lib9p: Fixup the idl README

1 files changed, 14 insertions, 5 deletions

diff --git a/lib9p/idl/0000-README.md b/lib9p/idl/0000-README.md
index 86862b7..a541006 100644
--- a/lib9p/idl/0000-README.md
+++ b/lib9p/idl/0000-README.md
@@ -1,7 +1,7 @@
 <!--
   lib9p/idl/0000-README.md - Overview of 9P protocol definitions
 
-  Copyright (C) 2024  Luke T. Shumaker <lukeshu@lukeshu.com>
+  Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
   SPDX-License-Identifier: AGPL-3.0-or-later
   -->
 
@@ -35,7 +35,7 @@ bitfields,
 
 structures,
 
-	struct STRUCTNAME = "FILENAME[FIELDTYPE]..."
+	struct STRUCTNAME = "FIELDNAME[FIELDTYPE]..."
 
 and messages (which are a special-case of structures).
 
@@ -44,8 +44,17 @@ and messages (which are a special-case of structures).
 Struct fields that have numeric types (either primitives or `num`
 types) can add to their type `,val=` and/or `,max=` to specify what
 the exact value must be and/or what the maximum (inclusive) value is.
+A field that is repeated a variable number of times be wrapped in
+parenthesis and prefixed with the fieldname containing that count:
+`OTHERFIELDNAME*(FIELDNAME[FIELDTYPE])`.
 
 `,val=` and `,max` take a string of `+`/`-` tokens and values; a value
-can either be a decimal numeric constant (eg: `107`), the `&fieldname`
-to refer to the offset of a field name in that struct, or the special
-value `end` to refer to the offset of the end of the struct.
+can be
+ - a decimal numeric constant (eg: `107`),
+ - `&fieldname` to refer to the offset of a field name in that struct,
+ - the special value `end` to refer to the offset of the end of the
+   struct,
+
+A parser for this syntax is given in `__init__.py`.  However,
+`__init__.py` places the somewhat arbitrary undocumented restrictions
+on fields referenced as the count for a repeated field.