Add reflector comments to 4017

Author: jwakely

xml/issue4017.xml

@@ -61,6 +61,27 @@ The following demo shows Barry Revzin's implementation from <paper num="P2210"/>
 Set priority to 3 after reflector poll.
 </p>
 
+<note>2024-03; Reflector comments</note>
+<p>
+"For `split`, we need to adjust the definition of `end()` for the
+`common_range` case
+(which may require introducing a new constructor to the iterator);
+right now it would compare `ranges::end(base_)` against a value-initialized
+iterator, which is not in the domain of `==`.
+For `lazy_split`, we need to also change the non-forward overload."
+</p>
+<p>
+"What should splitting an empty range on an empty pattern produce?
+Right now the behavior is that splitting a range of N &gt; 0 elements
+with an empty pattern produces a range of N single-element ranges.
+I suppose you can argue that an empty pattern matches between adjacent elements
+but not at the start or end, so that an empty range, like a single-element range,
+contains 0 delimiters so should produce a range of one empty range.
+But it's also at least arguable that this should produce an empty range instead,
+so that we maintain the N element &lt;-&gt; N subrange
+and 1 element per subrange invariant.
+</p>
+
 </discussion>
 
 <resolution>