Only include sexp module if compare feature is enabled.

src/context/context.rs

@@ -28,6 +28,7 @@ pub(crate) enum ContextElement<'r, 's> {
     ConsumeTrailingWhitespace(bool),
 
     /// This is just here to use the 's lifetime until I'm sure we can eliminate it from ContextElement.
+    #[allow(dead_code)]
     Placeholder(PhantomData<&'s str>),
 }
 

src/parser/mod.rs

@@ -37,6 +37,7 @@ mod property_drawer;
 mod radio_link;
 mod regular_link;
 mod section;
+#[cfg(feature = "compare")]
 pub mod sexp;
 mod statistics_cookie;
 mod subscript_and_superscript;