Compare standard properties.

src/compare/mod.rs

@@ -20,4 +20,5 @@ pub use sexp::Token;
 pub(crate) use util::get_emacs_standard_properties;
 pub(crate) use util::get_property;
 pub(crate) use util::get_property_quoted_string;
+pub(crate) use util::maybe_token_to_usize;
 pub(crate) use util::EmacsStandardProperties;

src/compare/util.rs

@@ -203,7 +203,7 @@ pub(crate) fn get_emacs_standard_properties(
     })
 }
 
-fn maybe_token_to_usize(
+pub(crate) fn maybe_token_to_usize(
     token: Option<&Token<'_>>,
 ) -> Result<Option<usize>, Box<dyn std::error::Error>> {
     Ok(token