feat: add left,right,outer join module examples

hydroflow/examples/modules_outer_join/full_outer_join.hf

@@ -0,0 +1,23 @@
+lhs = mod[0] -> tee();
+rhs = mod[1] -> tee();
+
+lhs -> [0]joined;
+rhs -> [1]joined;
+
+joined = join() -> map(|(k, (lhs, rhs))| (k, (Some(lhs), Some(rhs)))) -> combined;
+
+lhs -> [pos]missed_lhs;
+rhs -> map(|(k, _v)| k) -> [neg]missed_lhs;
+
+missed_lhs = anti_join()
+    -> map(|(k, v)| (k, (Some(v), None)))
+    -> combined;
+
+rhs -> [pos]missed_rhs;
+lhs -> map(|(k, _v)| k) -> [neg]missed_rhs;
+
+missed_rhs = anti_join()
+    -> map(|(k, v)| (k, (None, Some(v))))
+    -> combined;
+
+combined = union() -> mod;

hydroflow/examples/modules_outer_join/left_outer_join.hf

@@ -0,0 +1,16 @@
+lhs = mod[0] -> tee();
+rhs = mod[1] -> tee();
+
+lhs -> [0]joined;
+rhs -> [1]joined;
+
+joined = join() -> map(|(k, (lhs, rhs))| (k, (lhs, Some(rhs)))) -> combined;
+
+lhs -> [pos]missed;
+rhs -> map(|(k, _v)| k) -> [neg]missed;
+
+missed = anti_join()
+    -> map(|(k, v)| (k, (v, None)))
+    -> combined;
+
+combined = union() -> mod;

hydroflow/examples/modules_outer_join/main.rs

@@ -0,0 +1,30 @@
+use hydroflow::hydroflow_syntax;
+
+pub fn main() {
+    let mut df = hydroflow_syntax! {
+        lhs = source_iter([("a", 0), ("b", 1)]) -> tee();
+        rhs = source_iter([("a", 2), ("c", 3)]) -> tee();
+
+        lhs -> [0]inner_join;
+        rhs -> [1]inner_join;
+        inner_join = join() -> assert_eq([("a", (0, 2))]);
+
+        lhs -> [0]left_outer_join;
+        rhs -> [1]left_outer_join;
+        left_outer_join = import!("left_outer_join.hf") -> assert_eq([("a", (0, Some(2))), ("b", (1, None))]);
+
+        lhs -> [0]right_outer_join;
+        rhs -> [1]right_outer_join;
+        right_outer_join = import!("right_outer_join.hf") -> assert_eq([("a", (Some(0), 2)), ("c", (None, 3))]);
+
+        lhs -> [0]full_outer_join;
+        rhs -> [1]full_outer_join;
+        full_outer_join = import!("full_outer_join.hf") -> assert_eq([("a", (Some(0), Some(2))), ("b", (Some(1), None)), ("c", (None, Some(3)))]);
+    };
+    df.run_available();
+}
+
+#[test]
+fn test() {
+    main();
+}

hydroflow/examples/modules_outer_join/right_outer_join.hf

@@ -0,0 +1,6 @@
+// flip the lhs and rhs
+mod[0] -> [1]left_outer_join;
+mod[1] -> [0]left_outer_join;
+
+// flip them back
+left_outer_join = import!("left_outer_join.hf") -> map(|(k, (v1, v2))| (k, (v2, v1))) -> mod;