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markdown: Add support for HTML table column align attribute #41163

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Oct 25, 2025
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markdown: Add support for HTML table column align attribute #41163

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2 changes: 1 addition & 1 deletion crates/markdown_preview/src/markdown_elements.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -106,7 +106,6 @@ pub struct ParsedMarkdownTable {
pub source_range: Range<usize>,
pub header: Vec<ParsedMarkdownTableRow>,
pub body: Vec<ParsedMarkdownTableRow>,
pub column_alignments: Vec<ParsedMarkdownTableAlignment>,
}

#[derive(Debug, Clone, Copy, Default)]
Expand All @@ -126,6 +125,7 @@ pub struct ParsedMarkdownTableColumn {
pub row_span: usize,
pub is_header: bool,
pub children: MarkdownParagraph,
pub alignment: ParsedMarkdownTableAlignment,
}

#[derive(Debug)]
Expand Down
192 changes: 167 additions & 25 deletions crates/markdown_preview/src/markdown_parser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -466,7 +466,10 @@ impl<'a> MarkdownParser<'a> {
let mut body = vec![];
let mut row_columns = vec![];
let mut in_header = true;
let column_alignments = alignment.iter().map(Self::convert_alignment).collect();
let column_alignments = alignment
.iter()
.map(Self::convert_alignment)
.collect::<Vec<_>>();

loop {
if self.eof() {
Expand All @@ -489,6 +492,10 @@ impl<'a> MarkdownParser<'a> {
row_span: 1,
is_header: in_header,
children: cell_contents,
alignment: column_alignments
.get(row_columns.len())
.copied()
.unwrap_or_default(),
});
}
Event::End(TagEnd::TableHead) | Event::End(TagEnd::TableRow) => {
Expand All @@ -515,7 +522,6 @@ impl<'a> MarkdownParser<'a> {
source_range,
header,
body,
column_alignments,
}
}

Expand Down Expand Up @@ -988,6 +994,8 @@ impl<'a> MarkdownParser<'a> {
let mut children = MarkdownParagraph::new();
self.consume_paragraph(source_range, node, &mut children);

let is_header = matches!(name.local, local_name!("th"));

Some(ParsedMarkdownTableColumn {
col_span: std::cmp::max(
Self::attr_value(attrs, local_name!("colspan"))
Expand All @@ -1001,8 +1009,22 @@ impl<'a> MarkdownParser<'a> {
.unwrap_or(1),
1,
),
is_header: matches!(name.local, local_name!("th")),
is_header,
children,
alignment: Self::attr_value(attrs, local_name!("align"))
.and_then(|align| match align.as_str() {
"left" => Some(ParsedMarkdownTableAlignment::Left),
"center" => Some(ParsedMarkdownTableAlignment::Center),
"right" => Some(ParsedMarkdownTableAlignment::Right),
_ => None,
})
.unwrap_or_else(|| {
if is_header {
ParsedMarkdownTableAlignment::Center
} else {
ParsedMarkdownTableAlignment::default()
}
}),
})
}
_ => None,
Expand Down Expand Up @@ -1155,7 +1177,6 @@ impl<'a> MarkdownParser<'a> {
Some(ParsedMarkdownTable {
source_range,
body: body_rows,
column_alignments: Vec::default(),
header: header_rows,
})
} else {
Expand Down Expand Up @@ -1653,17 +1674,53 @@ mod tests {
children: vec![ParsedMarkdownElement::Table(table(
0..366,
vec![row(vec![
column(1, 1, true, text("Id", 0..366)),
column(1, 1, true, text("Name ", 0..366))
column(
1,
1,
true,
text("Id", 0..366),
ParsedMarkdownTableAlignment::Center
),
column(
1,
1,
true,
text("Name ", 0..366),
ParsedMarkdownTableAlignment::Center
)
])],
vec![
row(vec![
column(1, 1, false, text("1", 0..366)),
column(1, 1, false, text("Chris", 0..366))
column(
1,
1,
false,
text("1", 0..366),
ParsedMarkdownTableAlignment::None
),
column(
1,
1,
false,
text("Chris", 0..366),
ParsedMarkdownTableAlignment::None
)
]),
row(vec![
column(1, 1, false, text("2", 0..366)),
column(1, 1, false, text("Dennis", 0..366))
column(
1,
1,
false,
text("2", 0..366),
ParsedMarkdownTableAlignment::None
),
column(
1,
1,
false,
text("Dennis", 0..366),
ParsedMarkdownTableAlignment::None
)
]),
],
))],
Expand Down Expand Up @@ -1697,12 +1754,36 @@ mod tests {
vec![],
vec![
row(vec![
column(1, 1, false, text("1", 0..240)),
column(1, 1, false, text("Chris", 0..240))
column(
1,
1,
false,
text("1", 0..240),
ParsedMarkdownTableAlignment::None
),
column(
1,
1,
false,
text("Chris", 0..240),
ParsedMarkdownTableAlignment::None
)
]),
row(vec![
column(1, 1, false, text("2", 0..240)),
column(1, 1, false, text("Dennis", 0..240))
column(
1,
1,
false,
text("2", 0..240),
ParsedMarkdownTableAlignment::None
),
column(
1,
1,
false,
text("Dennis", 0..240),
ParsedMarkdownTableAlignment::None
)
]),
],
))],
Expand Down Expand Up @@ -1730,8 +1811,20 @@ mod tests {
children: vec![ParsedMarkdownElement::Table(table(
0..150,
vec![row(vec![
column(1, 1, true, text("Id", 0..150)),
column(1, 1, true, text("Name", 0..150))
column(
1,
1,
true,
text("Id", 0..150),
ParsedMarkdownTableAlignment::Center
),
column(
1,
1,
true,
text("Name", 0..150),
ParsedMarkdownTableAlignment::Center
)
])],
vec![],
))],
Expand Down Expand Up @@ -1915,8 +2008,20 @@ Some other content
let expected_table = table(
0..48,
vec![row(vec![
column(1, 1, true, text("Header 1", 1..11)),
column(1, 1, true, text("Header 2", 12..22)),
column(
1,
1,
true,
text("Header 1", 1..11),
ParsedMarkdownTableAlignment::None,
),
column(
1,
1,
true,
text("Header 2", 12..22),
ParsedMarkdownTableAlignment::None,
),
])],
vec![],
);
Expand All @@ -1938,17 +2043,53 @@ Some other content
let expected_table = table(
0..95,
vec![row(vec![
column(1, 1, true, text("Header 1", 1..11)),
column(1, 1, true, text("Header 2", 12..22)),
column(
1,
1,
true,
text("Header 1", 1..11),
ParsedMarkdownTableAlignment::None,
),
column(
1,
1,
true,
text("Header 2", 12..22),
ParsedMarkdownTableAlignment::None,
),
])],
vec![
row(vec![
column(1, 1, false, text("Cell 1", 49..59)),
column(1, 1, false, text("Cell 2", 60..70)),
column(
1,
1,
false,
text("Cell 1", 49..59),
ParsedMarkdownTableAlignment::None,
),
column(
1,
1,
false,
text("Cell 2", 60..70),
ParsedMarkdownTableAlignment::None,
),
]),
row(vec![
column(1, 1, false, text("Cell 3", 73..83)),
column(1, 1, false, text("Cell 4", 84..94)),
column(
1,
1,
false,
text("Cell 3", 73..83),
ParsedMarkdownTableAlignment::None,
),
column(
1,
1,
false,
text("Cell 4", 84..94),
ParsedMarkdownTableAlignment::None,
),
]),
],
);
Expand Down Expand Up @@ -2410,7 +2551,6 @@ fn main() {
body: Vec<ParsedMarkdownTableRow>,
) -> ParsedMarkdownTable {
ParsedMarkdownTable {
column_alignments: Vec::new(),
source_range,
header,
body,
Expand All @@ -2426,12 +2566,14 @@ fn main() {
row_span: usize,
is_header: bool,
children: MarkdownParagraph,
alignment: ParsedMarkdownTableAlignment,
) -> ParsedMarkdownTableColumn {
ParsedMarkdownTableColumn {
col_span,
row_span,
is_header,
children,
alignment,
}
}

Expand Down
18 changes: 4 additions & 14 deletions crates/markdown_preview/src/markdown_renderer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -497,7 +497,7 @@ fn render_markdown_table(parsed: &ParsedMarkdownTable, cx: &mut RenderContext) -
for (row_idx, row) in parsed.header.iter().chain(parsed.body.iter()).enumerate() {
let mut col_idx = 0;

for (cell_idx, cell) in row.columns.iter().enumerate() {
for cell in row.columns.iter() {
// Skip columns occupied by row-spanning cells from previous rows
while col_idx < max_column_count && grid_occupied[row_idx][col_idx] {
col_idx += 1;
Expand All @@ -507,19 +507,7 @@ fn render_markdown_table(parsed: &ParsedMarkdownTable, cx: &mut RenderContext) -
break;
}

let alignment = parsed
.column_alignments
.get(cell_idx)
.copied()
.unwrap_or_else(|| {
if cell.is_header {
ParsedMarkdownTableAlignment::Center
} else {
ParsedMarkdownTableAlignment::None
}
});

let container = match alignment {
let container = match cell.alignment {
ParsedMarkdownTableAlignment::Left | ParsedMarkdownTableAlignment::None => div(),
ParsedMarkdownTableAlignment::Center => v_flex().items_center(),
ParsedMarkdownTableAlignment::Right => v_flex().items_end(),
Expand Down Expand Up @@ -900,6 +888,7 @@ mod tests {
row_span,
is_header: false,
children,
alignment: ParsedMarkdownTableAlignment::None,
}
}

Expand All @@ -913,6 +902,7 @@ mod tests {
row_span,
is_header: false,
children,
alignment: ParsedMarkdownTableAlignment::None,
}
}

Expand Down
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