C14.14: export HTML, HTML and folder, PDF (MuPDF story in the PDF worker) and plain text; print; rich copy

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/ely-mark/src/output/plain.rs

@@ -0,0 +1,62 @@
+//! Markdown as plain text: words, code and TeX, no marks.
+
+use std::io;
+
+use ely_gpui_component::documents::markdown_options;
+use markdown::mdast::Node;
+
+/// `text` as plain text, a blank line between blocks.
+pub fn plain(text: &str) -> io::Result<String> {
+    let tree = markdown::to_mdast(text, &markdown_options())
+        .map_err(|error| io::Error::other(error.to_string()))?;
+    let mut blocks = Vec::new();
+    for child in tree.children().into_iter().flatten() {
+        block(child, &mut blocks);
+    }
+    Ok(blocks.join("\n\n") + "\n")
+}
+
+fn block(node: &Node, blocks: &mut Vec<String>) {
+    match node {
+        Node::Code(code) => blocks.push(code.value.clone()),
+        Node::Math(math) => blocks.push(math.value.clone()),
+        Node::List(list) => {
+            let items = list.children.iter().map(|item| {
+                let mut inner = Vec::new();
+                for child in item.children().into_iter().flatten() {
+                    block(child, &mut inner);
+                }
+                inner.join("\n")
+            });
+            blocks.push(items.collect::<Vec<_>>().join("\n"));
+        }
+        Node::Table(table) => {
+            let rows = table.children.iter().map(|row| {
+                let cells = row.children().into_iter().flatten().map(words);
+                cells.collect::<Vec<_>>().join("\t")
+            });
+            blocks.push(rows.collect::<Vec<_>>().join("\n"));
+        }
+        Node::Blockquote(_) | Node::FootnoteDefinition(_) => {
+            for child in node.children().into_iter().flatten() {
+                block(child, blocks);
+            }
+        }
+        Node::Paragraph(_) | Node::Heading(_) => blocks.push(words(node)),
+        // Front matter, HTML, rules and definitions are not words.
+        _ => {}
+    }
+}
+
+/// The words of an inline run.
+fn words(node: &Node) -> String {
+    match node {
+        Node::Text(text) => text.value.clone(),
+        Node::InlineCode(code) => code.value.clone(),
+        Node::InlineMath(math) => math.value.clone(),
+        Node::Break(_) => "\n".into(),
+        Node::Image(image) => image.alt.clone(),
+        Node::Html(_) => String::new(),
+        _ => node.children().into_iter().flatten().map(words).collect(),
+    }
+}