1 files changed, 20 insertions, 0 deletions
diff --git a/converter/src/syntax_checker.rs b/converter/src/syntax_checker.rs
index 334fa9d..52021c7 100644
--- a/converter/src/syntax_checker.rs
+++ b/converter/src/syntax_checker.rs
@@ -1,3 +1,5 @@
+use regex::Regex;
+
 use crate::error::Exit;
 
 pub fn check_markdown_syntax(i: &String) -> Result<(), Exit> {
@@ -199,3 +201,21 @@ pub fn check_markdown_syntax(i: &String) -> Result<(), Exit> {
 
     Ok(())
 }
+
+/// Check for duplicate markers
+pub fn check_duplicate_marker(input: &String) -> Result<(), Exit> {
+    let mut seen = std::collections::HashSet::new();
+    let heading_re = Regex::new(r"^(#{1,5})\s+(.+)$").unwrap();
+
+    for line in input.lines() {
+        if let Some(caps) = heading_re.captures(line) {
+            let heading_text = caps[2].trim().to_string();
+            if seen.contains(&heading_text) {
+                return Err(Exit::DuplicateMarker(heading_text));
+            }
+            seen.insert(heading_text);
+        }
+    }
+
+    Ok(())
+}