Add parser for node text with support for headers

src/syntax/content.rs

@@ -0,0 +1,57 @@
+use std::fmt::Write as _;
+use crate::dev::log;
+
+pub fn parse(text: &str) -> String {
+    let mut out_text: Vec<String> = Vec::new();
+
+    for line in text.lines() {
+        if line.is_empty() || line.replace(" ", "").is_empty() {
+            continue;
+        }
+
+        let mut out_line: String = line.to_owned();
+        let words: Vec<String> = line.split(" ").map(str::to_string).collect();
+        let first_word: &String =
+            words.first().unwrap_or_else(|| unreachable!());
+
+        if is_header(first_word) {
+            out_line = parse_header(&out_line, first_word);
+        }
+        // if not special, default to treating line as a paragraph
+        else {
+            out_line.insert_str(0, "<p>");
+            out_line.push_str("</p>");
+        }
+
+        out_text.push(out_line);
+    }
+
+    out_text.join("\n")
+}
+
+fn is_header(lexeme: &str) -> bool {
+    !lexeme.trim().is_empty()
+        && lexeme.replace("#", "").is_empty()
+        && lexeme.len() <= 6
+}
+
+fn parse_header(line: &str, first_word: &str) -> String {
+    log(&parse_header, &format!("Parsing: {line:?}"));
+
+    let header_level = first_word.len();
+    log(&parse, &format!("Header level is {header_level}"));
+    let header_text = line.to_owned().replace(first_word, "");
+    let mut w = String::with_capacity(header_text.len().strict_add(9));
+    let alloc = w.capacity();
+    match write!(w, "<h{header_level}>{header_text}</h{header_level}>") {
+        Ok(()) => (),
+        Err(e) => panic!("{e:?}"),
+    }
+    if alloc != w.capacity() {
+        log(
+            &parse_header,
+            &format!("w reallocated to {} despite prediction", w.capacity()),
+        );
+    }
+    w
+}