Better parser testing ✅

8 files changed, 616 insertions, 632 deletions

diff --git a/src/color.rs b/src/color.rs
index da26d2e2..9dc31c30 100644
--- a/src/color.rs
+++ b/src/color.rs
@@ -122,4 +122,16 @@ mod tests {
         test("233", 0x22, 0x33, 0x33, 0xff);
         test("111b", 0x11, 0x11, 0x11, 0xbb);
     }
+
+    #[test]
+    fn parse_invalid_colors() {
+        fn test(hex: &str) {
+            assert_eq!(RgbaColor::from_str(hex), Err(ParseRgbaError));
+        }
+
+        test("12345");
+        test("a5");
+        test("14B2AH");
+        test("f075ff011");
+    }
 }
diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index ed73b07c..c4da1fe0 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -18,9 +18,9 @@ use std::rc::Rc;
 
 use fontdock::FontStyle;
 
+use crate::color::Color;
 use crate::diag::Diag;
 use crate::diag::{Deco, Feedback, Pass};
-use crate::color::Color;
 use crate::env::SharedEnv;
 use crate::geom::{BoxAlign, Dir, Flow, Gen, Length, Linear, Relative, Sides, Size};
 use crate::layout::{
@@ -328,6 +328,11 @@ impl Eval for SynNode {
 
     fn eval(&self, ctx: &mut EvalContext) -> Self::Output {
         match self {
+            SynNode::Text(text) => {
+                let node = ctx.make_text_node(text.clone());
+                ctx.push(node);
+            }
+
             SynNode::Space => {
                 let em = ctx.state.font.font_size();
                 ctx.push(Spacing {
@@ -336,11 +341,6 @@ impl Eval for SynNode {
                 });
             }
 
-            SynNode::Text(text) => {
-                let node = ctx.make_text_node(text.clone());
-                ctx.push(node);
-            }
-
             SynNode::Linebreak => {
                 ctx.end_par_group();
                 ctx.start_par_group();
@@ -356,10 +356,12 @@ impl Eval for SynNode {
                 ctx.start_par_group();
             }
 
-            SynNode::Emph => ctx.state.font.emph ^= true,
             SynNode::Strong => ctx.state.font.strong ^= true,
+            SynNode::Emph => ctx.state.font.emph ^= true,
+
             SynNode::Heading(heading) => heading.eval(ctx),
             SynNode::Raw(raw) => raw.eval(ctx),
+
             SynNode::Expr(expr) => expr.eval(ctx).eval(ctx),
         }
     }
diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index bf522fc8..99cc9d10 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -33,10 +33,10 @@ fn tree(p: &mut Parser) -> SynTree {
     let mut tree = vec![];
     while !p.eof() {
         if let Some(node) = p.span_if(|p| node(p, at_start)) {
-            if node.v == SynNode::Parbreak {
-                at_start = true;
-            } else if node.v != SynNode::Space {
-                at_start = false;
+            match node.v {
+                SynNode::Parbreak => at_start = true,
+                SynNode::Space => {}
+                _ => at_start = false,
             }
             tree.push(node);
         }
@@ -46,9 +46,7 @@ fn tree(p: &mut Parser) -> SynTree {
 
 /// Parse a syntax node.
 fn node(p: &mut Parser, at_start: bool) -> Option<SynNode> {
-    let start = p.next_start();
-    let node = match p.eat()? {
-        // Spaces.
+    let node = match p.peek()? {
         Token::Space(newlines) => {
             if newlines < 2 {
                 SynNode::Space
@@ -56,61 +54,59 @@ fn node(p: &mut Parser, at_start: bool) -> Option<SynNode> {
                 SynNode::Parbreak
             }
         }
-
-        // Text.
         Token::Text(text) => SynNode::Text(text.into()),
 
-        // Comments.
-        Token::LineComment(_) | Token::BlockComment(_) => return None,
+        Token::LineComment(_) | Token::BlockComment(_) => {
+            p.eat();
+            return None;
+        }
 
-        // Markup.
         Token::Star => SynNode::Strong,
         Token::Underscore => SynNode::Emph,
+        Token::Tilde => SynNode::Text("\u{00A0}".into()),
+        Token::Backslash => SynNode::Linebreak,
         Token::Hashtag => {
             if at_start {
-                SynNode::Heading(heading(p, start))
+                return Some(SynNode::Heading(heading(p)));
             } else {
-                SynNode::Text(p.eaten_from(start).into())
+                SynNode::Text(p.get(p.peek_span()).into())
             }
         }
-        Token::Tilde => SynNode::Text("\u{00A0}".into()),
-        Token::Backslash => SynNode::Linebreak,
-        Token::UnicodeEscape(token) => SynNode::Text(unicode_escape(p, token, start)),
-        Token::Raw(token) => SynNode::Raw(raw(p, token)),
+        Token::Raw(t) => SynNode::Raw(raw(p, t)),
+        Token::UnicodeEscape(t) => SynNode::Text(unicode_escape(p, t)),
 
-        // Functions.
         Token::LeftBracket => {
-            p.jump(start);
-            SynNode::Expr(Expr::Call(bracket_call(p)))
+            return Some(SynNode::Expr(Expr::Call(bracket_call(p))));
         }
 
-        // Blocks.
         Token::LeftBrace => {
-            p.jump(start);
-            SynNode::Expr(block_expr(p)?)
+            return Some(SynNode::Expr(block_expr(p)?));
         }
 
-        // Bad tokens.
         _ => {
-            p.jump(start);
             p.diag_unexpected();
             return None;
         }
     };
+    p.eat();
     Some(node)
 }
 
 /// Parse a heading.
-fn heading(p: &mut Parser, start: Pos) -> NodeHeading {
-    // Parse the section depth.
-    let mut level = 0u8;
-    while p.eat_if(Token::Hashtag) {
-        level = level.saturating_add(1);
-    }
+fn heading(p: &mut Parser) -> NodeHeading {
+    // Count hashtags.
+    let mut level = p.span(|p| {
+        p.eat_assert(Token::Hashtag);
+
+        let mut level = 0u8;
+        while p.eat_if(Token::Hashtag) {
+            level = level.saturating_add(1);
+        }
+        level
+    });
 
-    let mut level = level.span_with(start .. p.last_end());
     if level.v > 5 {
-        p.diag(warning!(level.span, "section depth should be at most 6"));
+        p.diag(warning!(level.span, "section depth should not exceed 6"));
         level.v = 5;
     }
 
@@ -125,25 +121,23 @@ fn heading(p: &mut Parser, start: Pos) -> NodeHeading {
     NodeHeading { level, contents }
 }
 
-/// Parse a raw block.
+/// Handle a raw block.
 fn raw(p: &mut Parser, token: TokenRaw) -> NodeRaw {
+    let span = p.peek_span();
     let raw = resolve::resolve_raw(token.text, token.backticks);
-
     if !token.terminated {
-        p.diag(error!(p.last_end(), "expected backtick(s)"));
+        p.diag(error!(span.end, "expected backtick(s)"));
     }
-
     raw
 }
 
-/// Parse a unicode escape sequence.
-fn unicode_escape(p: &mut Parser, token: TokenUnicodeEscape, start: Pos) -> String {
-    let span = Span::new(start, p.last_end());
+/// Handle a unicode escape sequence.
+fn unicode_escape(p: &mut Parser, token: TokenUnicodeEscape) -> String {
+    let span = p.peek_span();
     let text = if let Some(c) = resolve::resolve_hex(token.sequence) {
         c.to_string()
     } else {
-        // Print out the escape sequence verbatim if it is
-        // invalid.
+        // Print out the escape sequence verbatim if it is invalid.
         p.diag(error!(span, "invalid unicode escape sequence"));
         p.get(span).into()
     };
@@ -155,6 +149,24 @@ fn unicode_escape(p: &mut Parser, token: TokenUnicodeEscape, start: Pos) -> Stri
     text
 }
 
+/// Parse a block expression.
+fn block_expr(p: &mut Parser) -> Option<Expr> {
+    p.push_mode(TokenMode::Header);
+    p.start_group(Group::Brace);
+    let expr = expr(p);
+    p.pop_mode();
+    p.end_group();
+    expr
+}
+
+/// Parse a parenthesized function call.
+fn paren_call(p: &mut Parser, name: Spanned<Ident>) -> ExprCall {
+    p.start_group(Group::Paren);
+    let args = p.span(|p| dict_contents(p).0);
+    p.end_group();
+    ExprCall { name, args }
+}
+
 /// Parse a bracketed function call.
 fn bracket_call(p: &mut Parser) -> ExprCall {
     p.push_mode(TokenMode::Header);
@@ -180,7 +192,7 @@ fn bracket_call(p: &mut Parser) -> ExprCall {
 
     while let Some(mut top) = outer.pop() {
         let span = inner.span;
-        let node = inner.map(Expr::Call).map(SynNode::Expr);
+        let node = inner.map(|c| SynNode::Expr(Expr::Call(c)));
         let expr = Expr::Lit(Lit::Content(vec![node])).span_with(span);
         top.v.args.v.0.push(LitDictEntry { key: None, expr });
         inner = top;
@@ -220,64 +232,35 @@ fn bracket_body(p: &mut Parser) -> SynTree {
     tree
 }
 
-/// Parse a parenthesized function call.
-fn paren_call(p: &mut Parser, name: Spanned<Ident>) -> ExprCall {
-    p.start_group(Group::Paren);
-    let args = p.span(|p| dict_contents(p).0);
-    p.end_group();
-    ExprCall { name, args }
-}
-
-/// Parse a block expression.
-fn block_expr(p: &mut Parser) -> Option<Expr> {
-    p.push_mode(TokenMode::Header);
-    p.start_group(Group::Brace);
-    let expr = expr(p);
-    p.pop_mode();
-    p.end_group();
-    expr
-}
-
 /// Parse the contents of a dictionary.
 fn dict_contents(p: &mut Parser) -> (LitDict, bool) {
     let mut dict = LitDict::new();
+    let mut missing_coma = None;
     let mut comma_and_keyless = true;
-    let mut expected_comma = None;
-
-    loop {
-        if p.eof() {
-            break;
-        }
-
-        let entry = if let Some(entry) = dict_entry(p) {
-            entry
-        } else {
-            expected_comma = None;
-            p.diag_unexpected();
-            continue;
-        };
-
-        if let Some(pos) = expected_comma.take() {
-            p.diag_expected_at("comma", pos);
-        }
 
-        if let Some(key) = &entry.key {
-            comma_and_keyless = false;
-            p.deco(Deco::DictKey.span_with(key.span));
-        }
+    while !p.eof() {
+        if let Some(entry) = dict_entry(p) {
+            let behind = entry.expr.span.end;
+            if let Some(pos) = missing_coma.take() {
+                p.diag_expected_at("comma", pos);
+            }
 
-        let behind = entry.expr.span.end;
-        dict.0.push(entry);
+            if let Some(key) = &entry.key {
+                comma_and_keyless = false;
+                p.deco(Deco::DictKey.span_with(key.span));
+            }
 
-        if p.eof() {
-            break;
-        }
+            dict.0.push(entry);
+            if p.eof() {
+                break;
+            }
 
-        if !p.eat_if(Token::Comma) {
-            expected_comma = Some(behind);
+            if p.eat_if(Token::Comma) {
+                comma_and_keyless = false;
+            } else {
+                missing_coma = Some(behind);
+            }
         }
-
-        comma_and_keyless = false;
     }
 
     let coercible = comma_and_keyless && !dict.0.is_empty();
@@ -291,15 +274,10 @@ fn dict_entry(p: &mut Parser) -> Option<LitDictEntry> {
             // Key-value pair.
             Some(Token::Colon) => {
                 p.eat_assert(Token::Colon);
-                if let Some(expr) = p.span_if(expr) {
-                    Some(LitDictEntry {
-                        key: Some(ident.map(|id| DictKey::Str(id.0))),
-                        expr,
-                    })
-                } else {
-                    p.diag_expected("value");
-                    None
-                }
+                p.span_if(expr).map(|expr| LitDictEntry {
+                    key: Some(ident.map(|id| DictKey::Str(id.0))),
+                    expr,
+                })
             }
 
             // Function call.
@@ -318,16 +296,14 @@ fn dict_entry(p: &mut Parser) -> Option<LitDictEntry> {
                 expr: ident.map(|id| Expr::Lit(Lit::Ident(id))),
             }),
         }
-    } else if let Some(expr) = p.span_if(expr) {
-        Some(LitDictEntry { key: None, expr })
     } else {
-        None
+        p.span_if(expr).map(|expr| LitDictEntry { key: None, expr })
     }
 }
 
 /// Parse an expression: `term (+ term)*`.
 fn expr(p: &mut Parser) -> Option<Expr> {
-    binops(p, "summand", term, |token| match token {
+    binops(p, term, |token| match token {
         Token::Plus => Some(BinOp::Add),
         Token::Hyphen => Some(BinOp::Sub),
         _ => None,
@@ -336,7 +312,7 @@ fn expr(p: &mut Parser) -> Option<Expr> {
 
 /// Parse a term: `factor (* factor)*`.
 fn term(p: &mut Parser) -> Option<Expr> {
-    binops(p, "factor", factor, |token| match token {
+    binops(p, factor, |token| match token {
         Token::Star => Some(BinOp::Mul),
         Token::Slash => Some(BinOp::Div),
         _ => None,
@@ -346,27 +322,20 @@ fn term(p: &mut Parser) -> Option<Expr> {
 /// Parse binary operations of the from `a (<op> b)*`.
 fn binops(
     p: &mut Parser,
-    operand_name: &str,
     operand: fn(&mut Parser) -> Option<Expr>,
     op: fn(Token) -> Option<BinOp>,
 ) -> Option<Expr> {
     let mut lhs = p.span_if(operand)?;
 
-    loop {
-        if let Some(op) = p.span_if(|p| p.eat_map(op)) {
-            if let Some(rhs) = p.span_if(operand) {
-                let span = lhs.span.join(rhs.span);
-                let expr = Expr::Binary(ExprBinary {
-                    lhs: Box::new(lhs),
-                    op,
-                    rhs: Box::new(rhs),
-                });
-                lhs = expr.span_with(span);
-            } else {
-                let span = lhs.span.join(op.span);
-                p.diag(error!(span, "missing right {}", operand_name));
-                break;
-            }
+    while let Some(op) = p.span_if(|p| p.eat_map(op)) {
+        if let Some(rhs) = p.span_if(operand) {
+            let span = lhs.span.join(rhs.span);
+            let expr = Expr::Binary(ExprBinary {
+                lhs: Box::new(lhs),
+                op,
+                rhs: Box::new(rhs),
+            });
+            lhs = expr.span_with(span);
         } else {
             break;
         }
@@ -383,12 +352,8 @@ fn factor(p: &mut Parser) -> Option<Expr> {
     };
 
     if let Some(op) = p.span_if(|p| p.eat_map(op)) {
-        if let Some(expr) = p.span_if(factor) {
-            Some(Expr::Unary(ExprUnary { op, expr: Box::new(expr) }))
-        } else {
-            p.diag(error!(op.span, "missing factor"));
-            None
-        }
+        p.span_if(factor)
+            .map(|expr| Expr::Unary(ExprUnary { op, expr: Box::new(expr) }))
     } else {
         value(p)
     }
@@ -397,28 +362,28 @@ fn factor(p: &mut Parser) -> Option<Expr> {
 /// Parse a value.
 fn value(p: &mut Parser) -> Option<Expr> {
     let start = p.next_start();
-    Some(match p.eat()? {
+    Some(match p.eat() {
         // Bracketed function call.
-        Token::LeftBracket => {
+        Some(Token::LeftBracket) => {
             p.jump(start);
             let node = p.span(|p| SynNode::Expr(Expr::Call(bracket_call(p))));
             Expr::Lit(Lit::Content(vec![node]))
         }
 
         // Content expression.
-        Token::LeftBrace => {
+        Some(Token::LeftBrace) => {
             p.jump(start);
             Expr::Lit(Lit::Content(content(p)))
         }
 
         // Dictionary or just a parenthesized expression.
-        Token::LeftParen => {
+        Some(Token::LeftParen) => {
             p.jump(start);
             parenthesized(p)
         }
 
         // Function or just ident.
-        Token::Ident(id) => {
+        Some(Token::Ident(id)) => {
             let ident = Ident(id.into());
             let after = p.last_end();
             if p.peek() == Some(Token::LeftParen) {
@@ -429,24 +394,25 @@ fn value(p: &mut Parser) -> Option<Expr> {
             }
         }
 
-        // Atomic values.
-        Token::Bool(b) => Expr::Lit(Lit::Bool(b)),
-        Token::Int(i) => Expr::Lit(Lit::Int(i)),
-        Token::Float(f) => Expr::Lit(Lit::Float(f)),
-        Token::Length(val, unit) => Expr::Lit(Lit::Length(val, unit)),
-        Token::Percent(p) => Expr::Lit(Lit::Percent(p)),
-        Token::Hex(hex) => Expr::Lit(Lit::Color(color(p, hex, start))),
-        Token::Str(token) => Expr::Lit(Lit::Str(string(p, token))),
+        // Basic values.
+        Some(Token::Bool(b)) => Expr::Lit(Lit::Bool(b)),
+        Some(Token::Int(i)) => Expr::Lit(Lit::Int(i)),
+        Some(Token::Float(f)) => Expr::Lit(Lit::Float(f)),
+        Some(Token::Length(val, unit)) => Expr::Lit(Lit::Length(val, unit)),
+        Some(Token::Percent(p)) => Expr::Lit(Lit::Percent(p)),
+        Some(Token::Hex(hex)) => Expr::Lit(Lit::Color(color(p, hex, start))),
+        Some(Token::Str(token)) => Expr::Lit(Lit::Str(str(p, token))),
 
         // No value.
         _ => {
             p.jump(start);
+            p.diag_expected("expression");
             return None;
         }
     })
 }
 
-// Parse a content expression: `{...}`.
+// Parse a content value: `{...}`.
 fn content(p: &mut Parser) -> SynTree {
     p.push_mode(TokenMode::Body);
     p.start_group(Group::Brace);
@@ -487,7 +453,7 @@ fn color(p: &mut Parser, hex: &str, start: Pos) -> RgbaColor {
 }
 
 /// Parse a string.
-fn string(p: &mut Parser, token: TokenStr) -> String {
+fn str(p: &mut Parser, token: TokenStr) -> String {
     if !token.terminated {
         p.diag_expected_at("quote", p.last_end());
     }
diff --git a/src/parse/parser.rs b/src/parse/parser.rs
index 9f62175a..bf6eb76f 100644
--- a/src/parse/parser.rs
+++ b/src/parse/parser.rs
@@ -10,7 +10,9 @@ pub struct Parser<'s> {
     /// An iterator over the source tokens.
     tokens: Tokens<'s>,
     /// The next token.
-    /// (Only `None` if we are at the end of group or end of file).
+    next: Option<Token<'s>>,
+    /// The peeked token.
+    /// (Same as `next` except if we are at the end of group, then `None`).
     peeked: Option<Token<'s>>,
     /// The start position of the peeked token.
     next_start: Pos,
@@ -28,10 +30,11 @@ impl<'s> Parser<'s> {
     /// Create a new parser for the source string.
     pub fn new(src: &'s str) -> Self {
         let mut tokens = Tokens::new(src, TokenMode::Body);
-        let peeked = tokens.next();
+        let next = tokens.next();
         Self {
             tokens,
-            peeked,
+            next,
+            peeked: next,
             next_start: Pos::ZERO,
             last_end: Pos::ZERO,
             modes: vec![],
@@ -118,7 +121,9 @@ impl<'s> Parser<'s> {
             Group::Brace => self.eat_assert(Token::LeftBrace),
             Group::Subheader => {}
         }
+
         self.groups.push(group);
+        self.repeek();
     }
 
     /// Ends the parsing of a group and returns the span of the whole group.
@@ -130,6 +135,8 @@ impl<'s> Parser<'s> {
         debug_assert_eq!(self.peek(), None, "unfinished group");
 
         let group = self.groups.pop().expect("no started group");
+        self.repeek();
+
         let end = match group {
             Group::Paren => Some(Token::RightParen),
             Group::Bracket => Some(Token::RightBracket),
@@ -138,7 +145,7 @@ impl<'s> Parser<'s> {
         };
 
         if let Some(token) = end {
-            if self.peeked == Some(token) {
+            if self.next == Some(token) {
                 self.bump();
             } else {
                 self.diag(error!(self.next_start, "expected {}", token.name()));
@@ -203,26 +210,24 @@ impl<'s> Parser<'s> {
     }
 
     /// Peek at the next token without consuming it.
-    pub fn peek(&mut self) -> Option<Token<'s>> {
-        let group = match self.peeked {
-            Some(Token::RightParen) => Group::Paren,
-            Some(Token::RightBracket) => Group::Bracket,
-            Some(Token::RightBrace) => Group::Brace,
-            Some(Token::Pipe) => Group::Subheader,
-            other => return other,
-        };
-
-        if self.groups.contains(&group) {
-            return None;
-        }
-
+    pub fn peek(&self) -> Option<Token<'s>> {
         self.peeked
     }
 
+    /// Peek at the span of the next token.
+    ///
+    /// Has length zero if `peek()` returns `None`.
+    pub fn peek_span(&self) -> Span {
+        Span::new(
+            self.next_start,
+            if self.eof() { self.next_start } else { self.tokens.pos() },
+        )
+    }
+
     /// Checks whether the next token fulfills a condition.
     ///
     /// Returns `false` if there is no next token.
-    pub fn check<F>(&mut self, f: F) -> bool
+    pub fn check<F>(&self, f: F) -> bool
     where
         F: FnOnce(Token<'s>) -> bool,
     {
@@ -230,7 +235,7 @@ impl<'s> Parser<'s> {
     }
 
     /// Whether the end of the source string or group is reached.
-    pub fn eof(&mut self) -> bool {
+    pub fn eof(&self) -> bool {
         self.peek().is_none()
     }
 
@@ -284,22 +289,37 @@ impl<'s> Parser<'s> {
     fn bump(&mut self) {
         self.last_end = self.tokens.pos();
         self.next_start = self.tokens.pos();
-        self.peeked = self.tokens.next();
+        self.next = self.tokens.next();
 
         match self.tokens.mode() {
             TokenMode::Body => {}
             TokenMode::Header => {
                 while matches!(
-                    self.peeked,
+                    self.next,
                     Some(Token::Space(_)) |
                     Some(Token::LineComment(_)) |
                     Some(Token::BlockComment(_))
                 ) {
                     self.next_start = self.tokens.pos();
-                    self.peeked = self.tokens.next();
+                    self.next = self.tokens.next();
                 }
             }
         }
+
+        self.repeek();
+    }
+
+    fn repeek(&mut self) {
+        self.peeked = self.next;
+        if self.groups.contains(&match self.next {
+            Some(Token::RightParen) => Group::Paren,
+            Some(Token::RightBracket) => Group::Bracket,
+            Some(Token::RightBrace) => Group::Brace,
+            Some(Token::Pipe) => Group::Subheader,
+            _ => return,
+        }) {
+            self.peeked = None;
+        }
     }
 }
 
diff --git a/src/parse/resolve.rs b/src/parse/resolve.rs
index e908f22e..051bc7d5 100644
--- a/src/parse/resolve.rs
+++ b/src/parse/resolve.rs
@@ -18,7 +18,6 @@ pub fn resolve_string(string: &str) -> String {
         match s.eat() {
             Some('\\') => out.push('\\'),
             Some('"') => out.push('"'),
-
             Some('n') => out.push('\n'),
             Some('t') => out.push('\t'),
             Some('u') if s.eat_if('{') => {
@@ -29,7 +28,7 @@ pub fn resolve_string(string: &str) -> String {
                 if let Some(c) = resolve_hex(sequence) {
                     out.push(c);
                 } else {
-                    // TODO: Feedback that escape sequence is wrong.
+                    // TODO: Feedback that unicode escape sequence is wrong.
                     out += s.eaten_from(start);
                 }
             }
@@ -126,7 +125,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_unescape_strings() {
+    fn test_resolve_strings() {
         fn test(string: &str, expected: &str) {
             assert_eq!(resolve_string(string), expected.to_string());
         }
diff --git a/src/parse/tests.rs b/src/parse/tests.rs
index 632fe36e..230a5dba 100644
--- a/src/parse/tests.rs
+++ b/src/parse/tests.rs
@@ -1,57 +1,103 @@
-//! Parser tests.
-
 #![allow(non_snake_case)]
 
 use std::fmt::Debug;
 
 use super::parse;
 use crate::color::RgbaColor;
-use crate::diag::Deco;
+use crate::diag::{Diag, Level, Pass};
 use crate::eval::DictKey;
 use crate::geom::Unit;
 use crate::syntax::*;
 
-// ------------------------------ Construct Syntax Nodes ------------------------------ //
+use BinOp::*;
+use SynNode::{Emph, Linebreak, Parbreak, Space, Strong};
+use UnOp::*;
 
-use Deco::*;
-use SynNode::{Emph as E, Linebreak as L, Parbreak as P, Space as S, Strong as B};
+macro_rules! t {
+    ($src:literal
+        nodes: [$($node:expr),* $(,)?]
+        $(, errors: [$($err:expr),* $(,)?])?
+        $(, warnings: [$($warn:expr),* $(,)?])?
+        $(, spans: $spans:expr)?
+        $(,)?
+    ) => {{
+        #[allow(unused)]
+        let mut spans = false;
+        $(spans = $spans;)?
+
+        let Pass { output, feedback } = parse($src);
+        check($src, Content![@$($node),*], output, spans);
+        check(
+            $src,
+            vec![
+                $($(into!($err).map(|s: &str| Diag::new(Level::Error, s)),)*)?
+                $($(into!($warn).map(|s: &str| Diag::new(Level::Warning, s)),)*)?
+            ],
+            feedback.diags,
+            true,
+        );
+    }};
 
-fn T(text: &str) -> SynNode {
-    SynNode::Text(text.to_string())
+    ($src:literal $($node:expr),* $(,)?) => {
+        t!($src nodes: [$($node),*]);
+    };
 }
 
-macro_rules! H {
-    ($level:expr, $($tts:tt)*) => {
-        SynNode::Heading(NodeHeading {
-            level: Spanned::zero($level),
-            contents: Tree![@$($tts)*],
-        })
-    };
+/// Assert that expected and found are equal, printing both and the source of
+/// the test case if they aren't.
+///
+/// When `cmp_spans` is false, spans are ignored.
+#[track_caller]
+pub fn check<T>(src: &str, exp: T, found: T, cmp_spans: bool)
+where
+    T: Debug + PartialEq,
+{
+    Span::set_cmp(cmp_spans);
+
+    if exp != found {
+        println!("source:   {:?}", src);
+        println!("expected: {:#?}", exp);
+        println!("found:    {:#?}", found);
+        panic!("test failed");
+    }
+
+    Span::set_cmp(true);
 }
 
-macro_rules! R {
-    ($lang:expr, $inline:expr, $($line:expr),* $(,)?) => {{
-        SynNode::Raw(NodeRaw {
-            lang: $lang,
-            lines: vec![$($line.to_string()) ,*],
-            inline: $inline,
-        })
-    }};
+/// Shorthand for `Spanned::new`.
+fn S<T>(span: impl Into<Span>, v: T) -> Spanned<T> {
+    Spanned::new(v, span)
 }
 
-fn Lang(lang: &str) -> Option<Ident> {
-    Some(Ident(lang.to_string()))
+// Enables tests to optionally specify spans.
+impl<T> From<T> for Spanned<T> {
+    fn from(t: T) -> Self {
+        Spanned::zero(t)
+    }
 }
 
-macro_rules! F {
-    ($($tts:tt)*) => { SynNode::Expr(Expr::Call(Call!(@$($tts)*))) }
+/// Shorthand for `Into::<Spanned<_>>::into`.
+macro_rules! into {
+    ($val:expr) => {
+        Into::<Spanned<_>>::into($val)
+    };
 }
 
-// ------------------------------- Construct Expressions ------------------------------ //
+fn Text(text: &str) -> SynNode {
+    SynNode::Text(text.into())
+}
 
-use BinOp::*;
-use UnOp::*;
-use Unit::*;
+fn Heading(level: impl Into<Spanned<u8>>, contents: SynTree) -> SynNode {
+    SynNode::Heading(NodeHeading { level: level.into(), contents })
+}
+
+fn Raw(lang: Option<&str>, lines: &[&str], inline: bool) -> SynNode {
+    SynNode::Raw(NodeRaw {
+        lang: lang.map(|id| Ident(id.into())),
+        lines: lines.iter().map(ToString::to_string).collect(),
+        inline,
+    })
+}
 
 fn Id(ident: &str) -> Expr {
     Expr::Lit(Lit::Ident(Ident(ident.to_string())))
@@ -85,30 +131,13 @@ fn Str(string: &str) -> Expr {
     Expr::Lit(Lit::Str(string.to_string()))
 }
 
-macro_rules! Call {
-    (@$name:expr $(, $span:expr)? $(; $($tts:tt)*)?) => {{
-        let name = Into::<Spanned<&str>>::into($name);
-        #[allow(unused)]
-        let mut span = Span::ZERO;
-        $(span = $span.into();)?
-        ExprCall {
-            name: name.map(|n| Ident(n.to_string())),
-            args: Dict![@$($($tts)*)?].span_with(span),
-        }
-    }};
-    ($($tts:tt)*) => { Expr::Call(Call![@$($tts)*]) };
-}
-
-fn Unary(op: impl Into<Spanned<UnOp>>, expr: impl Into<Spanned<Expr>>) -> Expr {
-    Expr::Unary(ExprUnary {
-        op: op.into(),
-        expr: Box::new(expr.into()),
-    })
+fn Block(expr: Expr) -> SynNode {
+    SynNode::Expr(expr)
 }
 
 fn Binary(
-    op: impl Into<Spanned<BinOp>>,
     lhs: impl Into<Spanned<Expr>>,
+    op: impl Into<Spanned<BinOp>>,
     rhs: impl Into<Spanned<Expr>>,
 ) -> Expr {
     Expr::Binary(ExprBinary {
@@ -118,463 +147,418 @@ fn Binary(
     })
 }
 
-macro_rules! Dict {
-    (@dict=$dict:expr,) => {};
-    (@dict=$dict:expr, $key:expr => $expr:expr $(, $($tts:tt)*)?) => {{
-        let key = Into::<Spanned<&str>>::into($key);
-        let key = key.map(Into::<DictKey>::into);
-        let expr = Into::<Spanned<Expr>>::into($expr);
-        $dict.0.push(LitDictEntry { key: Some(key), expr });
-        Dict![@dict=$dict, $($($tts)*)?];
-    }};
-    (@dict=$dict:expr, $expr:expr $(, $($tts:tt)*)?) => {
-        let expr = Into::<Spanned<Expr>>::into($expr);
-        $dict.0.push(LitDictEntry { key: None, expr });
-        Dict![@dict=$dict, $($($tts)*)?];
-    };
-    (@$($tts:tt)*) => {{
-        #[allow(unused)]
-        let mut dict = LitDict::new();
-        Dict![@dict=dict, $($tts)*];
-        dict
-    }};
-    ($($tts:tt)*) => { Expr::Lit(Lit::Dict(Dict![@$($tts)*])) };
-}
-
-macro_rules! Tree {
-    (@$($node:expr),* $(,)?) => {
-        vec![$(Into::<Spanned<SynNode>>::into($node)),*]
-    };
-    ($($tts:tt)*) => { Expr::Lit(Lit::Content(Tree![@$($tts)*])) };
+fn Unary(op: impl Into<Spanned<UnOp>>, expr: impl Into<Spanned<Expr>>) -> Expr {
+    Expr::Unary(ExprUnary {
+        op: op.into(),
+        expr: Box::new(expr.into()),
+    })
 }
 
-// ------------------------------------ Test Macros ----------------------------------- //
-
-// Test syntax trees with or without spans.
-macro_rules! t { ($($tts:tt)*) => {test!(@spans=false, $($tts)*)} }
-macro_rules! ts { ($($tts:tt)*) => {test!(@spans=true, $($tts)*)} }
-macro_rules! test {
-    (@spans=$spans:expr, $src:expr => $($tts:tt)*) => {
-        let exp = Tree![@$($tts)*];
-        let pass = parse($src);
-        check($src, exp, pass.output, $spans);
+macro_rules! Dict {
+    (@$($a:expr $(=> $b:expr)?),* $(,)?) => {
+        LitDict(vec![$(#[allow(unused)] {
+            let key: Option<Spanned<DictKey>> = None;
+            let expr = $a;
+            $(
+                let key = Some(into!($a).map(|s: &str| s.into()));
+                let expr = $b;
+            )?
+            LitDictEntry { key, expr: into!(expr) }
+        }),*])
     };
+    ($($tts:tt)*) => (Expr::Lit(Lit::Dict(Dict![@$($tts)*])));
 }
 
-// Test expressions.
-macro_rules! v {
-    ($src:expr => $($tts:tt)*) => {
-        t!(concat!("[val ", $src, "]") => F!("val"; $($tts)*));
-    }
-}
-
-// Test error messages.
-macro_rules! e {
-    ($src:expr => $($tts:tt)*) => {
-        let exp = vec![$($tts)*];
-        let pass = parse($src);
-        let found = pass.feedback.diags.iter()
-            .map(|s| s.as_ref().map(|e| e.message.as_str()))
-            .collect::<Vec<_>>();
-        check($src, exp, found, true);
-    };
+macro_rules! Content {
+    (@$($node:expr),* $(,)?) => (vec![$(into!($node)),*]);
+    ($($tts:tt)*) => (Expr::Lit(Lit::Content(Content![@$($tts)*])));
 }
 
-// Test decorations.
-macro_rules! d {
-    ($src:expr => $($tts:tt)*) => {
-        let exp = vec![$($tts)*];
-        let pass = parse($src);
-        check($src, exp, pass.feedback.decos, true);
+macro_rules! Call {
+    (@@$name:expr) => {
+        Call!(@@$name, Args![])
     };
-}
-
-/// Assert that expected and found are equal, printing both and panicking
-/// and the source of their test case if they aren't.
-///
-/// When `cmp_spans` is false, spans are ignored.
-#[track_caller]
-pub fn check<T>(src: &str, exp: T, found: T, cmp_spans: bool)
-where
-    T: Debug + PartialEq,
-{
-    Span::set_cmp(cmp_spans);
-    let equal = exp == found;
-    Span::set_cmp(true);
-
-    if !equal {
-        println!("source:   {:?}", src);
-        if cmp_spans {
-            println!("expected: {:#?}", exp);
-            println!("found:    {:#?}", found);
-        } else {
-            println!("expected: {:?}", exp);
-            println!("found:    {:?}", found);
+    (@@$name:expr, $args:expr) => {
+        ExprCall {
+            name: into!($name).map(|s: &str| Ident(s.into())),
+            args: into!($args),
         }
-        panic!("test failed");
-    }
+    };
+    (@$($tts:tt)*) => (Expr::Call(Call!(@@$($tts)*)));
+    ($($tts:tt)*) => (SynNode::Expr(Call!(@$($tts)*)));
 }
 
-pub fn s<T>(start: u32, end: u32, v: T) -> Spanned<T> {
-    v.span_with(Span::new(start, end))
+macro_rules! Args {
+    ($($tts:tt)*) => (Dict![@$($tts)*]);
 }
 
-// Enables tests to optionally specify spans.
-impl<T> From<T> for Spanned<T> {
-    fn from(t: T) -> Self {
-        Spanned::zero(t)
-    }
-}
-
-// --------------------------------------- Tests -------------------------------------- //
-
 #[test]
-fn test_parse_groups() {
-    e!("[)" => s(1, 2, "expected function name, found closing paren"),
-               s(2, 2, "expected closing bracket"));
+fn test_parse_comments() {
+    // In body.
+    t!("a// you\nb"        Text("a"), Space, Text("b"));
+    t!("* // \n /*\n\n*/*" Strong, Space, Space, Strong);
 
-    e!("[v {]}" => s(4, 4, "expected closing brace"),
-                   s(5, 6, "unexpected closing brace"));
-}
+    // In header.
+    t!("[v /*12pt*/]"            Call!("v"));
+    t!("[v //\n]"                Call!("v"));
+    t!("[v 12, /*\n*/ size: 14]" Call!("v", Args![Int(12), "size" => Int(14)]));
 
-#[test]
-fn test_parse_simple_nodes() {
-    t!(""               => );
-    t!("hi"             => T("hi"));
-    t!("*hi"            => B, T("hi"));
-    t!("hi_"            => T("hi"), E);
-    t!("hi you"         => T("hi"), S, T("you"));
-    t!("special~name"   => T("special"), T("\u{00A0}"), T("name"));
-    t!("special\\~name" => T("special"), T("~"), T("name"));
-    t!("\\u{1f303}"     => T("🌃"));
-    t!("\n\n\nhello"    => P, T("hello"));
-    t!(r"a\ b"          => T("a"), L, S, T("b"));
-
-    e!("\\u{d421c809}" => s(0, 12, "invalid unicode escape sequence"));
-    e!("\\u{abc"       => s(6, 6, "expected closing brace"));
-    t!("💜\n\n 🌍"    => T("💜"), P, T("🌍"));
-
-    ts!("hi"   => s(0, 2, T("hi")));
-    ts!("*Hi*" => s(0, 1, B), s(1, 3, T("Hi")), s(3, 4, B));
-    ts!("💜\n\n 🌍" => s(0, 4, T("💜")), s(4, 7, P), s(7, 11, T("🌍")));
+    // Error.
+    t!("a*/b"
+        nodes: [Text("a"), Text("b")],
+        errors: [S(1..3, "unexpected end of block comment")]);
 }
 
 #[test]
-fn test_parse_raw() {
-    t!("`py`"            => R![None, true, "py"]);
-    t!("`hi\nyou"        => R![None, true, "hi", "you"]);
-    t!(r"`` hi\`du``"    => R![None, true, r"hi\`du"]);
-
-    // More than one backtick with optional language tag.
-    t!("``` console.log(\n\"alert\"\n)" => R![None, false, "console.log(", "\"alert\"", ")"]);
-    t!("````typst \r\n Typst uses ``` to indicate code blocks````!"
-        => R![Lang("typst"), false, " Typst uses ``` to indicate code blocks"], T("!"));
-
-    // Trimming of whitespace.
-    t!("`` a ``"         => R![None, true, "a"]);
-    t!("`` a  ``"        => R![None, true, "a "]);
-    t!("`` ` ``"         => R![None, true, "`"]);
-    t!("```  `   ```"    => R![None, true, " `  "]);
-    t!("```  `   \n ```" => R![None, false, " `   "]);
+fn test_parse_simple_nodes() {
+    // Basics.
+    t!("");
+    t!(" "    Space);
+    t!("hi"   Text("hi"));
+    t!("🧽"   Text("🧽"));
+    t!("_"    Emph);
+    t!("*"    Strong);
+    t!("~"    Text("\u{00A0}"));
+    t!(r"\"   Linebreak);
+    t!("\n\n" Parbreak);
+
+    // Multiple nodes.
+    t!("ab c"         Text("ab"), Space, Text("c"));
+    t!("a`hi`\r\n\r*" Text("a"), Raw(None, &["hi"], true), Parbreak, Strong);
+
+    // Spans.
+    t!("*🌍*"
+        nodes: [S(0..1, Strong), S(1..5, Text("🌍")), S(5..6, Strong)],
+        spans: true);
 
     // Errors.
-    e!("`hi\nyou"         => s(7, 7, "expected backtick(s)"));
-    e!("``` hi\nyou"      => s(10, 10, "expected backtick(s)"));
-
-    // TODO: Bring back when spans/errors are in place.
-    // ts!("``java out``" => s(0, 12, R![Lang(s(2, 6, "java")), true, "out"]));
-    // e!("```🌍 hi\nyou```" => s(3, 7, "invalid identifier"));
+    t!("]}"
+        nodes: [],
+        errors: [S(0..1, "unexpected closing bracket"),
+                 S(1..2, "unexpected closing brace")]);
 }
 
 #[test]
-fn test_parse_comments() {
-    // In body.
-    t!("hi// you\nw"          => T("hi"), S, T("w"));
-    t!("first//\n//\nsecond"  => T("first"), S, S, T("second"));
-    t!("first//\n \nsecond"   => T("first"), P, T("second"));
-    t!("first/*\n \n*/second" => T("first"), T("second"));
-    e!("🌎\n*/n" => s(5, 7, "unexpected end of block comment"));
+fn test_parse_headings() {
+    // Basics with spans.
+    t!("#a"
+        nodes: [S(0..2, Heading(S(0..1, 0), Content![@S(1..2, Text("a"))]))],
+        spans: true);
+
+    // Multiple hashtags.
+    t!("###three"   Heading(2, Content![@Text("three")]));
+    t!("###### six" Heading(5, Content![@Space, Text("six")]));
+
+    // Start of heading.
+    t!("/**/#"    Heading(0, Content![@]));
+    t!("[f][#ok]" Call!("f", Args![Content![Heading(0, Content![@Text("ok")])]]));
+
+    // End of heading.
+    t!("#a\nb" Heading(0, Content![@Text("a")]), Space, Text("b"));
+
+    // Continued heading.
+    t!("#a{\n1\n}b"   Heading(0, Content![@Text("a"), Block(Int(1)), Text("b")]));
+    t!("#a[f][\n\n]d" Heading(0, Content![@
+        Text("a"), Call!("f", Args![Content![Parbreak]]), Text("d"),
+    ]));
 
-    // In header.
-    t!("[val /*12pt*/]"        => F!("val"));
-    t!("[val \n /* \n */]"     => F!("val"));
-    e!("[val \n /* \n */]"     => );
-    e!("[val 12, /* \n */ 14]" => );
+    // No heading.
+    t!(r"\#"    Text("#"));
+    t!("Nr. #1" Text("Nr."), Space, Text("#"), Text("1"));
+    t!("[v]#"   Call!("v"), Text("#"));
+
+    // Too many hashtags.
+    t!("####### seven"
+        nodes: [Heading(5, Content![@Space, Text("seven")])],
+        warnings: [S(0..7, "section depth should not exceed 6")]);
 }
 
 #[test]
-fn test_parse_headings() {
-    t!("## Hello world!" => H![1, S, T("Hello"), S, T("world!")]);
-
-    // Handle various whitespace usages.
-    t!("####Simple"                         => H![3, T("Simple")]);
-    t!("  #    Whitespace!"                 => S, H![0, S, T("Whitespace!")]);
-    t!("  /* TODO: Improve */  ## Analysis" => S, S, H!(1, S, T("Analysis")));
-    t!("# Heading \n ends"                  => H![0, S, T("Heading")], S, T("ends"));
-
-    // Complex heading contents.
-    t!("Some text [box][### Valuable facts]" => T("Some"), S, T("text"), S,
-        F!("box"; Tree![H!(2, S, T("Valuable"), S, T("facts"))])
-    );
-    t!("### Grandiose stuff [box][Get it \n\n straight]" => H![
-        2,
-        S, T("Grandiose"), S, T("stuff"), S,
-        F!("box"; Tree![T("Get"), S, T("it"), P, T("straight")])
-    ]);
-    t!("###### Multiline \\ headings" => H![5, S, T("Multiline"), S, L, S, T("headings")]);
-
-    // Things that should not become headings.
-    t!("\\## Text"      => T("#"), T("#"), S, T("Text"));
-    t!(" ###### # Text" => S, H![5, S, T("#"), S, T("Text")]);
-    t!("I am #1"        => T("I"), S, T("am"), S, T("#"), T("1"));
-    t!("[box][\n] # hi" => F!("box"; Tree![S]), S, T("#"), S, T("hi"));
-
-    // Depth warnings.
-    e!("########" => s(0, 8, "section depth should be at most 6"));
+fn test_parse_raw() {
+    // Basic, mostly tested in tokenizer and resolver.
+    t!("`py`" nodes: [S(0..4, Raw(None, &["py"], true))], spans: true);
+    t!("`endless"
+        nodes: [Raw(None, &["endless"], true)],
+        errors: [S(8..8, "expected backtick(s)")]);
 }
 
 #[test]
-fn test_parse_function_names() {
-    // No closing bracket.
-    t!("[" => F!(""));
-    e!("[" => s(1, 1, "expected function name"),
-              s(1, 1, "expected closing bracket"));
-
-    // No name.
-    e!("[]"   => s(1, 1, "expected function name"));
-    e!("[\"]" => s(1, 3, "expected function name, found string"),
-                 s(3, 3, "expected closing bracket"));
+fn test_parse_escape_sequences() {
+    // Basic, mostly tested in tokenizer.
+    t!(r"\[" Text("["));
+    t!(r"\u{1F3D5}" nodes: [S(0..9, Text("🏕"))], spans: true);
 
-    // A valid name.
-    t!("[hi]"  => F!("hi"));
-    t!("[  f]" => F!("f"));
+    // Bad value.
+    t!(r"\u{FFFFFF}"
+        nodes: [Text(r"\u{FFFFFF}")],
+        errors: [S(0..10, "invalid unicode escape sequence")]);
 
-    // An invalid name.
-    e!("[12]"   => s(1, 3, "expected function name, found integer"));
-    e!("[  🌎]" => s(3, 7, "expected function name, found invalid token"));
+    // No closing brace.
+    t!(r"\u{41*"
+        nodes: [Text("A"), Strong],
+        errors: [S(5..5, "expected closing brace")]);
 }
 
 #[test]
-fn test_parse_chaining() {
-    // Things the parser has to make sense of
-    t!("[hi (5.0, 2.1 | you]" => F!("hi"; Dict![Float(5.0), Float(2.1)], Tree![F!("you")]));
-    t!("[box | pad: 1pt][Hi]"  => F!("box"; Tree![
-        F!("pad"; Length(1.0, Pt), Tree!(T("Hi")))
-    ]));
-    t!("[bold 400, | emph | sub: 1cm]" => F!("bold"; Int(400), Tree![
-        F!("emph"; Tree!(F!("sub"; Length(1.0, Cm))))
-    ]));
-
-    // Errors for unclosed / empty predecessor groups
-    e!("[hi (5.0, 2.1 | you]" => s(14, 14, "expected closing paren"));
-    e!("[| abc]"              => s(1, 1, "expected function name"));
-    e!("[box |][Hi]"          => s(6, 6, "expected function name"));
+fn test_parse_groups() {
+    // Test paren group.
+    t!("{([v 1) + 3}"
+        nodes: [Block(Binary(
+            Content![Call!("v", Args![Int(1)])],
+            Add,
+            Int(3),
+        ))],
+        errors: [S(6..6, "expected closing bracket")]);
+
+    // Test bracket group.
+    t!("[)"
+        nodes: [Call!("")],
+        errors: [S(1..2, "expected function name, found closing paren"),
+                 S(2..2, "expected closing bracket")]);
+
+    t!("[v {]}"
+        nodes: [Call!("v", Args![Content![]])],
+        errors: [S(4..4, "expected closing brace"),
+                 S(5..6, "unexpected closing brace")]);
+
+    // Test brace group.
+    t!("{1 + [}"
+        nodes: [Block(Binary(Int(1), Add, Content![Call!("")]))],
+        errors: [S(6..6, "expected function name"),
+                 S(6..6, "expected closing bracket")]);
+
+    // Test subheader group.
+    t!("[v (|u )]"
+        nodes: [Call!("v", Args![Dict![], Content![Call!("u")]])],
+        errors: [S(4..4, "expected closing paren"),
+                 S(7..8, "expected expression, found closing paren")]);
 }
 
 #[test]
-fn test_parse_function_bodies() {
-    t!("[val 1][*Hi*]" => F!("val"; Int(1), Tree![B, T("Hi"), B]));
-    e!(" [val][ */]"    => s(8, 10, "unexpected end of block comment"));
-
-    // Raw in body.
-    t!("[val][`Hi]`" => F!("val"; Tree![R![None, true, "Hi]"]]));
-    e!("[val][`Hi]`" => s(11, 11, "expected closing bracket"));
+fn test_parse_blocks() {
+    // Basic with spans.
+    t!("{1}" nodes: [S(0..3, Block(Int(1)))], spans: true);
 
-    // Crazy.
-    t!("[v][[v][v][v]]" => F!("v"; Tree![F!("v"; Tree![T("v")]), F!("v")]));
+    // Function calls.
+    t!("{f()}" Call!("f"));
+    t!("{[f]}" Block(Content![Call!("f")]));
 
-    // Spanned.
-    ts!(" [box][Oh my]" =>
-        s(0, 1, S),
-        s(1, 13, F!(s(2, 5, "box"), 5 .. 5;
-            s(6, 13, Tree![
-                s(7, 9, T("Oh")), s(9, 10, S), s(10, 12, T("my")),
-            ])
-        ))
-    );
+    // Missing or bad value.
+    t!("{}{1u}"
+        nodes: [],
+        errors: [S(1..1, "expected expression"),
+                 S(3..5, "expected expression, found invalid token")]);
 }
 
 #[test]
-fn test_parse_values() {
-    // Simple.
-    v!("_"         => Id("_"));
-    v!("name"      => Id("name"));
-    v!("ke-bab"    => Id("ke-bab"));
-    v!("α"         => Id("α"));
-    v!("\"hi\""    => Str("hi"));
-    v!("true"      => Bool(true));
-    v!("false"     => Bool(false));
-    v!("1.0e-4"    => Float(1e-4));
-    v!("3.15"      => Float(3.15));
-    v!("50%"       => Percent(50.0));
-    v!("4.5cm"     => Length(4.5, Cm));
-    v!("12e1pt"    => Length(12e1, Pt));
-    v!("#f7a20500" => Color(RgbaColor::new(0xf7, 0xa2, 0x05, 0x00)));
-    v!("\"a\n[]\\\"string\"" => Str("a\n[]\"string"));
-
-    // Content.
-    v!("{_hi_}"        => Tree![E, T("hi"), E]);
-    e!("[val {_hi_}]" => );
-    v!("[hi]"          => Tree![F!("hi")]);
-    e!("[val [hi]]"   => );
-
-    // Healed colors.
-    v!("#12345"            => Color(RgbaColor::new(0, 0, 0, 0xff)));
-    e!("[val #12345]"     => s(5, 11, "invalid color"));
-    e!("[val #a5]"        => s(5, 8,  "invalid color"));
-    e!("[val #14b2ah]"    => s(5, 12, "invalid color"));
-    e!("[val #f075ff011]" => s(5, 15, "invalid color"));
-
-    // Unclosed string.
-    v!("\"hello"        => Str("hello]"));
-    e!("[val \"hello]" => s(12, 12, "expected quote"),
-                          s(12, 12, "expected closing bracket"));
-
-    // Spanned.
-    ts!("[val 1.4]" => s(0, 9, F!(s(1, 4, "val"), 5 .. 8; s(5, 8, Float(1.4)))));
-}
+fn test_parse_bracket_funcs() {
+    // Basic.
+    t!("[function]" Call!("function"));
+    t!("[ v ]"      Call!("v"));
+
+    // Body and no body.
+    t!("[v][[f]]"  Call!("v", Args![Content![Call!("f")]]));
+    t!("[v][v][v]" Call!("v", Args![Content![Text("v")]]), Call!("v"));
+    t!("[v] [f]"   Call!("v"), Space, Call!("f"));
+
+    // Spans.
+    t!("[v 1][📐]"
+        nodes: [S(0..11, Call!(S(1..2, "v"), S(3..4, Args![
+            S(3..4, Int(1)),
+            S(5..11, Content![S(6..10, Text("📐"))]),
+        ])))],
+        spans: true);
+
+    // No name and no closing bracket.
+    t!("["
+        nodes: [Call!("")],
+        errors: [S(1..1, "expected function name"),
+                 S(1..1, "expected closing bracket")]);
 
-#[test]
-fn test_parse_expressions() {
-    // Coerced dict.
-    v!("(hi)" => Id("hi"));
-
-    // Operations.
-    v!("-1"          => Unary(Neg, Int(1)));
-    v!("-- 1"        => Unary(Neg, Unary(Neg, Int(1))));
-    v!("--css"       => Unary(Neg, Unary(Neg, Id("css"))));
-    v!("3.2in + 6pt" => Binary(Add, Length(3.2, In), Length(6.0, Pt)));
-    v!("5 - 0.01"    => Binary(Sub, Int(5), Float(0.01)));
-    v!("(3mm * 2)"   => Binary(Mul, Length(3.0, Mm), Int(2)));
-    v!("12e-3cm/1pt" => Binary(Div, Length(12e-3, Cm), Length(1.0, Pt)));
-
-    // More complex.
-    v!("(3.2in + 6pt)*(5/2-1)" => Binary(
-        Mul,
-        Binary(Add, Length(3.2, In), Length(6.0, Pt)),
-        Binary(Sub, Binary(Div, Int(5), Int(2)), Int(1))
-    ));
-    v!("(6.3E+2+4* - 3.2pt)/2" => Binary(
-        Div,
-        Binary(Add, Float(6.3e2), Binary(
-            Mul,
-            Int(4),
-            Unary(Neg, Length(3.2, Pt))
-        )),
-        Int(2)
-    ));
-
-    // Associativity of multiplication and division.
-    v!("3/4*5" => Binary(Mul, Binary(Div, Int(3), Int(4)), Int(5)));
-
-    // Spanned.
-    ts!("[val 1 + 3]" => s(0, 11, F!(
-        s(1, 4, "val"), 5 .. 10; s(5, 10, Binary(
-            s(7, 8, Add),
-            s(5, 6, Int(1)),
-            s(9, 10, Int(3))
-        ))
-    )));
+    // No name.
+    t!("[]"
+        nodes: [Call!("")],
+        errors: [S(1..1, "expected function name")]);
 
-    // Span of parenthesized expression contains parens.
-    ts!("[val (1)]" => s(0, 9, F!(s(1, 4, "val"), 5 .. 8; s(5, 8, Int(1)))));
+    // Bad name.
+    t!("[# 1]"
+        nodes: [Call!("", Args![Int(1)])],
+        errors: [S(1..2, "expected function name, found hex value")]);
 
-    // Invalid expressions.
-    v!("4pt--"       => Length(4.0, Pt));
-    e!("[val 4pt--]" => s(9, 10, "missing factor"),
-                        s(5, 9, "missing right summand"));
+    // String header eats closing bracket.
+    t!(r#"[v "]"#
+        nodes: [Call!("v", Args![Str("]")])],
+        errors: [S(5..5, "expected quote"),
+                 S(5..5, "expected closing bracket")]);
 
-    v!("3mm+4pt*"       => Binary(Add, Length(3.0, Mm), Length(4.0, Pt)));
-    e!("[val 3mm+4pt*]" => s(9, 13, "missing right factor"));
+    // Raw in body eats closing bracket.
+    t!("[v][`a]`"
+        nodes: [Call!("v", Args![Content![Raw(None, &["a]"], true)]])],
+        errors: [S(8..8, "expected closing bracket")]);
 }
 
 #[test]
-fn test_parse_dicts() {
-    // Okay.
-    v!("()"                 => Dict![]);
-    v!("(false)"            => Bool(false));
-    v!("(true,)"            => Dict![Bool(true)]);
-    v!("(key: val)"          => Dict!["key" => Id("val")]);
-    v!("(1, 2)"             => Dict![Int(1), Int(2)]);
-    v!("(1, key: \"value\")" => Dict![Int(1), "key" => Str("value")]);
-
-    // Decorations.
-    d!("[val key: hi]"    => s(5, 8, DictKey));
-    d!("[val (key: hi)]"  => s(6, 9, DictKey));
-    d!("[val f(key: hi)]" => s(7, 10, DictKey));
-
-    // Spanned with spacing around named arguments.
-    ts!("[val  \n hi \n : /* //\n */ \"s\n\"]" => s(0, 30, F!(
-        s(1, 4, "val"),
-        8 .. 29; s(8, 10, "hi") => s(25, 29, Str("s\n"))
-    )));
-    e!("[val  \n hi \n : /* //\n */ \"s\n\"]" => );
+fn test_parse_chaining() {
+    // Basic.
+    t!("[a | b]"     Call!("a", Args![Content![Call!("b")]]));
+    t!("[a | b | c]" Call!("a", Args![Content![
+        Call!("b", Args![Content![Call!("c")]])
+    ]]));
+
+    // With body and spans.
+    t!("[a|b][💕]"
+        nodes: [S(0..11, Call!(S(1..2, "a"), S(2..2, Args![
+            S(3..11, Content![S(3..11, Call!(S(3..4, "b"), S(4..4, Args![
+                S(5..11, Content![S(6..10, Text("💕"))])
+            ])))])
+        ])))],
+        spans: true);
+
+    // No name in second subheader.
+    t!("[a 1|]"
+        nodes: [Call!("a", Args![Int(1), Content![Call!("")]])],
+        errors: [S(5..5, "expected function name")]);
+
+    // No name in first subheader.
+    t!("[|a true]"
+        nodes: [Call!("", Args![Content![Call!("a", Args![Bool(true)])]])],
+        errors: [S(1..1, "expected function name")]);
 }
 
 #[test]
-fn test_parse_dicts_paren_func_calls() {
-    v!("empty()"                  => Call!("empty"));
-    v!("add ( 1 , 2 )"            => Call!("add"; Int(1), Int(2)));
-    v!("items(\"fire\", #f93a6d)" => Call!("items";
-        Str("fire"), Color(RgbaColor::new(0xf9, 0x3a, 0x6d, 0xff))
-    ));
-
-    // More complex.
-    v!(r#"css(1pt, color: rgb(90, 102, 254), stroke: "solid")"# => Call!(
-        "css";
-        Length(1.0, Pt),
-        "color" => Call!("rgb"; Int(90), Int(102), Int(254)),
-        "stroke" => Str("solid"),
-    ));
+fn test_parse_arguments() {
+    // Bracket functions.
+    t!("[v 1]"   Call!("v", Args![Int(1)]));
+    t!("[v 1,]"  Call!("v", Args![Int(1)]));
+    t!("[v a]"   Call!("v", Args![Id("a")]));
+    t!("[v a,]"  Call!("v", Args![Id("a")]));
+    t!("[v a:2]" Call!("v", Args!["a" => Int(2)]));
+
+    // Parenthesized function with nested dictionary literal.
+    t!(r#"{f(1, a: (2, 3), #004, b: "five")}"# Block(Call!(@"f", Args![
+        Int(1),
+        "a" => Dict![Int(2), Int(3)],
+        Color(RgbaColor::new(0, 0, 0x44, 0xff)),
+        "b" => Str("five"),
+    ])));
+
+    // Bad expression.
+    t!("[v */]"
+        nodes: [Call!("v", Args![])],
+        errors: [S(3..5, "expected expression, found end of block comment")]);
+
+    // Missing comma between arguments.
+    t!("[v 1 2]"
+        nodes: [Call!("v", Args![Int(1), Int(2)])],
+        errors: [S(4..4, "expected comma")]);
+
+    // Missing expression after name.
+    t!("[v a:]"
+        nodes: [Call!("v", Args![])],
+        errors: [S(5..5, "expected expression")]);
+
+    // Bad expression after name.
+    t!("[v a:1:]"
+        nodes: [Call!("v", Args!["a" => Int(1)])],
+        errors: [S(6..7, "expected expression, found colon")]);
+
+    // Name has to be identifier. Number parsed as positional argument.
+    t!("[v 1:]"
+        nodes: [Call!("v", Args![Int(1)])],
+        errors: [S(4..5, "expected expression, found colon")]);
+
+    // Parsed as two positional arguments.
+    t!("[v 1:2]"
+        nodes: [Call!("v", Args![Int(1), Int(2)])],
+        errors: [S(4..5, "expected expression, found colon"),
+                 S(4..4, "expected comma")]);
+}
 
-    // Unclosed.
-    v!("lang(中文]"      => Call!("lang"; Id("中文")));
-    e!("[val lang(中文]" => s(16, 16, "expected closing paren"));
+#[test]
+fn test_parse_dict_literals() {
+    // Basic.
+    t!("{()}" Block(Dict![]));
+
+    // With spans.
+    t!("{(1, two: 2)}"
+        nodes: [S(0..13, Block(Dict![
+            S(2..3, Int(1)),
+            S(5..8, "two") => S(10..11, Int(2)),
+        ]))],
+        spans: true);
 
-    // Invalid name.
-    v!("👠(\"abc\", 13e-5)"       => Dict!(Str("abc"), Float(13.0e-5)));
-    e!("[val 👠(\"abc\", 13e-5)]" => s(5, 9, "invalid token"));
+    // Unclosed.
+    t!("{(}"
+        nodes: [Block(Dict![])],
+        errors: [S(2..2, "expected closing paren")]);
 }
 
 #[test]
-fn test_parse_dicts_nested() {
-    v!("(1, ( ab:(), d : (3, 14pt) )), false" =>
-        Dict![
-            Int(1),
-            Dict!(
-                "ab" => Dict![],
-                "d"  => Dict!(Int(3), Length(14.0, Pt)),
-            ),
-        ],
-        Bool(false),
-    );
+fn test_parse_expressions() {
+    // Parenthesis.
+    t!("{(x)}" Block(Id("x")));
+
+    // Unary operations.
+    t!("{-1}"  Block(Unary(Neg, Int(1))));
+    t!("{--1}" Block(Unary(Neg, Unary(Neg, Int(1)))));
+
+    // Binary operations.
+    t!(r#"{"x"+"y"}"# Block(Binary(Str("x"), Add, Str("y"))));
+    t!("{1-2}"        Block(Binary(Int(1), Sub, Int(2))));
+    t!("{a * b}"      Block(Binary(Id("a"), Mul, Id("b"))));
+    t!("{12pt/.4}"    Block(Binary(Length(12.0, Unit::Pt), Div, Float(0.4))));
+
+    // Associativity.
+    t!("{1+2+3}" Block(Binary(Binary(Int(1), Add, Int(2)), Add, Int(3))));
+    t!("{1/2*3}" Block(Binary(Binary(Int(1), Div, Int(2)), Mul, Int(3))));
+
+    // Precedence.
+    t!("{1+2*-3}" Block(Binary(
+        Int(1), Add, Binary(Int(2), Mul, Unary(Neg, Int(3))),
+    )));
+
+    // Confusion with floating-point literal.
+    t!("{1e-3-4e+4}" Block(Binary(Float(1e-3), Sub, Float(4e+4))));
+
+    // Spans + parentheses winning over precedence.
+    t!("{(1+2)*3}"
+        nodes: [S(0..9, Block(Binary(
+            S(1..6, Binary(S(2..3, Int(1)), S(3..4, Add), S(4..5, Int(2)))),
+            S(6..7, Mul),
+            S(7..8, Int(3)),
+        )))],
+        spans: true);
+
+    // Errors.
+    t!("{-}{1+}{2*}"
+        nodes: [Block(Int(1)), Block(Int(2))],
+        errors: [S(2..2, "expected expression"),
+                 S(6..6, "expected expression"),
+                 S(10..10, "expected expression")]);
 }
 
 #[test]
-fn test_parse_dicts_errors() {
-    // Expected value.
-    e!("[val (:)]"         => s(6, 7, "unexpected colon"));
-    e!("[val (,)]"         => s(6, 7, "unexpected comma"));
-    v!("(\x07 abc,)"       => Dict![Id("abc")]);
-    e!("[val (\x07 abc,)]" => s(6, 7, "invalid token"));
-    e!("[val (key:,)]"     => s(10, 11, "expected value, found comma"));
-    e!("[val hi,)]"        => s(8, 9, "unexpected closing paren"));
-
-    // Expected comma.
-    v!("(true false)"       => Dict![Bool(true), Bool(false)]);
-    e!("[val (true false)]" => s(10, 10, "expected comma"));
-
-    // Expected closing paren.
-    e!("[val (#000]" => s(10, 10, "expected closing paren"));
-    e!("[val (key]"  => s(9, 9, "expected closing paren"));
-    e!("[val (key:]" => s(10, 10, "expected value"),
-                        s(10, 10, "expected closing paren"));
-
-    // Bad key.
-    v!("true:you"       => Bool(true), Id("you"));
-    e!("[val true:you]" => s(9, 10, "unexpected colon"));
-
-    // Unexpected colon.
-    v!("z:y:4"       => "z" => Id("y"), Int(4));
-    e!("[val z:y:4]" => s(8, 9, "unexpected colon"));
+fn test_parse_values() {
+    // Basics.
+    t!("{_}"      Block(Id("_")));
+    t!("{name}"   Block(Id("name")));
+    t!("{ke-bab}" Block(Id("ke-bab")));
+    t!("{α}"      Block(Id("α")));
+    t!("{true}"   Block(Bool(true)));
+    t!("{false}"  Block(Bool(false)));
+    t!("{1.0e-4}" Block(Float(1e-4)));
+    t!("{3.15}"   Block(Float(3.15)));
+    t!("{50%}"    Block(Percent(50.0)));
+    t!("{4.5cm}"  Block(Length(4.5, Unit::Cm)));
+    t!("{12e1pt}" Block(Length(12e1, Unit::Pt)));
+
+    // Strings.
+    t!(r#"{"hi"}"#                     Block(Str("hi")));
+    t!(r#"{"a\n[]\"\u{1F680}string"}"# Block(Str("a\n[]\"🚀string")));
+
+    // Colors.
+    t!("{#f7a20500}" Block(Color(RgbaColor::new(0xf7, 0xa2, 0x05, 0))));
+    t!("{#a5}"
+        nodes: [Block(Color(RgbaColor::new(0, 0, 0, 0xff)))],
+        errors: [S(1..4, "invalid color")]);
 }
diff --git a/src/syntax/node.rs b/src/syntax/node.rs
index 102ef3b5..866c935e 100644
--- a/src/syntax/node.rs
+++ b/src/syntax/node.rs
@@ -6,19 +6,20 @@ use super::*;
 /// code.
 #[derive(Debug, Clone, PartialEq)]
 pub enum SynNode {
-    /// Whitespace containing less than two newlines.
-    Space,
     /// Plain text.
     Text(String),
 
+    /// Whitespace containing less than two newlines.
+    Space,
     /// A forced line break.
     Linebreak,
     /// A paragraph break.
     Parbreak,
-    /// Emphasized text was enabled / disabled.
-    Emph,
+
     /// Strong text was enabled / disabled.
     Strong,
+    /// Emphasized text was enabled / disabled.
+    Emph,
 
     /// A section heading.
     Heading(NodeHeading),
diff --git a/src/syntax/token.rs b/src/syntax/token.rs
index 12f4d10d..b365d8d3 100644
--- a/src/syntax/token.rs
+++ b/src/syntax/token.rs
@@ -26,16 +26,16 @@ pub enum Token<'s> {
     Star,
     /// An underscore: `_`.
     Underscore,
-    /// A hashtag indicating a section heading: `#`.
-    Hashtag,
     /// A tilde: `~`.
     Tilde,
     /// A backslash followed by whitespace: `\`.
     Backslash,
-    /// A unicode escape sequence: `\u{1F5FA}`.
-    UnicodeEscape(TokenUnicodeEscape<'s>),
+    /// A hashtag indicating a section heading: `#`.
+    Hashtag,
     /// A raw block: `` `...` ``.
     Raw(TokenRaw<'s>),
+    /// A unicode escape sequence: `\u{1F5FA}`.
+    UnicodeEscape(TokenUnicodeEscape<'s>),
 
     /// A left bracket: `[`.
     LeftBracket,