Rework strong and emph

- Star and underscore not parsed as strong/emph inside of words
- Stars/underscores must be balanced and they cannot go over paragraph break
- New `strong` and `emph` classes

27 files changed, 268 insertions, 148 deletions

diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index 2fa07d49..a453a357 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -213,15 +213,9 @@ impl Eval for MarkupNode {
             Self::Space => Node::Space,
             Self::Linebreak => Node::Linebreak,
             Self::Parbreak => Node::Parbreak,
-            Self::Strong => {
-                ctx.styles.toggle(TextNode::STRONG);
-                Node::new()
-            }
-            Self::Emph => {
-                ctx.styles.toggle(TextNode::EMPH);
-                Node::new()
-            }
             Self::Text(text) => Node::Text(text.clone()),
+            Self::Strong(strong) => strong.eval(ctx)?,
+            Self::Emph(emph) => emph.eval(ctx)?,
             Self::Raw(raw) => raw.eval(ctx)?,
             Self::Math(math) => math.eval(ctx)?,
             Self::Heading(heading) => heading.eval(ctx)?,
@@ -232,6 +226,22 @@ impl Eval for MarkupNode {
     }
 }
 
+impl Eval for StrongNode {
+    type Output = Node;
+
+    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+        Ok(self.body().eval(ctx)?.styled(TextNode::STRONG, true))
+    }
+}
+
+impl Eval for EmphNode {
+    type Output = Node;
+
+    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+        Ok(self.body().eval(ctx)?.styled(TextNode::EMPH, true))
+    }
+}
+
 impl Eval for RawNode {
     type Output = Node;
 
diff --git a/src/eval/styles.rs b/src/eval/styles.rs
index bdc01f1f..508996a1 100644
--- a/src/eval/styles.rs
+++ b/src/eval/styles.rs
@@ -87,19 +87,6 @@ impl StyleMap {
         }
     }
 
-    /// Toggle a boolean style property, removing it if it exists and inserting
-    /// it with `true` if it doesn't.
-    pub fn toggle<P: Property<Value = bool>>(&mut self, key: P) {
-        for (i, entry) in self.0.iter_mut().enumerate() {
-            if entry.is::<P>() {
-                self.0.swap_remove(i);
-                return;
-            }
-        }
-
-        self.0.push(Entry::new(key, true));
-    }
-
     /// Mark all contained properties as _scoped_. This means that they only
     /// apply to the first descendant node (of their type) in the hierarchy and
     /// not its children, too. This is used by class constructors.
diff --git a/src/library/mod.rs b/src/library/mod.rs
index 44f8f947..3115cc7a 100644
--- a/src/library/mod.rs
+++ b/src/library/mod.rs
@@ -93,6 +93,8 @@ pub fn new() -> Scope {
     std.def_class::<ParbreakNode>("parbreak");
     std.def_class::<LinebreakNode>("linebreak");
     std.def_class::<TextNode>("text");
+    std.def_class::<StrongNode>("strong");
+    std.def_class::<EmphNode>("emph");
     std.def_class::<DecoNode<Underline>>("underline");
     std.def_class::<DecoNode<Strikethrough>>("strike");
     std.def_class::<DecoNode<Overline>>("overline");
diff --git a/src/library/text.rs b/src/library/text.rs
index b8810ac6..6d7be323 100644
--- a/src/library/text.rs
+++ b/src/library/text.rs
@@ -150,6 +150,26 @@ impl Debug for TextNode {
     }
 }
 
+/// Strong text, rendered in boldface.
+pub struct StrongNode;
+
+#[class]
+impl StrongNode {
+    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Node> {
+        Ok(args.expect::<Node>("body")?.styled(TextNode::STRONG, true))
+    }
+}
+
+/// Emphasized text, rendered with an italic face.
+pub struct EmphNode;
+
+#[class]
+impl EmphNode {
+    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Node> {
+        Ok(args.expect::<Node>("body")?.styled(TextNode::EMPH, true))
+    }
+}
+
 /// A generic or named font family.
 #[derive(Clone, Eq, PartialEq, Hash)]
 pub enum FontFamily {
diff --git a/src/parse/incremental.rs b/src/parse/incremental.rs
index 9dd5bec1..fb927c24 100644
--- a/src/parse/incremental.rs
+++ b/src/parse/incremental.rs
@@ -435,10 +435,12 @@ impl NodeKind {
             | Self::LeftParen
             | Self::RightParen => SuccessionRule::Unsafe,
 
+            // These work similar to parentheses.
+            Self::Star | Self::Underscore => SuccessionRule::Unsafe,
+
             // Replacing an operator can change whether the parent is an
-            // operation which makes it unsafe. The star can appear in markup.
-            Self::Star
-            | Self::Comma
+            // operation which makes it unsafe.
+            Self::Comma
             | Self::Semicolon
             | Self::Colon
             | Self::Plus
diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index a9839ed6..b8ef3066 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -21,7 +21,7 @@ use crate::util::EcoString;
 /// Parse a source file.
 pub fn parse(src: &str) -> Rc<GreenNode> {
     let mut p = Parser::new(src, TokenMode::Markup);
-    markup(&mut p);
+    markup(&mut p, true);
     match p.finish().into_iter().next() {
         Some(Green::Node(node)) => node,
         _ => unreachable!(),
@@ -61,7 +61,7 @@ pub fn parse_markup(
 ) -> Option<(Vec<Green>, bool)> {
     let mut p = Parser::with_prefix(prefix, src, TokenMode::Markup);
     if min_column == 0 {
-        markup(&mut p);
+        markup(&mut p, true);
     } else {
         markup_indented(&mut p, min_column);
     }
@@ -128,8 +128,8 @@ pub fn parse_comment(
 }
 
 /// Parse markup.
-fn markup(p: &mut Parser) {
-    markup_while(p, true, 0, &mut |_| true)
+fn markup(p: &mut Parser, at_start: bool) {
+    markup_while(p, at_start, 0, &mut |_| true)
 }
 
 /// Parse markup that stays right of the given column.
@@ -191,8 +191,6 @@ fn markup_node(p: &mut Parser, at_start: &mut bool) {
         | NodeKind::EnDash
         | NodeKind::EmDash
         | NodeKind::NonBreakingSpace
-        | NodeKind::Emph
-        | NodeKind::Strong
         | NodeKind::Linebreak
         | NodeKind::Raw(_)
         | NodeKind::Math(_)
@@ -200,6 +198,9 @@ fn markup_node(p: &mut Parser, at_start: &mut bool) {
             p.eat();
         }
 
+        // Grouping markup.
+        NodeKind::Star => strong(p),
+        NodeKind::Underscore => emph(p),
         NodeKind::Eq => heading(p, *at_start),
         NodeKind::Minus => list_node(p, *at_start),
         NodeKind::EnumNumbering(_) => enum_node(p, *at_start),
@@ -227,6 +228,24 @@ fn markup_node(p: &mut Parser, at_start: &mut bool) {
     *at_start = false;
 }
 
+/// Parse strong content.
+fn strong(p: &mut Parser) {
+    p.perform(NodeKind::Strong, |p| {
+        p.start_group(Group::Strong);
+        markup(p, false);
+        p.end_group();
+    })
+}
+
+/// Parse emphasized content.
+fn emph(p: &mut Parser) {
+    p.perform(NodeKind::Emph, |p| {
+        p.start_group(Group::Emph);
+        markup(p, false);
+        p.end_group();
+    })
+}
+
 /// Parse a heading.
 fn heading(p: &mut Parser, at_start: bool) {
     let marker = p.marker();
@@ -234,7 +253,7 @@ fn heading(p: &mut Parser, at_start: bool) {
     p.eat_assert(&NodeKind::Eq);
     while p.eat_if(&NodeKind::Eq) {}
 
-    if at_start && p.peek().map_or(true, |kind| kind.is_whitespace()) {
+    if at_start && p.peek().map_or(true, |kind| kind.is_space()) {
         let column = p.column(p.prev_end());
         markup_indented(p, column);
         marker.end(p, NodeKind::Heading);
@@ -250,7 +269,7 @@ fn list_node(p: &mut Parser, at_start: bool) {
     let text: EcoString = p.peek_src().into();
     p.eat_assert(&NodeKind::Minus);
 
-    if at_start && p.peek().map_or(true, |kind| kind.is_whitespace()) {
+    if at_start && p.peek().map_or(true, |kind| kind.is_space()) {
         let column = p.column(p.prev_end());
         markup_indented(p, column);
         marker.end(p, NodeKind::List);
@@ -265,7 +284,7 @@ fn enum_node(p: &mut Parser, at_start: bool) {
     let text: EcoString = p.peek_src().into();
     p.eat();
 
-    if at_start && p.peek().map_or(true, |kind| kind.is_whitespace()) {
+    if at_start && p.peek().map_or(true, |kind| kind.is_space()) {
         let column = p.column(p.prev_end());
         markup_indented(p, column);
         marker.end(p, NodeKind::Enum);
@@ -620,7 +639,7 @@ fn params(p: &mut Parser, marker: Marker) {
 fn template(p: &mut Parser) {
     p.perform(NodeKind::Template, |p| {
         p.start_group(Group::Bracket);
-        markup(p);
+        markup(p, true);
         p.end_group();
     });
 }
diff --git a/src/parse/parser.rs b/src/parse/parser.rs
index 0184c198..db003e72 100644
--- a/src/parse/parser.rs
+++ b/src/parse/parser.rs
@@ -239,17 +239,18 @@ impl<'s> Parser<'s> {
     pub fn start_group(&mut self, kind: Group) {
         self.groups.push(GroupEntry { kind, prev_mode: self.tokens.mode() });
         self.tokens.set_mode(match kind {
-            Group::Bracket => TokenMode::Markup,
-            _ => TokenMode::Code,
+            Group::Bracket | Group::Strong | Group::Emph => TokenMode::Markup,
+            Group::Paren | Group::Brace | Group::Expr | Group::Imports => TokenMode::Code,
         });
 
-        self.repeek();
         match kind {
             Group::Paren => self.eat_assert(&NodeKind::LeftParen),
             Group::Bracket => self.eat_assert(&NodeKind::LeftBracket),
             Group::Brace => self.eat_assert(&NodeKind::LeftBrace),
-            Group::Expr => {}
-            Group::Imports => {}
+            Group::Strong => self.eat_assert(&NodeKind::Star),
+            Group::Emph => self.eat_assert(&NodeKind::Underscore),
+            Group::Expr => self.repeek(),
+            Group::Imports => self.repeek(),
         }
     }
 
@@ -273,6 +274,8 @@ impl<'s> Parser<'s> {
             Group::Paren => Some((NodeKind::RightParen, true)),
             Group::Bracket => Some((NodeKind::RightBracket, true)),
             Group::Brace => Some((NodeKind::RightBrace, true)),
+            Group::Strong => Some((NodeKind::Star, true)),
+            Group::Emph => Some((NodeKind::Underscore, true)),
             Group::Expr => Some((NodeKind::Semicolon, false)),
             Group::Imports => None,
         } {
@@ -322,9 +325,11 @@ impl<'s> Parser<'s> {
             Some(NodeKind::RightParen) => self.inside(Group::Paren),
             Some(NodeKind::RightBracket) => self.inside(Group::Bracket),
             Some(NodeKind::RightBrace) => self.inside(Group::Brace),
+            Some(NodeKind::Star) => self.inside(Group::Strong),
+            Some(NodeKind::Underscore) => self.inside(Group::Emph),
             Some(NodeKind::Semicolon) => self.inside(Group::Expr),
             Some(NodeKind::From) => self.inside(Group::Imports),
-            Some(NodeKind::Space(n)) => *n >= 1 && self.stop_at_newline(),
+            Some(NodeKind::Space(n)) => self.space_ends_group(*n),
             Some(_) => false,
             None => true,
         };
@@ -332,31 +337,34 @@ impl<'s> Parser<'s> {
 
     /// Returns whether the given type can be skipped over.
     fn is_trivia(&self, token: &NodeKind) -> bool {
-        Self::is_trivia_ext(token, self.stop_at_newline())
-    }
-
-    /// Returns whether the given type can be skipped over given the current
-    /// newline mode.
-    fn is_trivia_ext(token: &NodeKind, stop_at_newline: bool) -> bool {
         match token {
-            NodeKind::Space(n) => *n == 0 || !stop_at_newline,
+            NodeKind::Space(n) => !self.space_ends_group(*n),
             NodeKind::LineComment => true,
             NodeKind::BlockComment => true,
             _ => false,
         }
     }
 
-    /// Whether the active group must end at a newline.
-    fn stop_at_newline(&self) -> bool {
-        matches!(
-            self.groups.last().map(|group| group.kind),
-            Some(Group::Expr | Group::Imports)
-        )
+    /// Whether a space with the given number of newlines ends the current group.
+    fn space_ends_group(&self, n: usize) -> bool {
+        if n == 0 {
+            return false;
+        }
+
+        match self.groups.last().map(|group| group.kind) {
+            Some(Group::Strong | Group::Emph) => n >= 2,
+            Some(Group::Expr | Group::Imports) => n >= 1,
+            _ => false,
+        }
     }
 
-    /// Whether we are inside the given group.
+    /// Whether we are inside the given group (can be nested).
     fn inside(&self, kind: Group) -> bool {
-        self.groups.iter().any(|g| g.kind == kind)
+        self.groups
+            .iter()
+            .rev()
+            .take_while(|g| !kind.is_weak() || g.kind.is_weak())
+            .any(|g| g.kind == kind)
     }
 }
 
@@ -431,15 +439,20 @@ impl Marker {
         F: Fn(&Green) -> Result<(), &'static str>,
     {
         for child in &mut p.children[self.0 ..] {
-            if (p.tokens.mode() == TokenMode::Markup
-                || !Parser::is_trivia_ext(child.kind(), false))
-                && !child.kind().is_error()
-            {
-                if let Err(msg) = f(child) {
-                    let error = NodeKind::Error(ErrorPos::Full, msg.into());
-                    let inner = mem::take(child);
-                    *child = GreenNode::with_child(error, inner).into();
-                }
+            // Don't expose errors.
+            if child.kind().is_error() {
+                continue;
+            }
+
+            // Don't expose trivia in code.
+            if p.tokens.mode() == TokenMode::Code && child.kind().is_trivia() {
+                continue;
+            }
+
+            if let Err(msg) = f(child) {
+                let error = NodeKind::Error(ErrorPos::Full, msg.into());
+                let inner = mem::take(child);
+                *child = GreenNode::with_child(error, inner).into();
             }
         }
     }
@@ -485,12 +498,23 @@ pub enum Group {
     Brace,
     /// A parenthesized group: `(...)`.
     Paren,
+    /// A group surrounded with stars: `*...*`.
+    Strong,
+    /// A group surrounded with underscore: `_..._`.
+    Emph,
     /// A group ended by a semicolon or a line break: `;`, `\n`.
     Expr,
     /// A group for import items, ended by a semicolon, line break or `from`.
     Imports,
 }
 
+impl Group {
+    /// Whether the group can only force other weak groups to end.
+    fn is_weak(self) -> bool {
+        matches!(self, Group::Strong | Group::Emph)
+    }
+}
+
 /// Allows parser methods to use the try operator. Never returned top-level
 /// because the parser recovers from all errors.
 pub type ParseResult<T = ()> = Result<T, ParseError>;
diff --git a/src/parse/tokens.rs b/src/parse/tokens.rs
index eef7a72d..d741dea1 100644
--- a/src/parse/tokens.rs
+++ b/src/parse/tokens.rs
@@ -123,8 +123,8 @@ impl<'s> Tokens<'s> {
 
             // Markup.
             '~' => NodeKind::NonBreakingSpace,
-            '*' => NodeKind::Strong,
-            '_' => NodeKind::Emph,
+            '*' if !self.in_word() => NodeKind::Star,
+            '_' if !self.in_word() => NodeKind::Underscore,
             '`' => self.raw(),
             '$' => self.math(),
             '-' => self.hyph(),
@@ -527,6 +527,13 @@ impl<'s> Tokens<'s> {
         NodeKind::BlockComment
     }
 
+    fn in_word(&self) -> bool {
+        let alphanumeric = |c: Option<char>| c.map_or(false, |c| c.is_alphanumeric());
+        let prev = self.s.get(.. self.s.last_index()).chars().next_back();
+        let next = self.s.peek();
+        alphanumeric(prev) && alphanumeric(next)
+    }
+
     fn maybe_in_url(&self) -> bool {
         self.mode == TokenMode::Markup && self.s.eaten().ends_with(":/")
     }
@@ -651,7 +658,7 @@ mod tests {
                 ('/', None, "[", LeftBracket),
                 ('/', None, "//", LineComment),
                 ('/', None, "/**/", BlockComment),
-                ('/', Some(Markup), "*", Strong),
+                ('/', Some(Markup), "*", Star),
                 ('/', Some(Markup), "$ $", Math(" ", false)),
                 ('/', Some(Markup), r"\\", Escape('\\')),
                 ('/', Some(Markup), "#let", Let),
@@ -790,8 +797,8 @@ mod tests {
     #[test]
     fn test_tokenize_markup_symbols() {
         // Test markup tokens.
-        t!(Markup[" a1"]: "*"   => Strong);
-        t!(Markup: "_"          => Emph);
+        t!(Markup[" a1"]: "*"   => Star);
+        t!(Markup: "_"          => Underscore);
         t!(Markup[""]: "==="    => Eq, Eq, Eq);
         t!(Markup["a1/"]: "= "  => Eq, Space(0));
         t!(Markup: "~"          => NonBreakingSpace);
diff --git a/src/syntax/ast.rs b/src/syntax/ast.rs
index 13c639f9..560d7c30 100644
--- a/src/syntax/ast.rs
+++ b/src/syntax/ast.rs
@@ -63,8 +63,6 @@ impl Markup {
             NodeKind::Space(_) => Some(MarkupNode::Space),
             NodeKind::Linebreak => Some(MarkupNode::Linebreak),
             NodeKind::Parbreak => Some(MarkupNode::Parbreak),
-            NodeKind::Strong => Some(MarkupNode::Strong),
-            NodeKind::Emph => Some(MarkupNode::Emph),
             NodeKind::Text(s) | NodeKind::TextInLine(s) => {
                 Some(MarkupNode::Text(s.clone()))
             }
@@ -72,8 +70,10 @@ impl Markup {
             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::Strong => node.cast().map(MarkupNode::Strong),
+            NodeKind::Emph => node.cast().map(MarkupNode::Emph),
             NodeKind::Raw(raw) => Some(MarkupNode::Raw(raw.as_ref().clone())),
+            NodeKind::Math(math) => Some(MarkupNode::Math(math.as_ref().clone())),
             NodeKind::Heading => node.cast().map(MarkupNode::Heading),
             NodeKind::List => node.cast().map(MarkupNode::List),
             NodeKind::Enum => node.cast().map(MarkupNode::Enum),
@@ -91,12 +91,12 @@ pub enum MarkupNode {
     Linebreak,
     /// A paragraph break: Two or more newlines.
     Parbreak,
-    /// Strong text was enabled / disabled: `*`.
-    Strong,
-    /// Emphasized text was enabled / disabled: `_`.
-    Emph,
     /// Plain text.
     Text(EcoString),
+    /// Strong content: `*Strong*`.
+    Strong(StrongNode),
+    /// Emphasized content: `_Emphasized_`.
+    Emph(EmphNode),
     /// A raw block with optional syntax highlighting: `` `...` ``.
     Raw(RawNode),
     /// A math formula: `$a^2 = b^2 + c^2$`.
@@ -111,6 +111,32 @@ pub enum MarkupNode {
     Expr(Expr),
 }
 
+node! {
+    /// Strong content: `*Strong*`.
+    StrongNode: Strong
+}
+
+impl StrongNode {
+    /// The contents of the strong node.
+    pub fn body(&self) -> Markup {
+        self.0.cast_first_child().expect("strong node is missing markup body")
+    }
+}
+
+node! {
+    /// Emphasized content: `_Emphasized_`.
+    EmphNode: Emph
+}
+
+impl EmphNode {
+    /// The contents of the emphasis node.
+    pub fn body(&self) -> Markup {
+        self.0
+            .cast_first_child()
+            .expect("emphasis node is missing markup body")
+    }
+}
+
 /// A raw block with optional syntax highlighting: `` `...` ``.
 #[derive(Debug, Clone, PartialEq)]
 pub struct RawNode {
diff --git a/src/syntax/highlight.rs b/src/syntax/highlight.rs
index 315e8f17..b806b4e4 100644
--- a/src/syntax/highlight.rs
+++ b/src/syntax/highlight.rs
@@ -151,7 +151,10 @@ impl Category {
             NodeKind::From => Some(Category::Keyword),
             NodeKind::Include => Some(Category::Keyword),
             NodeKind::Plus => Some(Category::Operator),
-            NodeKind::Star => Some(Category::Operator),
+            NodeKind::Star => match parent.kind() {
+                NodeKind::Strong => None,
+                _ => Some(Category::Operator),
+            },
             NodeKind::Slash => Some(Category::Operator),
             NodeKind::PlusEq => Some(Category::Operator),
             NodeKind::HyphEq => Some(Category::Operator),
@@ -191,6 +194,7 @@ impl Category {
             NodeKind::Str(_) => Some(Category::String),
             NodeKind::Error(_, _) => Some(Category::Invalid),
             NodeKind::Unknown(_) => Some(Category::Invalid),
+            NodeKind::Underscore => None,
             NodeKind::Markup(_) => None,
             NodeKind::Space(_) => None,
             NodeKind::Parbreak => None,
@@ -276,11 +280,7 @@ mod tests {
             assert_eq!(vec, goal);
         }
 
-        test("= *AB*", &[
-            (0 .. 6, Heading),
-            (2 .. 3, Strong),
-            (5 .. 6, Strong),
-        ]);
+        test("= *AB*", &[(0 .. 6, Heading), (2 .. 6, Strong)]);
 
         test("#f(x + 1)", &[
             (0 .. 2, Function),
diff --git a/src/syntax/mod.rs b/src/syntax/mod.rs
index 9b606e0e..fdd50a7a 100644
--- a/src/syntax/mod.rs
+++ b/src/syntax/mod.rs
@@ -496,6 +496,8 @@ pub enum NodeKind {
     RightParen,
     /// An asterisk: `*`.
     Star,
+    /// An underscore: `_`.
+    Underscore,
     /// A comma: `,`.
     Comma,
     /// A semicolon: `;`.
@@ -599,25 +601,25 @@ pub enum NodeKind {
     /// A slash and the letter "u" followed by a hexadecimal unicode entity
     /// enclosed in curly braces: `\u{1F5FA}`.
     Escape(char),
-    /// Strong text was enabled / disabled: `*`.
+    /// Strong content: `*Strong*`.
     Strong,
-    /// Emphasized text was enabled / disabled: `_`.
+    /// Emphasized content: `_Emphasized_`.
     Emph,
+    /// An arbitrary number of backticks followed by inner contents, terminated
+    /// with the same number of backticks: `` `...` ``.
+    Raw(Rc<RawNode>),
+    /// Dollar signs surrounding inner contents.
+    Math(Rc<MathNode>),
     /// A section heading: `= Introduction`.
     Heading,
+    /// An item in an unordered list: `- ...`.
+    List,
     /// An item in an enumeration (ordered list): `1. ...`.
     Enum,
     /// A numbering: `23.`.
     ///
     /// Can also exist without the number: `.`.
     EnumNumbering(Option<usize>),
-    /// An item in an unordered list: `- ...`.
-    List,
-    /// An arbitrary number of backticks followed by inner contents, terminated
-    /// with the same number of backticks: `` `...` ``.
-    Raw(Rc<RawNode>),
-    /// Dollar signs surrounding inner contents.
-    Math(Rc<MathNode>),
     /// An identifier: `center`.
     Ident(EcoString),
     /// A boolean: `true`, `false`.
@@ -736,14 +738,14 @@ impl NodeKind {
         matches!(self, Self::LeftParen | Self::RightParen)
     }
 
-    /// Whether this is whitespace.
-    pub fn is_whitespace(&self) -> bool {
-        matches!(self, Self::Space(_) | Self::Parbreak)
+    /// Whether this is a space.
+    pub fn is_space(&self) -> bool {
+        matches!(self, Self::Space(_))
     }
 
     /// Whether this is trivia.
     pub fn is_trivia(&self) -> bool {
-        self.is_whitespace() || matches!(self, Self::LineComment | Self::BlockComment)
+        self.is_space() || matches!(self, Self::LineComment | Self::BlockComment)
     }
 
     /// Whether this is some kind of error.
@@ -761,7 +763,7 @@ impl NodeKind {
         }
     }
 
-    /// Which mode this token can appear in, in both if `None`.
+    /// Which mode this node can appear in, in both if `None`.
     pub fn mode(&self) -> Option<TokenMode> {
         match self {
             Self::Markup(_)
@@ -814,6 +816,7 @@ impl NodeKind {
             Self::LeftParen => "opening paren",
             Self::RightParen => "closing paren",
             Self::Star => "star",
+            Self::Underscore => "underscore",
             Self::Comma => "comma",
             Self::Semicolon => "semicolon",
             Self::Colon => "colon",
@@ -864,14 +867,14 @@ impl NodeKind {
             Self::EnDash => "en dash",
             Self::EmDash => "em dash",
             Self::Escape(_) => "escape sequence",
-            Self::Strong => "strong",
-            Self::Emph => "emphasis",
+            Self::Strong => "strong content",
+            Self::Emph => "emphasized content",
+            Self::Raw(_) => "raw block",
+            Self::Math(_) => "math formula",
+            Self::List => "list item",
             Self::Heading => "heading",
             Self::Enum => "enumeration item",
             Self::EnumNumbering(_) => "enumeration item numbering",
-            Self::List => "list item",
-            Self::Raw(_) => "raw block",
-            Self::Math(_) => "math formula",
             Self::Ident(_) => "identifier",
             Self::Bool(_) => "boolean",
             Self::Int(_) => "integer",
diff --git a/src/syntax/pretty.rs b/src/syntax/pretty.rs
index e8110262..07ab979b 100644
--- a/src/syntax/pretty.rs
+++ b/src/syntax/pretty.rs
@@ -95,8 +95,8 @@ impl Pretty for MarkupNode {
             Self::Space => p.push(' '),
             Self::Linebreak => p.push_str(r"\"),
             Self::Parbreak => p.push_str("\n\n"),
-            Self::Strong => p.push('*'),
-            Self::Emph => p.push('_'),
+            Self::Strong(strong) => strong.pretty(p),
+            Self::Emph(emph) => emph.pretty(p),
             Self::Text(text) => p.push_str(text),
             Self::Raw(raw) => raw.pretty(p),
             Self::Math(math) => math.pretty(p),
@@ -113,6 +113,22 @@ impl Pretty for MarkupNode {
     }
 }
 
+impl Pretty for StrongNode {
+    fn pretty(&self, p: &mut Printer) {
+        p.push('*');
+        self.body().pretty(p);
+        p.push('*');
+    }
+}
+
+impl Pretty for EmphNode {
+    fn pretty(&self, p: &mut Printer) {
+        p.push('_');
+        self.body().pretty(p);
+        p.push('_');
+    }
+}
+
 impl Pretty for RawNode {
     fn pretty(&self, p: &mut Printer) {
         // Find out how many backticks we need.
@@ -604,12 +620,12 @@ mod tests {
     #[test]
     fn test_pretty_print_markup() {
         // Basic stuff.
-        roundtrip("*");
-        roundtrip("_");
         roundtrip(" ");
+        roundtrip("*ab*");
         roundtrip("\\ ");
         roundtrip("\n\n");
         roundtrip("hi");
+        roundtrip("_ab_");
         roundtrip("= *Ok*");
         roundtrip("- Ok");
 
diff --git a/tests/ref/markup/emph-strong.png b/tests/ref/markup/emph-strong.png
new file mode 100644
index 00000000..cce98812
--- /dev/null
+++ b/tests/ref/markup/emph-strong.png
diff --git a/tests/ref/markup/emph.png b/tests/ref/markup/emph.png
deleted file mode 100644
index 6b3bfb2d..00000000
--- a/tests/ref/markup/emph.png
+++ /dev/null
diff --git a/tests/ref/markup/strong.png b/tests/ref/markup/strong.png
deleted file mode 100644
index 53062e9a..00000000
--- a/tests/ref/markup/strong.png
+++ /dev/null
diff --git a/tests/ref/style/set-toggle.png b/tests/ref/style/set-toggle.png
deleted file mode 100644
index daaa3d6c..00000000
--- a/tests/ref/style/set-toggle.png
+++ /dev/null
diff --git a/tests/typ/code/ops.typ b/tests/typ/code/ops.typ
index be2cdb48..e3e2e855 100644
--- a/tests/typ/code/ops.typ
+++ b/tests/typ/code/ops.typ
@@ -4,7 +4,7 @@
 ---
 // Test template addition.
 // Ref: true
-{[*Hello ] + [world!]}
+{[*Hello* ] + [world!]}
 
 ---
 // Test math operators.
diff --git a/tests/typ/markup/emph-strong.typ b/tests/typ/markup/emph-strong.typ
new file mode 100644
index 00000000..9bdb5059
--- /dev/null
+++ b/tests/typ/markup/emph-strong.typ
@@ -0,0 +1,33 @@
+// Test emph and strong.
+
+---
+// Basic.
+_Emphasized and *strong* words!_
+
+// Inside of a word it's a normal underscore or star.
+hello_world Nutzer*innen
+
+// Can contain paragraph in child template.
+_Still [
+
+] emphasized._
+
+---
+// Inside of words can still use the functions.
+P#strong[art]ly em#emph[phas]ized.
+
+---
+// Error: 13 expected underscore
+#box[_Scoped] to body.
+
+---
+// Ends at paragraph break.
+// Error: 7 expected underscore
+_Hello
+
+World
+
+---
+// Error: 1:12 expected star
+// Error: 2:1 expected star
+_Cannot *be_ interleaved*
diff --git a/tests/typ/markup/emph.typ b/tests/typ/markup/emph.typ
deleted file mode 100644
index 77ac2c72..00000000
--- a/tests/typ/markup/emph.typ
+++ /dev/null
@@ -1,11 +0,0 @@
-// Test emphasis toggle.
-
----
-// Basic.
-_Emphasized!_
-
-// Inside of words.
-Partly em_phas_ized.
-
-// Scoped to body.
-#box[_Scoped] to body.
diff --git a/tests/typ/markup/escape.typ b/tests/typ/markup/escape.typ
index c039e0b7..87d2b83a 100644
--- a/tests/typ/markup/escape.typ
+++ b/tests/typ/markup/escape.typ
@@ -32,4 +32,4 @@ let f() , ; : | + - /= == 12 "string"
 ---
 // Unterminated.
 // Error: 6 expected closing brace
-\u{41*Bold*
+\u{41[*Bold*]
diff --git a/tests/typ/markup/strong.typ b/tests/typ/markup/strong.typ
deleted file mode 100644
index d396cc2d..00000000
--- a/tests/typ/markup/strong.typ
+++ /dev/null
@@ -1,11 +0,0 @@
-// Test strong toggle.
-
----
-// Basic.
-*Strong!*
-
-// Inside of words.
-Partly str*ength*ened.
-
-// Scoped to body.
-#box[*Scoped] to body.
diff --git a/tests/typ/style/set-toggle.typ b/tests/typ/style/set-toggle.typ
deleted file mode 100644
index 9f26bdf7..00000000
--- a/tests/typ/style/set-toggle.typ
+++ /dev/null
@@ -1,10 +0,0 @@
-// Test set rules for toggleable booleans.
-
----
-// Test toggling and untoggling.
-*AB_C*DE
-*_*
-
----
-// Test toggling and nested templates.
-*A[B*[_C]]D*E
diff --git a/tests/typ/style/wrap.typ b/tests/typ/style/wrap.typ
index 1ff3cc95..2fa7716e 100644
--- a/tests/typ/style/wrap.typ
+++ b/tests/typ/style/wrap.typ
@@ -16,7 +16,7 @@ in booklovers and the great fulfiller of human need.
 
 ---
 // Test wrap in template.
-A [_B #wrap c in [*#c*]; C] D
+A [_B #wrap c in [*#c*]; C_] D
 
 ---
 // Test wrap style precedence.
diff --git a/tests/typ/text/bidi.typ b/tests/typ/text/bidi.typ
index 658c7fa6..09e23558 100644
--- a/tests/typ/text/bidi.typ
+++ b/tests/typ/text/bidi.typ
@@ -10,7 +10,7 @@
 ---
 // Test that consecutive, embedded  LTR runs stay LTR.
 // Here, we have two runs: "A" and italic "B".
-#let content = [أنت A_B_مطرC]
+#let content = [أنت A#emph[B]مطرC]
 #set text(serif, "Noto Sans Arabic")
 #par(lang: "ar", content)
 #par(lang: "de", content)
@@ -18,7 +18,7 @@
 ---
 // Test that consecutive, embedded RTL runs stay RTL.
 // Here, we have three runs: "גֶ", bold "שֶׁ", and "ם".
-#let content = [Aגֶ*שֶׁ*םB]
+#let content = [Aגֶ#strong[שֶׁ]םB]
 #set text(serif, "Noto Serif Hebrew")
 #par(lang: "he", content)
 #par(lang: "de", content)
diff --git a/tests/typ/text/linebreaks.typ b/tests/typ/text/linebreaks.typ
index 5f886381..de99f5ed 100644
--- a/tests/typ/text/linebreaks.typ
+++ b/tests/typ/text/linebreaks.typ
@@ -10,7 +10,7 @@ Supercalifragilisticexpialidocious Expialigoricmetrioxidation.
 
 ---
 // Test that there are no unwanted line break opportunities on run change.
-This is partly emp_has_ized.
+This is partly emp#emph[has]ized.
 
 ---
 Hard \ break.
diff --git a/tests/typeset.rs b/tests/typeset.rs
index 5437860b..64749975 100644
--- a/tests/typeset.rs
+++ b/tests/typeset.rs
@@ -259,6 +259,8 @@ fn test_part(
     debug: bool,
     rng: &mut LinearShift,
 ) -> (bool, bool, Vec<Rc<Frame>>) {
+    let mut ok = true;
+
     let id = ctx.sources.provide(src_path, src);
     let source = ctx.sources.get(id);
     if debug {
@@ -267,7 +269,8 @@ fn test_part(
 
     let (local_compare_ref, mut ref_errors) = parse_metadata(&source);
     let compare_ref = local_compare_ref.unwrap_or(compare_ref);
-    let mut ok = test_reparse(ctx.sources.get(id).src(), i, rng);
+
+    ok &= test_reparse(ctx.sources.get(id).src(), i, rng);
 
     let (frames, mut errors) = match ctx.evaluate(id) {
         Ok(module) => {
diff --git a/tools/support/typst.tmLanguage.json b/tools/support/typst.tmLanguage.json
index 78809b4e..577804fc 100644
--- a/tools/support/typst.tmLanguage.json
+++ b/tools/support/typst.tmLanguage.json
@@ -44,15 +44,15 @@
         },
         {
           "name": "markup.bold.typst",
-          "begin": "\\*",
-          "end": "\\*|(?=\\])",
+          "begin": "(^\\*|\\*$|((?<=\\W|_)\\*)|(\\*(?=\\W|_)))",
+          "end": "(^\\*|\\*$|((?<=\\W|_)\\*)|(\\*(?=\\W|_)))|\n|(?=\\])",
           "captures": { "0": { "name": "punctuation.definition.bold.typst" } },
           "patterns": [{ "include": "#markup" }]
         },
         {
           "name": "markup.italic.typst",
-          "begin": "_",
-          "end": "_|(?=\\])",
+          "begin": "(^_|_$|((?<=\\W|_)_)|(_(?=\\W|_)))",
+          "end": "(^_|_$|((?<=\\W|_)_)|(_(?=\\W|_)))|\n|(?=\\])",
           "captures": { "0": { "name": "punctuation.definition.italic.typst" } },
           "patterns": [{ "include": "#markup" }]
         },