Compare heading tags.

src/compare/diff.rs

@@ -1,3 +1,5 @@
+use std::collections::HashSet;
+
 use super::util::assert_bounds;
 use super::util::assert_name;
 use crate::parser::sexp::Token;
@@ -58,6 +60,7 @@ use crate::parser::Timestamp;
 use crate::parser::Underline;
 use crate::parser::Verbatim;
 use crate::parser::VerseBlock;
+use crate::parser::sexp::unquote;
 
 #[derive(Debug)]
 pub struct DiffResult {
@@ -323,6 +326,7 @@ fn compare_heading<'s>(
     let children = emacs.as_list()?;
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
+    let mut message = None;
     let emacs_name = "headline";
     if assert_name(emacs, emacs_name).is_err() {
         this_status = DiffStatus::Bad;
@@ -347,8 +351,19 @@ fn compare_heading<'s>(
     for (emacs_child, rust_child) in title.as_list()?.iter().zip(rust.title.iter()) {
         child_status.push(compare_object(source, emacs_child, rust_child)?);
     }
+    let emacs_tags = get_tags_from_heading(emacs)?;
+    let emacs_tags: HashSet<_> = emacs_tags.iter().map(|val| val.as_str()).collect();
+    let rust_tags: HashSet<&str> = rust.tags.iter().map(|val| *val).collect();
+    let difference: Vec<&str> = emacs_tags
+        .symmetric_difference(&rust_tags)
+        .map(|val| *val)
+        .collect();
+    if !difference.is_empty() {
+        this_status = DiffStatus::Bad;
+        message = Some(format!("Mismatched tags: {}", difference.join(", ")));
+    }
 
-    // TODO: Compare tags, todo-keyword, level, priority
+    // TODO: Compare todo-keyword, level, priority
 
     for (emacs_child, rust_child) in children.iter().skip(2).zip(rust.children.iter()) {
         match rust_child {
@@ -364,11 +379,38 @@ fn compare_heading<'s>(
     Ok(DiffResult {
         status: this_status,
         name: emacs_name.to_owned(),
-        message: None,
+        message,
         children: child_status,
     })
 }
 
+fn get_tags_from_heading<'s>(
+    emacs: &'s Token<'s>,
+) -> Result<HashSet<String>, Box<dyn std::error::Error>> {
+    let children = emacs.as_list()?;
+    let attributes_child = children
+        .iter()
+        .nth(1)
+        .ok_or("Should have an attributes child.")?;
+    let attributes_map = attributes_child.as_map()?;
+    let tags = attributes_map
+        .get(":tags")
+        .ok_or("Missing :tags attribute.")?;
+    match tags.as_atom() {
+        Ok("nil") => {
+            return Ok(HashSet::new());
+        }
+        Ok(val) => panic!("Unexpected value for tags: {:?}", val),
+        Err(_) => {}
+    };
+    let tags = {
+        let tags = tags.as_list()?;
+        let strings = tags.iter().map(Token::as_atom).collect::<Result<Vec<&str>, _>>()?;
+        strings.into_iter().map(unquote).collect::<Result<HashSet<String>, _>>()?
+    };
+    Ok(tags)
+}
+
 fn compare_paragraph<'s>(
     source: &'s str,
     emacs: &'s Token<'s>,
@@ -1027,7 +1069,7 @@ fn compare_plain_text<'s>(
             rust.source.len()
         ));
     }
-    let unquoted_text = text.unquote()?;
+    let unquoted_text = unquote(text.text)?;
     if unquoted_text != rust.source {
         this_status = DiffStatus::Bad;
         message = Some(format!(