From b2b2593832cc17282f3e41fa54dcb2923cbf7354 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michael=20F=C3=A4rber?= <01mf02@gmail.com>
Date: Tue, 21 Jan 2025 11:07:52 +0100
Subject: [PATCH] Print cells in table header as `<th>` as opposed to `<td>`.

---
 crates/typst-library/src/model/table.rs | 90 ++++++++++++++-----------
 1 file changed, 52 insertions(+), 38 deletions(-)

diff --git a/crates/typst-library/src/model/table.rs b/crates/typst-library/src/model/table.rs
index bdcdf68e7..ba7924422 100644
--- a/crates/typst-library/src/model/table.rs
+++ b/crates/typst-library/src/model/table.rs
@@ -9,9 +9,9 @@ use crate::foundations::{
     cast, elem, scope, Content, NativeElement, Packed, Show, Smart, StyleChain,
     TargetElem,
 };
-use crate::html::{tag, HtmlAttr, HtmlAttrs, HtmlElem};
+use crate::html::{tag, HtmlAttr, HtmlAttrs, HtmlElem, HtmlTag};
 use crate::introspection::Locator;
-use crate::layout::grid::resolve::table_to_cellgrid;
+use crate::layout::grid::resolve::{table_to_cellgrid, Cell, CellGrid, Entry};
 use crate::layout::{
     show_grid_cell, Abs, Alignment, BlockElem, Celled, GridCell, GridFooter, GridHLine,
     GridHeader, GridVLine, Length, OuterHAlignment, OuterVAlignment, Rel, Sides,
@@ -262,34 +262,61 @@ impl TableElem {
     type TableFooter;
 }
 
+fn show_cell_html(tag: HtmlTag, cell: &Cell, styles: StyleChain) -> Content {
+    let cell = cell.body.clone();
+    let Some(cell) = cell.to_packed::<TableCell>() else { return cell };
+    let mut attrs = HtmlAttrs::default();
+    let span = |n: NonZeroUsize| (n != NonZeroUsize::MIN).then(|| n.to_string());
+    if let Some(colspan) = span(cell.colspan(styles)) {
+        attrs.push(HtmlAttr::constant("colspan"), colspan);
+    }
+    if let Some(rowspan) = span(cell.rowspan(styles)) {
+        attrs.push(HtmlAttr::constant("rowspan"), rowspan);
+    }
+    HtmlElem::new(tag)
+        .with_body(Some(cell.body.clone()))
+        .with_attrs(attrs)
+        .pack()
+        .spanned(cell.span())
+}
+
+fn show_cellgrid_html(grid: CellGrid, styles: StyleChain) -> Content {
+    let elem = |tag, body| HtmlElem::new(tag).with_body(Some(body)).pack();
+    let mut rows: Vec<_> = grid.entries.chunks(grid.cols.len()).collect();
+
+    let tr = |tag, row: &[Entry]| {
+        let row = row
+            .iter()
+            .flat_map(|entry| entry.as_cell())
+            .map(|cell| show_cell_html(tag, cell, styles));
+        elem(tag::tr, Content::sequence(row))
+    };
+
+    let footer = grid.footer.map(|ft| {
+        let rows = rows.drain(ft.unwrap().start..);
+        elem(tag::tfoot, Content::sequence(rows.map(|row| tr(tag::td, row))))
+    });
+    let header = grid.header.map(|hd| {
+        let rows = rows.drain(..hd.unwrap().end);
+        elem(tag::thead, Content::sequence(rows.map(|row| tr(tag::th, row))))
+    });
+
+    let mut body = Content::sequence(rows.into_iter().map(|row| tr(tag::td, row)));
+    if header.is_some() || footer.is_some() {
+        body = elem(tag::tbody, body);
+    }
+
+    let content = header.into_iter().chain(core::iter::once(body)).chain(footer);
+    elem(tag::table, Content::sequence(content))
+}
+
 impl Show for Packed<TableElem> {
     fn show(&self, engine: &mut Engine, styles: StyleChain) -> SourceResult<Content> {
         Ok(if TargetElem::target_in(styles).is_html() {
             // TODO: This is a hack, it is not clear whether the locator is actually used by HTML.
             // How can we find out whether locator is actually used?
             let locator = Locator::root();
-            let elem = |tag, body| HtmlElem::new(tag).with_body(Some(body)).pack();
-            let grid = table_to_cellgrid(self, engine, locator, styles)?;
-            let rows = grid.entries.chunks(grid.cols.len()).map(|row| {
-                let row = row.iter().flat_map(|entry| entry.as_cell());
-                elem(tag::tr, Content::sequence(row.map(|cell| cell.body.clone())))
-            });
-            let mut rows: Vec<_> = rows.collect();
-
-            let footer = grid.footer.map(|ft| {
-                elem(tag::tfoot, Content::sequence(rows.drain(ft.unwrap().start..)))
-            });
-            let header = grid.header.map(|hd| {
-                elem(tag::thead, Content::sequence(rows.drain(..hd.unwrap().end)))
-            });
-
-            let mut body = Content::sequence(rows);
-            if header.is_some() || footer.is_some() {
-                body = elem(tag::tbody, body);
-            }
-
-            let content = header.into_iter().chain(core::iter::once(body)).chain(footer);
-            elem(tag::table, Content::sequence(content))
+            show_cellgrid_html(table_to_cellgrid(self, engine, locator, styles)?, styles)
         } else {
             BlockElem::multi_layouter(self.clone(), engine.routines.layout_table).pack()
         }
@@ -737,20 +764,7 @@ cast! {
 
 impl Show for Packed<TableCell> {
     fn show(&self, _engine: &mut Engine, styles: StyleChain) -> SourceResult<Content> {
-        if TargetElem::target_in(styles).is_html() {
-            let mut attrs = HtmlAttrs::default();
-            let span = |n: NonZeroUsize| (n != NonZeroUsize::MIN).then(|| n.to_string());
-            if let Some(colspan) = span(self.colspan(styles)) {
-                attrs.push(HtmlAttr::constant("colspan"), colspan);
-            }
-            if let Some(rowspan) = span(self.rowspan(styles)) {
-                attrs.push(HtmlAttr::constant("rowspan"), rowspan);
-            }
-            let body = Some(self.body.clone());
-            Ok(HtmlElem::new(tag::td).with_body(body).with_attrs(attrs).pack())
-        } else {
-            show_grid_cell(self.body.clone(), self.inset(styles), self.align(styles))
-        }
+        show_grid_cell(self.body.clone(), self.inset(styles), self.align(styles))
     }
 }