Add support for babel-call keywords.

src/compare/diff.rs

@@ -306,6 +306,7 @@ fn compare_element<'s>(
         Element::FixedWidthArea(obj) => compare_fixed_width_area(source, emacs, obj),
         Element::HorizontalRule(obj) => compare_horizontal_rule(source, emacs, obj),
         Element::Keyword(obj) => compare_keyword(source, emacs, obj),
+        Element::BabelCall(obj) => compare_babel_call(source, emacs, obj),
         Element::LatexEnvironment(obj) => compare_latex_environment(source, emacs, obj),
     };
     match compare_result {
@@ -1447,6 +1448,52 @@ fn compare_keyword<'s>(
     .into())
 }
 
+fn compare_babel_call<'s>(
+    source: &'s str,
+    emacs: &'s Token<'s>,
+    rust: &'s Keyword<'s>,
+) -> Result<DiffEntry<'s>, Box<dyn std::error::Error>> {
+    let child_status = Vec::new();
+    let mut this_status = DiffStatus::Good;
+    let mut message = None;
+    let emacs_name = "babel-call";
+    if assert_name(emacs, emacs_name).is_err() {
+        this_status = DiffStatus::Bad;
+    }
+
+    match assert_bounds(source, emacs, rust) {
+        Err(err) => {
+            this_status = DiffStatus::Bad;
+            message = Some(err.to_string())
+        }
+        Ok(_) => {}
+    };
+
+    // TODO: compare :call :inside-header :arguments :end-header
+    let value = unquote(
+        get_property(emacs, ":value")?
+            .ok_or("Emacs keywords should have a :value")?
+            .as_atom()?,
+    )?;
+    if value != rust.value {
+        this_status = DiffStatus::Bad;
+        message = Some(format!(
+            "Mismatchs keyword values (emacs != rust) {:?} != {:?}",
+            value, rust.value
+        ))
+    }
+
+    Ok(DiffResult {
+        status: this_status,
+        name: emacs_name.to_owned(),
+        message,
+        children: child_status,
+        rust_source: rust.get_source(),
+        emacs_token: emacs,
+    }
+    .into())
+}
+
 fn compare_latex_environment<'s>(
     source: &'s str,
     emacs: &'s Token<'s>,