From 791aaf88cca53036d19ad2e247c783744ccf3837 Mon Sep 17 00:00:00 2001
From: Bart Schaefer <schaefer@zsh.org>
Date: Sun, 4 Feb 2024 20:46:49 -0800
Subject: [PATCH] cf. users/29635: additional detail of parameter expansion in
 math context.

---
 ChangeLog        | 3 +++
 Doc/Zsh/arith.yo | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index c553b02cf..964eeef23 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2024-02-04  Bart Schaefer  <schaefer@zsh.org>
 
+	* unposted (cf. users/29635): Doc/Zsh/arith.yo: additional detail
+	of parameter expansion in math context.
+
 	* 52521: Etc/BUGS: mapfile handling of empty/unreadable files
 
 2024-02-04  Mikael Magnusson  <mikachu@gmail.com>
diff --git a/Doc/Zsh/arith.yo b/Doc/Zsh/arith.yo
index bc3e35ad5..9f5298821 100644
--- a/Doc/Zsh/arith.yo
+++ b/Doc/Zsh/arith.yo
@@ -206,6 +206,11 @@ example,
 example(((val2 = val1 * 2)))
 
 assigns twice the value of tt($val1) to the parameter named tt(val2).
+If the expansion of tt($val1) is text rather than a number, then when
+tt(val1) is referenced that text is itself evaluated as a math expression
+as if surrounded by parentheses `tt(LPAR()$val1)tt(RPAR())'.  Expansion
+continues until there are no more parameter references, a number has
+resulted, or an expression error occurs.
 
 An internal integer representation of a named parameter
 can be specified with the tt(integer) builtin.