diff --git a/preserves-path.md b/preserves-path.md
index 40cc197..5db1fd4 100644
--- a/preserves-path.md
+++ b/preserves-path.md
@@ -99,6 +99,17 @@ Filters: narrow down a selection without moving
         dict
         embedded
 
+Design choice: Which regular expression dialect to choose? [CDDL (RFC
+8610) goes for XML Schema regular
+expressions](https://www.rfc-editor.org/rfc/rfc8610.html#section-3.8.3),
+which seems like a very sensible choice. The discussion in section
+3.8.3 of RFC 8610 makes some good points. A couple of things that
+occurred to me: (1) the dialect should be backreference-free, allowing
+matching by "[text-directed
+engines](https://www.regular-expressions.info/engine.html)"; (2) it
+should be very widely implemented; (3) it should cover regular
+languages and no more; (4) it should be easy to implement.
+
 ## Transformers
 
 e.g. stringify results; sequenceify results (see "+" operator); setify