From 37263f983ab291163608e95da8db1de93d94bf71 Mon Sep 17 00:00:00 2001
From: timofey <tim@ongoteam.yaconnect.com>
Date: Tue, 1 Aug 2023 20:00:32 +0000
Subject: [PATCH] simplify `n_subset_of_n`

---
 src/flow/traversible/algorithms/subset.rs | 50 ++++++++++++++---------
 1 file changed, 31 insertions(+), 19 deletions(-)

diff --git a/src/flow/traversible/algorithms/subset.rs b/src/flow/traversible/algorithms/subset.rs
index 8c2ae9b..0309864 100644
--- a/src/flow/traversible/algorithms/subset.rs
+++ b/src/flow/traversible/algorithms/subset.rs
@@ -94,6 +94,22 @@ impl<'a, T: 'a + MonadFail<'a, ()>, A: 'a + Clone, D: 'a + PartialEq> SubsetCont
     }
 }
 
+fn outside_l<A>(comparator: &dyn Comparator<A>, k_l: &Option<A>, k_super: &A) -> bool {
+    if let Some(a_l) = k_l {
+        comparator.compare(a_l, k_super) == Comparison::R
+    } else {
+        false
+    }
+}
+
+fn outside_r<A>(comparator: &dyn Comparator<A>, k_r: &Option<A>, k_super: &A) -> bool {
+    if let Some(a_r) = k_r {
+        comparator.compare(a_r, k_super) == Comparison::L
+    } else {
+        false
+    }
+}
+
 pub fn n_subset_of_n<'a, T: MonadFail<'a, ()>, A: 'a + Clone, D: 'a + PartialEq>(
     comparator: &'a dyn Comparator<A>,
     n_subset: Rc<dyn TraversibleBinaryNode<'a, T, A, D>>,
@@ -102,27 +118,23 @@ pub fn n_subset_of_n<'a, T: MonadFail<'a, ()>, A: 'a + Clone, D: 'a + PartialEq>
     k_r: Option<A>,
 ) -> T::F<()> {
     let (t_superl, t_superr, k_super) = n_superset.split();
-    if let Some(ref a_l) = k_l {
-        if let Comparison::R = comparator.compare(a_l, &k_super) {
-            return t_subset_of_t(comparator, n_subset.to_tree(), t_superr, k_l, k_r);
+    if outside_l(comparator, &k_l, &k_super) {
+        t_subset_of_t(comparator, n_subset.to_tree(), t_superr, k_l, k_r)
+    } else if outside_r(comparator, &k_r, &k_super) {
+        t_subset_of_t(comparator, n_subset.to_tree(), t_superl, k_l, k_r)
+    } else {
+        SubsetContext {
+            comparator,
+            n_subset,
+            n_superset,
+            k_l,
+            k_r,
+            t_superl,
+            t_superr,
+            k_super,
         }
+        .test()
     }
-    if let Some(ref a_r) = k_r {
-        if let Comparison::L = comparator.compare(a_r, &k_super) {
-            return t_subset_of_t(comparator, n_subset.to_tree(), t_superl, k_l, k_r);
-        }
-    }
-    SubsetContext {
-        comparator,
-        n_subset,
-        n_superset,
-        k_l,
-        k_r,
-        t_superl,
-        t_superr,
-        k_super,
-    }
-    .test()
 }
 
 pub fn r_subset_of_r<'a, T: MonadFail<'a, ()>, A: 'a + Clone, D: 'a + PartialEq>(