feat: ergonomic access to site table position column

src/site_table.rs

@@ -297,6 +297,10 @@ impl SiteTable {
         /// Get the position column as a slice
         => position, position_slice_raw, f64);
 
+    pub fn position_column(&self) -> impl crate::TableColumn<SiteId, Position> + '_ {
+        crate::table_column::OpaqueTableColumn(self.position_slice())
+    }
+
     /// Clear all data from the table
     pub fn clear(&mut self) -> Result<i32, TskitError> {
         handle_tsk_return_value!(self.table_.clear())

tests/test_tables.rs

@@ -622,3 +622,11 @@ fn test_edge_table_column_access() {
         assert_eq!(column[edge], tskit::NodeId::from(0));
     }
 }
+
+#[test]
+fn test_site_table_column_access() {
+    let mut table = tskit::SiteTable::default();
+    let site = table.add_row(1.0, None).unwrap();
+    let col = table.position_column();
+    assert_eq!(col[site], 1.0);
+}