+
     /// Look up the value of a variable.
     pub fn get(&self, var: &str) -> Option<&Slot> {
         self.values.get(var)
diff --git a/src/eval/value.rs b/src/eval/value.rs
index 2cf82a26..0995ab75 100644
--- a/src/eval/value.rs
+++ b/src/eval/value.rs
@@ -4,7 +4,7 @@ use std::fmt::{self, Debug, Formatter};
 use std::hash::Hash;
 use std::rc::Rc;
 
-use super::{ops, Array, Dict, Function, Node};
+use super::{ops, Array, Class, Dict, Function, Node};
 use crate::diag::StrResult;
 use crate::geom::{Angle, Color, Fractional, Length, Linear, Relative, RgbaColor};
 use crate::layout::Layout;
@@ -46,6 +46,8 @@ pub enum Value {
     Node(Node),
     /// An executable function.
     Func(Function),
+    /// A class of nodes.
+    Class(Class),
     /// A dynamic value.
     Dyn(Dynamic),
 }
@@ -86,6 +88,7 @@ impl Value {
             Self::Dict(_) => Dict::TYPE_NAME,
             Self::Node(_) => Node::TYPE_NAME,
             Self::Func(_) => Function::TYPE_NAME,
+            Self::Class(_) => Class::TYPE_NAME,
             Self::Dyn(v) => v.type_name(),
         }
     }
@@ -148,6 +151,7 @@ impl Debug for Value {
             Self::Dict(v) => Debug::fmt(v, f),
             Self::Node(_) => f.pad("<template>"),
             Self::Func(v) => Debug::fmt(v, f),
+            Self::Class(v) => Debug::fmt(v, f),
             Self::Dyn(v) => Debug::fmt(v, f),
         }
     }
@@ -394,6 +398,7 @@ primitive! { Array: "array", Array }
 primitive! { Dict: "dictionary", Dict }
 primitive! { Node: "template", Node }
 primitive! { Function: "function", Func }
+primitive! { Class: "class", Class }
 
 impl Cast<Value> for Value {
     fn is(_: &Value) -> bool {
diff --git a/src/library/mod.rs b/src/library/mod.rs
index 9b6da6a9..1e2ee224 100644
--- a/src/library/mod.rs
+++ b/src/library/mod.rs
@@ -27,7 +27,9 @@ mod prelude {
     pub use std::rc::Rc;
 
     pub use crate::diag::{At, TypResult};
-    pub use crate::eval::{Args, EvalContext, Node, Property, Smart, Styles, Value};
+    pub use crate::eval::{
+        Args, Construct, EvalContext, Node, Property, Set, Smart, Styles, Value,
+    };
     pub use crate::frame::*;
     pub use crate::geom::*;
     pub use crate::layout::*;
@@ -60,22 +62,24 @@ use crate::geom::*;
 pub fn new() -> Scope {
     let mut std = Scope::new();
 
-    // Text.
-    std.def_func("font", font);
-    std.def_func("par", par);
-    std.def_func("parbreak", parbreak);
+    // Classes.
+    std.def_class::<PageNode>("page");
+    std.def_class::<ParNode>("par");
+    std.def_class::<TextNode>("text");
+
+    // Text functions.
     std.def_func("strike", strike);
     std.def_func("underline", underline);
     std.def_func("overline", overline);
     std.def_func("link", link);
 
-    // Layout.
-    std.def_func("page", page);
-    std.def_func("pagebreak", pagebreak);
+    // Layout functions.
     std.def_func("h", h);
     std.def_func("v", v);
     std.def_func("box", box_);
     std.def_func("block", block);
+    std.def_func("pagebreak", pagebreak);
+    std.def_func("parbreak", parbreak);
     std.def_func("stack", stack);
     std.def_func("grid", grid);
     std.def_func("pad", pad);
@@ -85,14 +89,14 @@ pub fn new() -> Scope {
     std.def_func("scale", scale);
     std.def_func("rotate", rotate);
 
-    // Elements.
+    // Element functions.
     std.def_func("image", image);
     std.def_func("rect", rect);
     std.def_func("square", square);
     std.def_func("ellipse", ellipse);
     std.def_func("circle", circle);
 
-    // Utility.
+    // Utility functions.
     std.def_func("assert", assert);
     std.def_func("type", type_);
     std.def_func("repr", repr);
@@ -110,14 +114,14 @@ pub fn new() -> Scope {
     std.def_func("len", len);
     std.def_func("sorted", sorted);
 
-    // Colors.
+    // Predefined colors.
     std.def_const("white", RgbaColor::WHITE);
     std.def_const("black", RgbaColor::BLACK);
     std.def_const("eastern", RgbaColor::new(0x23, 0x9D, 0xAD, 0xFF));
     std.def_const("conifer", RgbaColor::new(0x9f, 0xEB, 0x52, 0xFF));
     std.def_const("forest", RgbaColor::new(0x43, 0xA1, 0x27, 0xFF));
 
-    // Arbitrary constants.
+    // Other constants.
     std.def_const("ltr", Dir::LTR);
     std.def_const("rtl", Dir::RTL);
     std.def_const("ttb", Dir::TTB);
diff --git a/src/library/page.rs b/src/library/page.rs
index 4a4fab03..0b0cc2d9 100644
--- a/src/library/page.rs
+++ b/src/library/page.rs
@@ -6,53 +6,6 @@ use std::str::FromStr;
 use super::prelude::*;
 use super::PadNode;
 
-/// `page`: Configure pages.
-pub fn page(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    castable! {
-        Paper,
-        Expected: "string",
-        Value::Str(string) => Paper::from_str(&string).map_err(|e| e.to_string())?,
-    }
-
-    let body: Option<Node> = args.find();
-
-    let mut map = Styles::new();
-    let styles = match body {
-        Some(_) => &mut map,
-        None => &mut ctx.styles,
-    };
-
-    if let Some(paper) = args.named::<Paper>("paper")?.or_else(|| args.find()) {
-        styles.set(PageNode::CLASS, paper.class());
-        styles.set(PageNode::WIDTH, Smart::Custom(paper.width()));
-        styles.set(PageNode::HEIGHT, Smart::Custom(paper.height()));
-    }
-
-    if let Some(width) = args.named("width")? {
-        styles.set(PageNode::CLASS, PaperClass::Custom);
-        styles.set(PageNode::WIDTH, width);
-    }
-
-    if let Some(height) = args.named("height")? {
-        styles.set(PageNode::CLASS, PaperClass::Custom);
-        styles.set(PageNode::HEIGHT, height);
-    }
-
-    let margins = args.named("margins")?;
-
-    set!(styles, PageNode::FLIPPED => args.named("flipped")?);
-    set!(styles, PageNode::LEFT => args.named("left")?.or(margins));
-    set!(styles, PageNode::TOP => args.named("top")?.or(margins));
-    set!(styles, PageNode::RIGHT => args.named("right")?.or(margins));
-    set!(styles, PageNode::BOTTOM => args.named("bottom")?.or(margins));
-    set!(styles, PageNode::FILL => args.named("fill")?);
-
-    Ok(match body {
-        Some(body) => Value::block(body.into_block().styled(map)),
-        None => Value::None,
-    })
-}
-
 /// `pagebreak`: Start a new page.
 pub fn pagebreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
     Ok(Value::Node(Node::Pagebreak))
@@ -90,6 +43,45 @@ properties! {
     FILL: Option<Paint> = None,
 }
 
+impl Construct for PageNode {
+    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Node> {
+        // TODO(set): Make sure it's really a page so that it doesn't merge
+        // with adjacent pages.
+        Ok(Node::Page(args.expect::<Node>("body")?.into_block()))
+    }
+}
+
+impl Set for PageNode {
+    fn set(styles: &mut Styles, args: &mut Args) -> TypResult<()> {
+        if let Some(paper) = args.named::<Paper>("paper")?.or_else(|| args.find()) {
+            styles.set(PageNode::CLASS, paper.class());
+            styles.set(PageNode::WIDTH, Smart::Custom(paper.width()));
+            styles.set(PageNode::HEIGHT, Smart::Custom(paper.height()));
+        }
+
+        if let Some(width) = args.named("width")? {
+            styles.set(PageNode::CLASS, PaperClass::Custom);
+            styles.set(PageNode::WIDTH, width);
+        }
+
+        if let Some(height) = args.named("height")? {
+            styles.set(PageNode::CLASS, PaperClass::Custom);
+            styles.set(PageNode::HEIGHT, height);
+        }
+
+        let margins = args.named("margins")?;
+
+        set!(styles, PageNode::FLIPPED => args.named("flipped")?);
+        set!(styles, PageNode::LEFT => args.named("left")?.or(margins));
+        set!(styles, PageNode::TOP => args.named("top")?.or(margins));
+        set!(styles, PageNode::RIGHT => args.named("right")?.or(margins));
+        set!(styles, PageNode::BOTTOM => args.named("bottom")?.or(margins));
+        set!(styles, PageNode::FILL => args.named("fill")?);
+
+        Ok(())
+    }
+}
+
 impl PageNode {
     /// Layout the page run into a sequence of frames, one per page.
     pub fn layout(&self, ctx: &mut LayoutContext) -> Vec<Rc<Frame>> {
@@ -182,6 +174,12 @@ impl Default for Paper {
     }
 }
 
+castable! {
+    Paper,
+    Expected: "string",
+    Value::Str(string) => Paper::from_str(&string).map_err(|e| e.to_string())?,
+}
+
 /// Defines default margins for a class of related papers.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub enum PaperClass {
diff --git a/src/library/par.rs b/src/library/par.rs
index 6ea960bf..d63c2315 100644
--- a/src/library/par.rs
+++ b/src/library/par.rs
@@ -9,46 +9,6 @@ use super::prelude::*;
 use super::{shape, ShapedText, SpacingKind, SpacingNode, TextNode};
 use crate::util::{EcoString, RangeExt, RcExt, SliceExt};
 
-/// `par`: Configure paragraphs.
-pub fn par(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    let spacing = args.named("spacing")?;
-    let leading = args.named("leading")?;
-
-    let mut dir =
-        args.named("lang")?
-            .map(|iso: EcoString| match iso.to_lowercase().as_str() {
-                "ar" | "he" | "fa" | "ur" | "ps" | "yi" => Dir::RTL,
-                "en" | "fr" | "de" => Dir::LTR,
-                _ => Dir::LTR,
-            });
-
-    if let Some(Spanned { v, span }) = args.named::<Spanned<Dir>>("dir")? {
-        if v.axis() != SpecAxis::Horizontal {
-            bail!(span, "must be horizontal");
-        }
-        dir = Some(v);
-    }
-
-    let mut align = None;
-    if let Some(Spanned { v, span }) = args.named::<Spanned<Align>>("align")? {
-        if v.axis() != SpecAxis::Horizontal {
-            bail!(span, "must be horizontal");
-        }
-        align = Some(v);
-    }
-
-    if let (Some(dir), None) = (dir, align) {
-        align = Some(if dir == Dir::LTR { Align::Left } else { Align::Right });
-    }
-
-    set!(ctx.styles, ParNode::DIR => dir);
-    set!(ctx.styles, ParNode::ALIGN => align);
-    set!(ctx.styles, ParNode::LEADING => leading);
-    set!(ctx.styles, ParNode::SPACING => spacing);
-
-    Ok(Value::None)
-}
-
 /// `parbreak`: Start a new paragraph.
 pub fn parbreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
     Ok(Value::Node(Node::Parbreak))
@@ -71,6 +31,54 @@ properties! {
     SPACING: Linear = Relative::new(1.2).into(),
 }
 
+impl Construct for ParNode {
+    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Node> {
+        // Lift to a block so that it doesn't merge with adjacent stuff.
+        Ok(Node::Block(args.expect::<Node>("body")?.into_block()))
+    }
+}
+
+impl Set for ParNode {
+    fn set(styles: &mut Styles, args: &mut Args) -> TypResult<()> {
+        let spacing = args.named("spacing")?;
+        let leading = args.named("leading")?;
+
+        let mut dir =
+            args.named("lang")?
+                .map(|iso: EcoString| match iso.to_lowercase().as_str() {
+                    "ar" | "he" | "fa" | "ur" | "ps" | "yi" => Dir::RTL,
+                    "en" | "fr" | "de" => Dir::LTR,
+                    _ => Dir::LTR,
+                });
+
+        if let Some(Spanned { v, span }) = args.named::<Spanned<Dir>>("dir")? {
+            if v.axis() != SpecAxis::Horizontal {
+                bail!(span, "must be horizontal");
+            }
+            dir = Some(v);
+        }
+
+        let mut align = None;
+        if let Some(Spanned { v, span }) = args.named::<Spanned<Align>>("align")? {
+            if v.axis() != SpecAxis::Horizontal {
+                bail!(span, "must be horizontal");
+            }
+            align = Some(v);
+        }
+
+        if let (Some(dir), None) = (dir, align) {
+            align = Some(if dir == Dir::LTR { Align::Left } else { Align::Right });
+        }
+
+        set!(styles, ParNode::DIR => dir);
+        set!(styles, ParNode::ALIGN => align);
+        set!(styles, ParNode::LEADING => leading);
+        set!(styles, ParNode::SPACING => spacing);
+
+        Ok(())
+    }
+}
+
 impl Layout for ParNode {
     fn layout(
         &self,
diff --git a/src/library/text.rs b/src/library/text.rs
index 4ab378c2..4baf4bc5 100644
--- a/src/library/text.rs
+++ b/src/library/text.rs
@@ -15,54 +15,6 @@ use crate::font::{
 use crate::geom::{Dir, Em, Length, Point, Size};
 use crate::util::{EcoString, SliceExt};
 
-/// `font`: Configure the font.
-pub fn font(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    let body = args.find::<Node>();
-
-    let mut map = Styles::new();
-    let styles = match body {
-        Some(_) => &mut map,
-        None => &mut ctx.styles,
-    };
-
-    let list = args.named("family")?.or_else(|| {
-        let families: Vec<_> = args.all().collect();
-        (!families.is_empty()).then(|| families)
-    });
-
-    set!(styles, TextNode::FAMILY_LIST => list);
-    set!(styles, TextNode::SERIF_LIST => args.named("serif")?);
-    set!(styles, TextNode::SANS_SERIF_LIST => args.named("sans-serif")?);
-    set!(styles, TextNode::MONOSPACE_LIST => args.named("monospace")?);
-    set!(styles, TextNode::FALLBACK => args.named("fallback")?);
-    set!(styles, TextNode::STYLE => args.named("style")?);
-    set!(styles, TextNode::WEIGHT => args.named("weight")?);
-    set!(styles, TextNode::STRETCH => args.named("stretch")?);
-    set!(styles, TextNode::FILL => args.named("fill")?.or_else(|| args.find()));
-    set!(styles, TextNode::SIZE => args.named("size")?.or_else(|| args.find()));
-    set!(styles, TextNode::TRACKING => args.named("tracking")?.map(Em::new));
-    set!(styles, TextNode::TOP_EDGE => args.named("top-edge")?);
-    set!(styles, TextNode::BOTTOM_EDGE => args.named("bottom-edge")?);
-    set!(styles, TextNode::KERNING => args.named("kerning")?);
-    set!(styles, TextNode::SMALLCAPS => args.named("smallcaps")?);
-    set!(styles, TextNode::ALTERNATES => args.named("alternates")?);
-    set!(styles, TextNode::STYLISTIC_SET => args.named("stylistic-set")?);
-    set!(styles, TextNode::LIGATURES => args.named("ligatures")?);
-    set!(styles, TextNode::DISCRETIONARY_LIGATURES => args.named("discretionary-ligatures")?);
-    set!(styles, TextNode::HISTORICAL_LIGATURES => args.named("historical-ligatures")?);
-    set!(styles, TextNode::NUMBER_TYPE => args.named("number-type")?);
-    set!(styles, TextNode::NUMBER_WIDTH => args.named("number-width")?);
-    set!(styles, TextNode::NUMBER_POSITION => args.named("number-position")?);
-    set!(styles, TextNode::SLASHED_ZERO => args.named("slashed-zero")?);
-    set!(styles, TextNode::FRACTIONS => args.named("fractions")?);
-    set!(styles, TextNode::FEATURES => args.named("features")?);
-
-    Ok(match body {
-        Some(body) => Value::Node(body.styled(map)),
-        None => Value::None,
-    })
-}
-
 /// `strike`: Typeset striken-through text.
 pub fn strike(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     line_impl(args, LineKind::Strikethrough)
@@ -172,6 +124,53 @@ properties! {
     FEATURES: Vec<(Tag, u32)> = vec![],
 }
 
+impl Construct for TextNode {
+    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Node> {
+        // We don't need to do anything more here because the whole point of the
+        // text constructor is to apply the styles and that happens
+        // automatically during class construction.
+        args.expect::<Node>("body")
+    }
+}
+
+impl Set for TextNode {
+    fn set(styles: &mut Styles, args: &mut Args) -> TypResult<()> {
+        let list = args.named("family")?.or_else(|| {
+            let families: Vec<_> = args.all().collect();
+            (!families.is_empty()).then(|| families)
+        });
+
+        set!(styles, TextNode::FAMILY_LIST => list);
+        set!(styles, TextNode::SERIF_LIST => args.named("serif")?);
+        set!(styles, TextNode::SANS_SERIF_LIST => args.named("sans-serif")?);
+        set!(styles, TextNode::MONOSPACE_LIST => args.named("monospace")?);
+        set!(styles, TextNode::FALLBACK => args.named("fallback")?);
+        set!(styles, TextNode::STYLE => args.named("style")?);
+        set!(styles, TextNode::WEIGHT => args.named("weight")?);
+        set!(styles, TextNode::STRETCH => args.named("stretch")?);
+        set!(styles, TextNode::FILL => args.named("fill")?.or_else(|| args.find()));
+        set!(styles, TextNode::SIZE => args.named("size")?.or_else(|| args.find()));
+        set!(styles, TextNode::TRACKING => args.named("tracking")?.map(Em::new));
+        set!(styles, TextNode::TOP_EDGE => args.named("top-edge")?);
+        set!(styles, TextNode::BOTTOM_EDGE => args.named("bottom-edge")?);
+        set!(styles, TextNode::KERNING => args.named("kerning")?);
+        set!(styles, TextNode::SMALLCAPS => args.named("smallcaps")?);
+        set!(styles, TextNode::ALTERNATES => args.named("alternates")?);
+        set!(styles, TextNode::STYLISTIC_SET => args.named("stylistic-set")?);
+        set!(styles, TextNode::LIGATURES => args.named("ligatures")?);
+        set!(styles, TextNode::DISCRETIONARY_LIGATURES => args.named("discretionary-ligatures")?);
+        set!(styles, TextNode::HISTORICAL_LIGATURES => args.named("historical-ligatures")?);
+        set!(styles, TextNode::NUMBER_TYPE => args.named("number-type")?);
+        set!(styles, TextNode::NUMBER_WIDTH => args.named("number-width")?);
+        set!(styles, TextNode::NUMBER_POSITION => args.named("number-position")?);
+        set!(styles, TextNode::SLASHED_ZERO => args.named("slashed-zero")?);
+        set!(styles, TextNode::FRACTIONS => args.named("fractions")?);
+        set!(styles, TextNode::FEATURES => args.named("features")?);
+
+        Ok(())
+    }
+}
+
 impl Debug for TextNode {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         if f.alternate() {
diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index dbec0a5e..0a2f73f5 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -110,12 +110,13 @@ fn markup_node(p: &mut Parser, at_start: &mut bool) {
         // Hashtag + keyword / identifier.
         NodeKind::Ident(_)
         | NodeKind::Let
+        | NodeKind::Set
         | NodeKind::If
         | NodeKind::While
         | NodeKind::For
         | NodeKind::Import
         | NodeKind::Include => {
-            let stmt = matches!(token, NodeKind::Let | NodeKind::Import);
+            let stmt = matches!(token, NodeKind::Let | NodeKind::Set | NodeKind::Import);
             let group = if stmt { Group::Stmt } else { Group::Expr };
 
             p.start_group(group);
@@ -265,6 +266,7 @@ fn primary(p: &mut Parser, atomic: bool) -> ParseResult {
 
         // Keywords.
         Some(NodeKind::Let) => let_expr(p),
+        Some(NodeKind::Set) => set_expr(p),
         Some(NodeKind::If) => if_expr(p),
         Some(NodeKind::While) => while_expr(p),
         Some(NodeKind::For) => for_expr(p),
@@ -507,45 +509,40 @@ fn block(p: &mut Parser) {
 
 /// Parse a function call.
 fn call(p: &mut Parser, callee: Marker) -> ParseResult {
-    callee.perform(p, NodeKind::Call, |p| match p.peek_direct() {
-        Some(NodeKind::LeftParen | NodeKind::LeftBracket) => {
-            args(p, true);
-            Ok(())
-        }
-        _ => {
-            p.expected_at("argument list");
-            Err(())
-        }
-    })
+    callee.perform(p, NodeKind::Call, |p| args(p, true, true))
 }
 
 /// Parse the arguments to a function call.
-fn args(p: &mut Parser, allow_template: bool) {
+fn args(p: &mut Parser, direct: bool, brackets: bool) -> ParseResult {
+    match if direct { p.peek_direct() } else { p.peek() } {
+        Some(NodeKind::LeftParen) => {}
+        Some(NodeKind::LeftBracket) if brackets => {}
+        _ => {
+            p.expected("argument list");
+            return Err(());
+        }
+    }
+
     p.perform(NodeKind::CallArgs, |p| {
-        if !allow_template || p.peek_direct() == Some(&NodeKind::LeftParen) {
+        if p.at(&NodeKind::LeftParen) {
             p.start_group(Group::Paren);
             collection(p);
             p.end_group();
         }
 
-        while allow_template && p.peek_direct() == Some(&NodeKind::LeftBracket) {
+        while brackets && p.peek_direct() == Some(&NodeKind::LeftBracket) {
             template(p);
         }
-    })
+    });
+
+    Ok(())
 }
 
 /// Parse a with expression.
 fn with_expr(p: &mut Parser, marker: Marker) -> ParseResult {
     marker.perform(p, NodeKind::WithExpr, |p| {
         p.eat_assert(&NodeKind::With);
-
-        if p.at(&NodeKind::LeftParen) {
-            args(p, false);
-            Ok(())
-        } else {
-            p.expected("argument list");
-            Err(())
-        }
+        args(p, false, false)
     })
 }
 
@@ -587,6 +584,15 @@ fn let_expr(p: &mut Parser) -> ParseResult {
     })
 }
 
+/// Parse a set expression.
+fn set_expr(p: &mut Parser) -> ParseResult {
+    p.perform(NodeKind::SetExpr, |p| {
+        p.eat_assert(&NodeKind::Set);
+        ident(p)?;
+        args(p, true, false)
+    })
+}
+
 /// Parse an if expresion.
 fn if_expr(p: &mut Parser) -> ParseResult {
     p.perform(NodeKind::IfExpr, |p| {
@@ -612,8 +618,7 @@ fn while_expr(p: &mut Parser) -> ParseResult {
     p.perform(NodeKind::WhileExpr, |p| {
         p.eat_assert(&NodeKind::While);
         expr(p)?;
-        body(p)?;
-        Ok(())
+        body(p)
     })
 }
 
@@ -624,8 +629,7 @@ fn for_expr(p: &mut Parser) -> ParseResult {
         for_pattern(p)?;
         p.eat_expect(&NodeKind::In)?;
         expr(p)?;
-        body(p)?;
-        Ok(())
+        body(p)
     })
 }
 
@@ -664,9 +668,7 @@ fn import_expr(p: &mut Parser) -> ParseResult {
         };
 
         p.eat_expect(&NodeKind::From)?;
-        expr(p)?;
-
-        Ok(())
+        expr(p)
     })
 }
 
@@ -674,8 +676,7 @@ fn import_expr(p: &mut Parser) -> ParseResult {
 fn include_expr(p: &mut Parser) -> ParseResult {
     p.perform(NodeKind::IncludeExpr, |p| {
         p.eat_assert(&NodeKind::Include);
-        expr(p)?;
-        Ok(())
+        expr(p)
     })
 }
 
diff --git a/src/parse/parser.rs b/src/parse/parser.rs
index 6598b1f2..503158a9 100644
--- a/src/parse/parser.rs
+++ b/src/parse/parser.rs
@@ -125,6 +125,7 @@ impl<'s> Parser<'s> {
     }
 
     /// Eat, debug-asserting that the token is the given one.
+    #[track_caller]
     pub fn eat_assert(&mut self, t: &NodeKind) {
         debug_assert_eq!(self.peek(), Some(t));
         self.eat();
@@ -199,6 +200,7 @@ impl<'s> Parser<'s> {
     /// to `end_group`.
     ///
     /// This panics if the current token does not start the given group.
+    #[track_caller]
     pub fn start_group(&mut self, kind: Group) {
         self.groups.push(GroupEntry { kind, prev_mode: self.tokens.mode() });
         self.tokens.set_mode(match kind {
@@ -220,6 +222,7 @@ impl<'s> Parser<'s> {
     /// End the parsing of a group.
     ///
     /// This panics if no group was started.
+    #[track_caller]
     pub fn end_group(&mut self) {
         let group_mode = self.tokens.mode();
         let group = self.groups.pop().expect("no started group");
diff --git a/src/parse/tokens.rs b/src/parse/tokens.rs
index 07a6fe12..27ec046d 100644
--- a/src/parse/tokens.rs
+++ b/src/parse/tokens.rs
@@ -527,6 +527,7 @@ fn keyword(ident: &str) -> Option<NodeKind> {
         "or" => NodeKind::Or,
         "with" => NodeKind::With,
         "let" => NodeKind::Let,
+        "set" => NodeKind::Set,
         "if" => NodeKind::If,
         "else" => NodeKind::Else,
         "for" => NodeKind::For,
diff --git a/src/source.rs b/src/source.rs
index 509b0a76..5fd85ed9 100644
--- a/src/source.rs
+++ b/src/source.rs
@@ -149,6 +149,11 @@ impl SourceFile {
         Self::new(SourceId(0), Path::new(""), src.into())
     }
 
+    /// The root node of the untyped green tree.
+    pub fn root(&self) -> &Rc<GreenNode> {
+        &self.root
+    }
+
     /// The file's abstract syntax tree.
     pub fn ast(&self) -> TypResult<Markup> {
         let red = RedNode::from_root(self.root.clone(), self.id);
diff --git a/src/syntax/ast.rs b/src/syntax/ast.rs
index 8df25f59..9190953f 100644
--- a/src/syntax/ast.rs
+++ b/src/syntax/ast.rs
@@ -211,6 +211,8 @@ pub enum Expr {
     With(WithExpr),
     /// A let expression: `let x = 1`.
     Let(LetExpr),
+    /// A set expression: `set text(...)`.
+    Set(SetExpr),
     /// An if-else expression: `if x { y } else { z }`.
     If(IfExpr),
     /// A while loop expression: `while x { y }`.
@@ -238,6 +240,7 @@ impl TypedNode for Expr {
             NodeKind::Closure => node.cast().map(Self::Closure),
             NodeKind::WithExpr => node.cast().map(Self::With),
             NodeKind::LetExpr => node.cast().map(Self::Let),
+            NodeKind::SetExpr => node.cast().map(Self::Set),
             NodeKind::IfExpr => node.cast().map(Self::If),
             NodeKind::WhileExpr => node.cast().map(Self::While),
             NodeKind::ForExpr => node.cast().map(Self::For),
@@ -262,6 +265,7 @@ impl TypedNode for Expr {
             Self::Closure(v) => v.as_red(),
             Self::With(v) => v.as_red(),
             Self::Let(v) => v.as_red(),
+            Self::Set(v) => v.as_red(),
             Self::If(v) => v.as_red(),
             Self::While(v) => v.as_red(),
             Self::For(v) => v.as_red(),
@@ -838,6 +842,25 @@ impl LetExpr {
 }
 
 node! {
+    /// A set expression: `set text(...)`.
+    SetExpr
+}
+
+impl SetExpr {
+    /// The class to set style properties for.
+    pub fn class(&self) -> Ident {
+        self.0.cast_first_child().expect("set expression is missing class")
+    }
+
+    /// The style properties to set.
+    pub fn args(&self) -> CallArgs {
+        self.0
+            .cast_first_child()
+            .expect("set expression is missing argument list")
+    }
+}
+
+node! {
     /// An import expression: `import a, b, c from "utils.typ"`.
     ImportExpr
 }
diff --git a/src/syntax/highlight.rs b/src/syntax/highlight.rs
index 22e6cf50..85fbef12 100644
--- a/src/syntax/highlight.rs
+++ b/src/syntax/highlight.rs
@@ -96,22 +96,23 @@ impl Category {
             NodeKind::EnDash => Some(Category::Shortcut),
             NodeKind::EmDash => Some(Category::Shortcut),
             NodeKind::Escape(_) => Some(Category::Escape),
+            NodeKind::Not => Some(Category::Keyword),
+            NodeKind::And => Some(Category::Keyword),
+            NodeKind::Or => Some(Category::Keyword),
+            NodeKind::With => Some(Category::Keyword),
             NodeKind::Let => Some(Category::Keyword),
+            NodeKind::Set => Some(Category::Keyword),
             NodeKind::If => Some(Category::Keyword),
             NodeKind::Else => Some(Category::Keyword),
+            NodeKind::While => Some(Category::Keyword),
             NodeKind::For => Some(Category::Keyword),
             NodeKind::In => Some(Category::Keyword),
-            NodeKind::While => Some(Category::Keyword),
             NodeKind::Break => Some(Category::Keyword),
             NodeKind::Continue => Some(Category::Keyword),
             NodeKind::Return => Some(Category::Keyword),
             NodeKind::Import => Some(Category::Keyword),
-            NodeKind::Include => Some(Category::Keyword),
             NodeKind::From => Some(Category::Keyword),
-            NodeKind::Not => Some(Category::Keyword),
-            NodeKind::And => Some(Category::Keyword),
-            NodeKind::Or => Some(Category::Keyword),
-            NodeKind::With => Some(Category::Keyword),
+            NodeKind::Include => Some(Category::Keyword),
             NodeKind::Plus => Some(Category::Operator),
             NodeKind::Star => Some(Category::Operator),
             NodeKind::Slash => Some(Category::Operator),
@@ -139,6 +140,7 @@ impl Category {
                     Some(Category::Function)
                 }
                 NodeKind::WithExpr => Some(Category::Function),
+                NodeKind::SetExpr => Some(Category::Function),
                 NodeKind::Call => Some(Category::Function),
                 _ => Some(Category::Variable),
             },
@@ -161,21 +163,22 @@ impl Category {
             NodeKind::Array => None,
             NodeKind::Dict => None,
             NodeKind::Named => None,
+            NodeKind::Template => None,
             NodeKind::Group => None,
+            NodeKind::Block => None,
             NodeKind::Unary => None,
             NodeKind::Binary => None,
             NodeKind::Call => None,
             NodeKind::CallArgs => None,
+            NodeKind::Spread => None,
             NodeKind::Closure => None,
             NodeKind::ClosureParams => None,
-            NodeKind::Spread => None,
-            NodeKind::Template => None,
-            NodeKind::Block => None,
-            NodeKind::ForExpr => None,
-            NodeKind::WhileExpr => None,
-            NodeKind::IfExpr => None,
-            NodeKind::LetExpr => None,
             NodeKind::WithExpr => None,
+            NodeKind::LetExpr => None,
+            NodeKind::SetExpr => None,
+            NodeKind::IfExpr => None,
+            NodeKind::WhileExpr => None,
+            NodeKind::ForExpr => None,
             NodeKind::ForPattern => None,
             NodeKind::ImportExpr => None,
             NodeKind::ImportItems => None,
diff --git a/src/syntax/mod.rs b/src/syntax/mod.rs
index e9011a4d..b9b00487 100644
--- a/src/syntax/mod.rs
+++ b/src/syntax/mod.rs
@@ -83,19 +83,15 @@ impl Default for Green {
 
 impl Debug for Green {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{:?}: {}", self.kind(), self.len())?;
-        if let Self::Node(n) = self {
-            if !n.children.is_empty() {
-                f.write_str(" ")?;
-                f.debug_list().entries(&n.children).finish()?;
-            }
+        match self {
+            Self::Node(node) => node.fmt(f),
+            Self::Token(token) => token.fmt(f),
         }
-        Ok(())
     }
 }
 
 /// An inner node in the untyped green tree.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Clone, PartialEq)]
 pub struct GreenNode {
     /// Node metadata.
     data: GreenData,
@@ -145,8 +141,19 @@ impl From<Rc<GreenNode>> for Green {
     }
 }
 
+impl Debug for GreenNode {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        self.data.fmt(f)?;
+        if !self.children.is_empty() {
+            f.write_str(" ")?;
+            f.debug_list().entries(&self.children).finish()?;
+        }
+        Ok(())
+    }
+}
+
 /// Data shared between inner and leaf nodes.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Clone, PartialEq)]
 pub struct GreenData {
     /// What kind of node this is (each kind would have its own struct in a
     /// strongly typed AST).
@@ -178,6 +185,12 @@ impl From<GreenData> for Green {
     }
 }
 
+impl Debug for GreenData {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "{:?}: {}", self.kind, self.len())
+    }
+}
+
 /// A owned wrapper for a green node with span information.
 ///
 /// Owned variant of [`RedRef`]. Can be [cast](Self::cast) to an AST node.
@@ -465,6 +478,8 @@ pub enum NodeKind {
     Auto,
     /// The `let` keyword.
     Let,
+    /// The `set` keyword.
+    Set,
     /// The `if` keyword.
     If,
     /// The `else` keyword.
@@ -552,8 +567,12 @@ pub enum NodeKind {
     Dict,
     /// A named pair: `thickness: 3pt`.
     Named,
+    /// A template expression: `[*Hi* there!]`.
+    Template,
     /// A grouped expression: `(1 + 2)`.
     Group,
+    /// A block expression: `{ let x = 1; x + 2 }`.
+    Block,
     /// A unary operation: `-x`.
     Unary,
     /// A binary operation: `a + b`.
@@ -562,39 +581,37 @@ pub enum NodeKind {
     Call,
     /// A function call's argument list: `(x, y)`.
     CallArgs,
+    /// Spreaded arguments or a parameter sink: `..x`.
+    Spread,
     /// A closure expression: `(x, y) => z`.
     Closure,
     /// A closure's parameters: `(x, y)`.
     ClosureParams,
-    /// A parameter sink: `..x`.
-    Spread,
-    /// A template expression: `[*Hi* there!]`.
-    Template,
-    /// A block expression: `{ let x = 1; x + 2 }`.
-    Block,
-    /// A for loop expression: `for x in y { ... }`.
-    ForExpr,
-    /// A while loop expression: `while x { ... }`.
-    WhileExpr,
-    /// An if expression: `if x { ... }`.
-    IfExpr,
+    /// A with expression: `f with (x, y: 1)`.
+    WithExpr,
     /// A let expression: `let x = 1`.
     LetExpr,
-    /// The `with` expression: `with (1)`.
-    WithExpr,
+    /// A set expression: `set text(...)`.
+    SetExpr,
+    /// An if-else expression: `if x { y } else { z }`.
+    IfExpr,
+    /// A while loop expression: `while x { ... }`.
+    WhileExpr,
+    /// A for loop expression: `for x in y { ... }`.
+    ForExpr,
     /// A for loop's destructuring pattern: `x` or `x, y`.
     ForPattern,
-    /// The import expression: `import x from "foo.typ"`.
+    /// An import expression: `import a, b, c from "utils.typ"`.
     ImportExpr,
     /// Items to import: `a, b, c`.
     ImportItems,
-    /// The include expression: `include "foo.typ"`.
+    /// An include expression: `include "chapter1.typ"`.
     IncludeExpr,
-    /// Two slashes followed by inner contents, terminated with a newline:
-    /// `//<str>\n`.
+    /// A line comment, two slashes followed by inner contents, terminated with
+    /// a newline: `//<str>\n`.
     LineComment,
-    /// A slash and a star followed by inner contents,  terminated with a star
-    /// and a slash: `/*<str>*/`.
+    /// A block comment, a slash and a star followed by inner contents,
+    /// terminated with a star and a slash: `/*<str>*/`.
     ///
     /// The comment can contain nested block comments.
     BlockComment,
@@ -616,11 +633,6 @@ pub enum ErrorPos {
 }
 
 impl NodeKind {
-    /// Whether this is some kind of parenthesis.
-    pub fn is_paren(&self) -> bool {
-        matches!(self, Self::LeftParen | Self::RightParen)
-    }
-
     /// Whether this is some kind of bracket.
     pub fn is_bracket(&self) -> bool {
         matches!(self, Self::LeftBracket | Self::RightBracket)
@@ -631,6 +643,11 @@ impl NodeKind {
         matches!(self, Self::LeftBrace | Self::RightBrace)
     }
 
+    /// Whether this is some kind of parenthesis.
+    pub fn is_paren(&self) -> bool {
+        matches!(self, Self::LeftParen | Self::RightParen)
+    }
+
     /// Whether this is some kind of error.
     pub fn is_error(&self) -> bool {
         matches!(self, NodeKind::Error(_, _) | NodeKind::Unknown(_))
@@ -672,6 +689,7 @@ impl NodeKind {
             Self::None => "`none`",
             Self::Auto => "`auto`",
             Self::Let => "keyword `let`",
+            Self::Set => "keyword `set`",
             Self::If => "keyword `if`",
             Self::Else => "keyword `else`",
             Self::For => "keyword `for`",
@@ -712,21 +730,22 @@ impl NodeKind {
             Self::Array => "array",
             Self::Dict => "dictionary",
             Self::Named => "named argument",
+            Self::Template => "template",
             Self::Group => "group",
+            Self::Block => "block",
             Self::Unary => "unary expression",
             Self::Binary => "binary expression",
             Self::Call => "call",
             Self::CallArgs => "call arguments",
+            Self::Spread => "parameter sink",
             Self::Closure => "closure",
             Self::ClosureParams => "closure parameters",
-            Self::Spread => "parameter sink",
-            Self::Template => "template",
-            Self::Block => "block",
-            Self::ForExpr => "for-loop expression",
-            Self::WhileExpr => "while-loop expression",
-            Self::IfExpr => "`if` expression",
-            Self::LetExpr => "`let` expression",
             Self::WithExpr => "`with` expression",
+            Self::LetExpr => "`let` expression",
+            Self::SetExpr => "`set` expression",
+            Self::IfExpr => "`if` expression",
+            Self::WhileExpr => "while-loop expression",
+            Self::ForExpr => "for-loop expression",
             Self::ForPattern => "for-loop destructuring pattern",
             Self::ImportExpr => "`import` expression",
             Self::ImportItems => "import items",
diff --git a/src/syntax/pretty.rs b/src/syntax/pretty.rs
index c453fb56..62ecb8cd 100644
--- a/src/syntax/pretty.rs
+++ b/src/syntax/pretty.rs
@@ -225,6 +225,7 @@ impl Pretty for Expr {
             Self::Closure(v) => v.pretty(p),
             Self::With(v) => v.pretty(p),
             Self::Let(v) => v.pretty(p),
+            Self::Set(v) => v.pretty(p),
             Self::If(v) => v.pretty(p),
             Self::While(v) => v.pretty(p),
             Self::For(v) => v.pretty(p),
@@ -444,6 +445,16 @@ impl Pretty for LetExpr {
     }
 }
 
+impl Pretty for SetExpr {
+    fn pretty(&self, p: &mut Printer) {
+        p.push_str("set ");
+        self.class().pretty(p);
+        p.push_str("(");
+        self.args().pretty(p);
+        p.push(')');
+    }
+}
+
 impl Pretty for IfExpr {
     fn pretty(&self, p: &mut Printer) {
         p.push_str("if ");
@@ -639,6 +650,7 @@ mod tests {
         // Control flow.
         roundtrip("#let x = 1 + 2");
         roundtrip("#let f(x) = y");
+        roundtrip("#set text(size: 12pt)");
         roundtrip("#if x [y] else [z]");
         roundtrip("#if x {} else if y {} else {}");
         roundtrip("#while x {y}");