diff --git a/lib-nested-core/src/editors/product/segment.rs b/lib-nested-core/src/editors/product/segment.rs
index 0b223f5..a9c9318 100644
--- a/lib-nested-core/src/editors/product/segment.rs
+++ b/lib-nested-core/src/editors/product/segment.rs
@@ -19,7 +19,10 @@ use {
 
 #[derive(Clone)]
 pub enum ProductEditorSegment {
+    /// Terminal Node, i.e. literal, immutable string
     T( String, usize ),
+
+    /// Nonterminal Node, i.e. sub-editor for type t
     N {
         t: TypeTerm,
         editor: Option<NestedNode>,