feat: access to ergonomic edge table columns (#730)

Author: molpopgen

src/edge_table.rs

@@ -358,6 +358,22 @@ impl EdgeTable {
         /// Get the child column as a slice of the underlying integer type
         => child, child_slice_raw, ll_bindings::tsk_id_t);
 
+    pub fn parent_column(&self) -> crate::EdgeTableColumn<crate::NodeId> {
+        crate::EdgeTableColumn::new(self.parent_slice())
+    }
+
+    pub fn child_column(&self) -> crate::EdgeTableColumn<crate::NodeId> {
+        crate::EdgeTableColumn::new(self.child_slice())
+    }
+
+    pub fn left_column(&self) -> crate::EdgeTableColumn<Position> {
+        crate::EdgeTableColumn::new(self.left_slice())
+    }
+
+    pub fn right_column(&self) -> crate::EdgeTableColumn<Position> {
+        crate::EdgeTableColumn::new(self.right_slice())
+    }
+
     /// Clear all data from the table
     pub fn clear(&mut self) -> Result<i32, TskitError> {
         handle_tsk_return_value!(self.table_.clear())

src/lib.rs

@@ -117,7 +117,7 @@ pub use site_table::{SiteTable, SiteTableRow};
 pub use sys::flags::*;
 pub use sys::NodeTraversalOrder;
 pub use table_collection::TableCollection;
-pub use table_column::NodeTableColumn;
+pub use table_column::{EdgeTableColumn, NodeTableColumn};
 pub use traits::IndividualLocation;
 pub use traits::IndividualParents;
 pub use trees::{Tree, TreeSequence};

src/table_column.rs

@@ -58,3 +58,4 @@ macro_rules! make_table_column {
 }
 
 make_table_column!(NodeTableColumn, NodeId);
+make_table_column!(EdgeTableColumn, EdgeId);

tests/test_tables.rs

@@ -588,3 +588,33 @@ fn test_node_table_column_access() {
         );
     }
 }
+
+#[test]
+fn test_edge_table_column_access() {
+    let mut table = tskit::EdgeTable::default();
+    let edge = table.add_row(0., 10., 1, 0).unwrap();
+
+    {
+        let column = table.left_column();
+        assert_eq!(column[edge], 0.0);
+        assert_eq!(column[edge], tskit::Position::from(0.));
+    }
+
+    {
+        let column = table.right_column();
+        assert_eq!(column[edge], 10.0);
+        assert_eq!(column[edge], tskit::Position::from(10.0));
+    }
+
+    {
+        let column = table.parent_column();
+        assert_eq!(column[edge], 1);
+        assert_eq!(column[edge], tskit::NodeId::from(1));
+    }
+
+    {
+        let column = table.child_column();
+        assert_eq!(column[edge], 0);
+        assert_eq!(column[edge], tskit::NodeId::from(0));
+    }
+}