Add figure separator field (#1791)

crates/typst-library/src/meta/figure.rs

@@ -359,12 +359,11 @@ impl Outlinable for FigureElem {
             return Ok(None);
         }
 
-        let Some(mut caption) =
+        let Some(caption) = self.caption(StyleChain::default()) else {
-            self.caption(StyleChain::default()).map(|caption| caption.body())
-        else {
             return Ok(None);
         };
 
+        let mut realized = caption.body();
         if let (
             Smart::Custom(Some(Supplement::Content(mut supplement))),
             Some(counter),
@@ -381,10 +380,12 @@ impl Outlinable for FigureElem {
                 supplement += TextElem::packed('\u{a0}');
             }
 
-            caption = supplement + numbers + TextElem::packed(": ") + caption;
+            let separator = caption.separator(StyleChain::default());
+
+            realized = supplement + numbers + separator + caption.body();
         }
 
-        Ok(Some(caption))
+        Ok(Some(realized))
     }
 }
 
@@ -444,6 +445,19 @@ pub struct FigureCaption {
     })]
     pub position: VAlign,
 
+    /// The separator which will appear between the number and body.
+    ///
+    /// ```example
+    /// #set figure.caption(separator: [ --- ])
+    ///
+    /// #figure(
+    ///   rect[Hello],
+    ///   caption: [A rectangle],
+    /// )
+    /// ```
+    #[default(TextElem::packed(": "))]
+    pub separator: Content,
+
     /// The caption's body.
     ///
     /// Can be used alongside `kind`, `supplement`, `counter`, `numbering`, and
@@ -487,13 +501,14 @@ pub struct FigureCaption {
 impl Synthesize for FigureCaption {
     fn synthesize(&mut self, _: &mut Vt, styles: StyleChain) -> SourceResult<()> {
         self.push_position(self.position(styles));
+        self.push_separator(self.separator(styles));
         Ok(())
     }
 }
 
 impl Show for FigureCaption {
     #[tracing::instrument(name = "FigureCaption::show", skip_all)]
-    fn show(&self, vt: &mut Vt, _: StyleChain) -> SourceResult<Content> {
+    fn show(&self, vt: &mut Vt, styles: StyleChain) -> SourceResult<Content> {
         let mut realized = self.body();
 
         if let (Some(mut supplement), Some(numbering), Some(counter), Some(location)) =
@@ -503,7 +518,7 @@ impl Show for FigureCaption {
             if !supplement.is_empty() {
                 supplement += TextElem::packed('\u{a0}');
             }
-            realized = supplement + numbers + TextElem::packed(": ") + realized;
+            realized = supplement + numbers + self.separator(styles) + realized;
         }
 
         Ok(realized)

tests/typ/meta/figure.typ

@@ -100,3 +100,12 @@ We can clearly see that @fig-cylinder and
 #show figure: set block(breakable: true)
 
 #figure(table[a][b][c][d][e], caption: [A table])
+
+---
+// Test custom separator for figure caption
+#set figure.caption(separator: [ --- ])
+
+#figure(
+  table(columns: 2)[a][b],
+  caption: [The table with custom separator.],
+)