add: toc support

src/markdown.rs

@@ -3,9 +3,9 @@ use std::collections::HashSet;
 pub fn render_markdown(input: &str) -> String {
     let html = tetratto_shared::markdown::render_markdown_dirty(&parse_page(&parse_details(
         &parse_text_color(&parse_highlight(&parse_link(&parse_image(
-            &parse_image_size(&parse_underline(&parse_comment(
+            &parse_image_size(&parse_toc(&parse_underline(&parse_comment(
                 &input.replace("[/]", "<br />"),
-            ))),
+            )))),
         )))),
     )))
     .replace("$per", "%");
@@ -811,7 +811,7 @@ pub fn parse_page(input: &str) -> String {
 /// Parse the markdown syntax for the expandable `<details>` element.
 ///
 /// Similar to the [`parse_page`] page definitions, details elements are denoted
-/// with two ampersand symbols. The opening line should look like `&& [summary]; [open?]`.
+/// with two ampersand symbols. The opening line should look like `&& [summary]`.
 ///
 /// The block is closed with a line of exactly two ampersand symbols.
 ///
@@ -883,3 +883,88 @@ pub fn parse_details(input: &str) -> String {
 
     output
 }
+
+/// Get the list of headers needed for [`parse_toc`].
+pub fn get_toc_list(input: &str) -> (String, String) {
+    let mut output = String::new();
+    let mut toc = String::new();
+    let mut in_pre = false;
+
+    for line in input.split("\n") {
+        if line.starts_with("```") {
+            in_pre = !in_pre;
+            output.push_str(&format!("{line}\n"));
+            continue;
+        }
+
+        if in_pre {
+            output.push_str(&format!("{line}\n"));
+            continue;
+        }
+
+        // not in pre
+        if line.starts_with("#") {
+            // get heading count
+            let mut hc = 0;
+
+            for x in line.chars() {
+                if x != '#' {
+                    break;
+                }
+
+                hc += 1;
+            }
+
+            // add heading with id
+            let x = line.replacen(&"#".repeat(hc), "", 1);
+            let htext = x.trim();
+
+            let id = htext.to_lowercase().replace(" ", "_");
+            output.push_str(&format!("<h{hc} id=\"{id}\">{htext}</h{hc}>\n"));
+
+            // add heading to toc
+            toc += &format!("{}- [{htext}](#{id})\n", "  ".repeat(hc));
+
+            // ...
+            continue;
+        }
+
+        // otherwise
+        output.push_str(&format!("{line}\n"));
+    }
+
+    (toc, output)
+}
+
+/// Parse the `[toc]` table-of-contents syntax.
+pub fn parse_toc(input: &str) -> String {
+    let (toc_list, new_input) = get_toc_list(input);
+
+    let mut output = String::new();
+    let mut in_pre = false;
+
+    for line in new_input.split("\n") {
+        if line.starts_with("```") {
+            in_pre = !in_pre;
+            output.push_str(&format!("{line}\n"));
+            continue;
+        }
+
+        if in_pre {
+            output.push_str(&format!("{line}\n"));
+            continue;
+        }
+
+        // not in pre
+        if line.len() == 5 && line.to_lowercase() == "[toc]" {
+            // add toc
+            output.push_str(&toc_list);
+            continue;
+        }
+
+        // otherwise
+        output.push_str(&format!("{line}\n"));
+    }
+
+    output
+}