Move the Date struct into types and implement a get_property_numeric.

src/compare/diff.rs

@@ -10,6 +10,7 @@ use super::sexp::Token;
 use super::util::compare_standard_properties;
 use super::util::get_property;
 use super::util::get_property_boolean;
+use super::util::get_property_numeric;
 use super::util::get_property_quoted_string;
 use super::util::get_property_unquoted_atom;
 use crate::types::AngleLink;
@@ -2163,6 +2164,21 @@ fn compare_timestamp<'b, 's>(
         ));
     }
 
+    // Compare start
+    let year_start: Option<u16> = get_property_unquoted_atom(emacs, ":year-start")?
+        .map(|val| val.parse())
+        .map_or(Ok(None), |r| r.map(Some))?;
+    let month_start: Option<u8> = get_property_unquoted_atom(emacs, ":month-start")?
+        .map(|val| val.parse())
+        .map_or(Ok(None), |r| r.map(Some))?;
+    let day_of_month_start: Option<u8> = get_property_unquoted_atom(emacs, ":day-start")?
+        .map(|val| val.parse())
+        .map_or(Ok(None), |r| r.map(Some))?;
+
+    let year_end = get_property_numeric::<u16>(emacs, ":year-end")?;
+
+    // Compare end
+
     // TODO: Compare :year-start :month-start :day-start :hour-start :minute-start :year-end :month-end :day-end :hour-end :minute-end :repeater-type :repeater-value :repeater-unit :warning-type :warning-value :warning-unit
     //
     // :type unquoted atom either diary, active, inactive, active-range, or inactive-range.

src/compare/util.rs

@@ -1,3 +1,5 @@
+use std::str::FromStr;
+
 use super::elisp_fact::GetElispFact;
 use super::sexp::Token;
 use crate::compare::sexp::unquote;
@@ -234,3 +236,23 @@ pub(crate) fn get_property_boolean<'b, 's, 'x>(
         .unwrap_or("nil")
         != "nil")
 }
+
+/// Get a named property containing an unquoted numeric value.
+///
+/// Returns None if key is not found.
+pub(crate) fn get_property_numeric<'b, 's, 'x, N: FromStr>(
+    emacs: &'b Token<'s>,
+    key: &'x str,
+) -> Result<Option<N>, Box<dyn std::error::Error>>
+where
+    <N as FromStr>::Err: std::error::Error,
+    <N as FromStr>::Err: 'static,
+{
+    let foo = get_property(emacs, key)?
+        .map(Token::as_atom)
+        .map_or(Ok(None), |r| r.map(Some))?;
+    let bar = foo
+        .map(|val| val.parse::<N>())
+        .map_or(Ok(None), |r| r.map(Some))?;
+    Ok(bar)
+}