diff -r 06f8b072f28e -r 8c5eedb6c983 src/Pure/General/bytes.ML
--- a/src/Pure/General/bytes.ML	Tue Jun 21 15:56:31 2022 +0200
+++ b/src/Pure/General/bytes.ML	Tue Jun 21 16:03:00 2022 +0200
@@ -33,6 +33,8 @@
 structure Bytes: BYTES =
 struct
 
+(* primitive operations *)
+
 val chunk_size = 1024 * 1024;
 
 abstype T = Bytes of
@@ -71,6 +73,9 @@
 
 end;
 
+
+(* derived operations *)
+
 fun append bytes1 bytes2 =  (*left-associative*)
   if is_empty bytes1 then bytes2
   else if is_empty bytes2 then bytes1
@@ -97,6 +102,9 @@
 val read = File.open_input read_stream;
 val write = File.open_output write_stream;
 
+
+(* ML pretty printing *)
+
 val _ =
   ML_system_pp (fn _ => fn _ => fn bytes =>
     PolyML.PrettyString ("Bytes {length = " ^ string_of_int (length bytes) ^ "}"))