inner_sort_by: comments

1 files changed, 6 insertions, 3 deletions

diff --git a/cli/src/main.rs b/cli/src/main.rs
index e405e48..3ffbe88 100644
--- a/cli/src/main.rs
+++ b/cli/src/main.rs
@@ -161,15 +161,16 @@ fn inner_sort_by<T, F>(v: &mut [T], cmps: &mut [F])
 where
     F: FnMut(&T, &T) -> Ordering,
 {
-    // Early out
-    if v.len() < 2 || cmps.is_empty() {
+    if v.is_empty() || cmps.is_empty() {
         return;
     }
 
+    // Sort the slice using the first comparison.
     v.sort_by(&mut cmps[0]);
 
+    // Find ranges of consecutive equal items according to the first comparison.
     let mut ranges = Vec::new();
-    let mut lower = 0; // Lower bound of current equal range
+    let mut lower = 0; // Lower bound of current equal range.
     for i in 0..v.len() {
         if cmps[0](&v[i], &v[lower]) != Ordering::Equal {
             ranges.push(lower..i);
@@ -177,6 +178,8 @@ where
         }
     }
 
+    // If we still have comparisons to use, sort the ranges of consecutive items recursively.
+    // The recursion ensures that ranges of equal items aren't mixed between comparisons further down.
     if cmps.len() != 1 {
         for range in ranges {
             inner_sort_by(&mut v[range], &mut cmps[1..]);