Primes should not further raise next superscript's position (#4492)

Co-authored-by: Ian Wrzesinski <133046678+wrzian@users.noreply.github.com>

crates/typst-syntax/src/parser.rs

@@ -393,11 +393,6 @@ fn math_expr_prec(p: &mut Parser, min_prec: usize, stop: SyntaxKind) {
             continue;
         }
 
-        // Separate primes and superscripts to different attachments.
-        if primed && p.current() == SyntaxKind::Hat {
-            p.wrap(m, SyntaxKind::MathAttach);
-        }
-
         let Some((kind, stop, assoc, mut prec)) = math_op(p.current()) else {
             // No attachments, so we need to wrap primes as attachment.
             if primed {
@@ -429,7 +424,7 @@ fn math_expr_prec(p: &mut Parser, min_prec: usize, stop: SyntaxKind) {
         math_expr_prec(p, prec, stop);
         math_unparen(p, m2);
 
-        if p.eat_if(SyntaxKind::Underscore) || (!primed && p.eat_if(SyntaxKind::Hat)) {
+        if p.eat_if(SyntaxKind::Underscore) || p.eat_if(SyntaxKind::Hat) {
             let m3 = p.marker();
             math_expr_prec(p, prec, SyntaxKind::End);
             math_unparen(p, m3);

crates/typst/src/eval/math.rs

@@ -54,7 +54,11 @@ impl Eval for ast::MathAttach<'_> {
 
         if let Some(expr) = self.top() {
             elem.push_t(Some(expr.eval_display(vm)?));
-        } else if let Some(primes) = self.primes() {
+        }
+
+        // Always attach primes in scripts style (not limits style),
+        // i.e. at the top-right corner.
+        if let Some(primes) = self.primes() {
             elem.push_tr(Some(primes.eval(vm)?));
         }
 

crates/typst/src/math/attach.rs

@@ -52,31 +52,47 @@ pub struct AttachElem {
 impl LayoutMath for Packed<AttachElem> {
     #[typst_macros::time(name = "math.attach", span = self.span())]
     fn layout_math(&self, ctx: &mut MathContext, styles: StyleChain) -> SourceResult<()> {
-        type GetAttachment = fn(&AttachElem, styles: StyleChain) -> Option<Content>;
-
-        let layout_attachment =
-            |ctx: &mut MathContext, styles: StyleChain, getter: GetAttachment| {
-                getter(self, styles)
-                    .map(|elem| ctx.layout_into_fragment(&elem, styles))
-                    .transpose()
-            };
-
         let base = ctx.layout_into_fragment(self.base(), styles)?;
 
         let sup_style = style_for_superscript(styles);
-        let tl = layout_attachment(ctx, styles.chain(&sup_style), AttachElem::tl)?;
+        let sup_style_chain = styles.chain(&sup_style);
-        let tr = layout_attachment(ctx, styles.chain(&sup_style), AttachElem::tr)?;
+        let tl = self.tl(sup_style_chain);
-        let t = layout_attachment(ctx, styles.chain(&sup_style), AttachElem::t)?;
+        let tr = self.tr(sup_style_chain);
+        let primed = tr.as_ref().is_some_and(|content| content.is::<PrimesElem>());
+        let t = self.t(sup_style_chain);
 
         let sub_style = style_for_subscript(styles);
-        let bl = layout_attachment(ctx, styles.chain(&sub_style), AttachElem::bl)?;
+        let sub_style_chain = styles.chain(&sub_style);
-        let br = layout_attachment(ctx, styles.chain(&sub_style), AttachElem::br)?;
+        let bl = self.bl(sub_style_chain);
-        let b = layout_attachment(ctx, styles.chain(&sub_style), AttachElem::b)?;
+        let br = self.br(sub_style_chain);
+        let b = self.b(sub_style_chain);
 
         let limits = base.limits().active(styles);
-        let (t, tr) = if limits || tr.is_some() { (t, tr) } else { (None, t) };
+        let (t, tr) = match (t, tr) {
+            (Some(t), Some(tr)) if primed && !limits => (None, Some(tr + t)),
+            (Some(t), None) if !limits => (None, Some(t)),
+            (t, tr) => (t, tr),
+        };
         let (b, br) = if limits || br.is_some() { (b, br) } else { (None, b) };
-        layout_attachments(ctx, styles, base, [tl, t, tr, bl, b, br])
+
+        macro_rules! layout {
+            ($content:ident, $style_chain:ident) => {
+                $content
+                    .map(|elem| ctx.layout_into_fragment(&elem, $style_chain))
+                    .transpose()
+            };
+        }
+
+        let fragments = [
+            layout!(tl, sup_style_chain)?,
+            layout!(t, sup_style_chain)?,
+            layout!(tr, sup_style_chain)?,
+            layout!(bl, sub_style_chain)?,
+            layout!(b, sub_style_chain)?,
+            layout!(br, sub_style_chain)?,
+        ];
+
+        layout_attachments(ctx, styles, base, fragments)
     }
 }
 

tests/suite/math/primes.typ

@@ -12,7 +12,11 @@ $a'_b^c$, $a_b'^c$, $a_b^c'$, $a_b'^c'^d'$
 
 $(a'_b')^(c'_d')$, $a'/b'$, $a_b'/c_d'$
 
-$∫'$, $∑'$, $ ∑'_S' $
+$∫'$, $∑'$, $a'^2^2$, $a'_2_2$
+
+$f_n'^a'$, $f^a'_n'$
+
+$ ∑'_S' $
 
 --- math-primes-attach ---
 // Test attaching primes only
@@ -48,3 +52,12 @@ $
   #g''''''''''''''''' \
   gg'
 $
+
+--- math-primes-with-superscript ---
+// Test prime symbols don't raise the superscript position
+$
+  sqrt(f)/f
+  sqrt(f^2)/f^2
+  sqrt(f'^2)/f'^2
+  sqrt(f''_n^2)/f''^2_n
+$