From 2a86e4db0bb3894d1cc3b94e1a1af31a6cd87b80 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Tue, 14 Mar 2023 22:33:22 +0100
Subject: Reference supplements

---
 src/syntax/ast.rs    | 17 +++++++++++++----
 src/syntax/kind.rs   |  7 +++++--
 src/syntax/lexer.rs  | 12 ++++++------
 src/syntax/parser.rs | 13 +++++++++++--
 4 files changed, 35 insertions(+), 14 deletions(-)

(limited to 'src/syntax')

diff --git a/src/syntax/ast.rs b/src/syntax/ast.rs
index 2fdedbcf..8e48358d 100644
--- a/src/syntax/ast.rs
+++ b/src/syntax/ast.rs
@@ -101,7 +101,7 @@ pub enum Expr {
     Link(Link),
     /// A label: `<intro>`.
     Label(Label),
-    /// A reference: `@target`.
+    /// A reference: `@target`, `@target[..]`.
     Ref(Ref),
     /// A section heading: `= Introduction`.
     Heading(Heading),
@@ -604,14 +604,23 @@ impl Label {
 }
 
 node! {
-    /// A reference: `@target`.
+    /// A reference: `@target`, `@target[..]`.
     Ref
 }
 
 impl Ref {
     /// Get the target.
-    pub fn get(&self) -> &str {
-        self.0.text().trim_start_matches('@')
+    pub fn target(&self) -> &str {
+        self.0
+            .children()
+            .find(|node| node.kind() == SyntaxKind::RefMarker)
+            .map(|node| node.text().trim_start_matches('@'))
+            .unwrap_or_default()
+    }
+
+    /// Get the supplement.
+    pub fn supplement(&self) -> Option<ContentBlock> {
+        self.0.cast_last_match()
     }
 }
 
diff --git a/src/syntax/kind.rs b/src/syntax/kind.rs
index 47b5da31..ce3ae744 100644
--- a/src/syntax/kind.rs
+++ b/src/syntax/kind.rs
@@ -36,8 +36,10 @@ pub enum SyntaxKind {
     Link,
     /// A label: `<intro>`.
     Label,
-    /// A reference: `@target`.
+    /// A reference: `@target`, `@target[..]`.
     Ref,
+    /// Introduces a reference: `@target`.
+    RefMarker,
     /// A section heading: `= Introduction`.
     Heading,
     /// Introduces a section heading: `=`, `==`, ...
@@ -324,12 +326,14 @@ impl SyntaxKind {
             Self::Parbreak => "paragraph break",
             Self::Escape => "escape sequence",
             Self::Shorthand => "shorthand",
+            Self::SmartQuote => "smart quote",
             Self::Strong => "strong content",
             Self::Emph => "emphasized content",
             Self::Raw => "raw block",
             Self::Link => "link",
             Self::Label => "label",
             Self::Ref => "reference",
+            Self::RefMarker => "reference marker",
             Self::Heading => "heading",
             Self::HeadingMarker => "heading marker",
             Self::ListItem => "list item",
@@ -358,7 +362,6 @@ impl SyntaxKind {
             Self::Star => "star",
             Self::Underscore => "underscore",
             Self::Dollar => "dollar sign",
-            Self::SmartQuote => "smart quote",
             Self::Plus => "plus",
             Self::Minus => "minus",
             Self::Slash => "slash",
diff --git a/src/syntax/lexer.rs b/src/syntax/lexer.rs
index 919cce69..8e27d98d 100644
--- a/src/syntax/lexer.rs
+++ b/src/syntax/lexer.rs
@@ -172,7 +172,7 @@ impl Lexer<'_> {
             'h' if self.s.eat_if("ttps://") => self.link(),
             '0'..='9' => self.numbering(start),
             '<' if self.s.at(is_id_continue) => self.label(),
-            '@' if self.s.at(is_id_continue) => self.reference(),
+            '@' => self.ref_marker(),
 
             '.' if self.s.eat_if("..") => SyntaxKind::Shorthand,
             '-' if self.s.eat_if("--") => SyntaxKind::Shorthand,
@@ -297,6 +297,11 @@ impl Lexer<'_> {
         self.text()
     }
 
+    fn ref_marker(&mut self) -> SyntaxKind {
+        self.s.eat_while(is_id_continue);
+        SyntaxKind::RefMarker
+    }
+
     fn label(&mut self) -> SyntaxKind {
         let label = self.s.eat_while(is_id_continue);
         if label.is_empty() {
@@ -310,11 +315,6 @@ impl Lexer<'_> {
         SyntaxKind::Label
     }
 
-    fn reference(&mut self) -> SyntaxKind {
-        self.s.eat_while(is_id_continue);
-        SyntaxKind::Ref
-    }
-
     fn text(&mut self) -> SyntaxKind {
         macro_rules! table {
             ($(|$c:literal)*) => {
diff --git a/src/syntax/parser.rs b/src/syntax/parser.rs
index 201d78fa..127a89d5 100644
--- a/src/syntax/parser.rs
+++ b/src/syntax/parser.rs
@@ -104,8 +104,7 @@ fn markup_expr(p: &mut Parser, at_start: &mut bool) {
         | SyntaxKind::SmartQuote
         | SyntaxKind::Raw
         | SyntaxKind::Link
-        | SyntaxKind::Label
-        | SyntaxKind::Ref => p.eat(),
+        | SyntaxKind::Label => p.eat(),
 
         SyntaxKind::Hashtag => embedded_code_expr(p),
         SyntaxKind::Star => strong(p),
@@ -114,6 +113,7 @@ fn markup_expr(p: &mut Parser, at_start: &mut bool) {
         SyntaxKind::ListMarker if *at_start => list_item(p),
         SyntaxKind::EnumMarker if *at_start => enum_item(p),
         SyntaxKind::TermMarker if *at_start => term_item(p),
+        SyntaxKind::RefMarker => reference(p),
         SyntaxKind::Dollar => formula(p),
 
         SyntaxKind::LeftBracket
@@ -198,6 +198,15 @@ fn term_item(p: &mut Parser) {
     p.wrap(m, SyntaxKind::TermItem);
 }
 
+fn reference(p: &mut Parser) {
+    let m = p.marker();
+    p.assert(SyntaxKind::RefMarker);
+    if p.directly_at(SyntaxKind::LeftBracket) {
+        content_block(p);
+    }
+    p.wrap(m, SyntaxKind::Ref);
+}
+
 fn whitespace_line(p: &mut Parser) {
     while !p.newline() && p.current().is_trivia() {
         p.eat();
-- 
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