Document how `%define "var" "value"' is not M4-friendly.

[bison.git] / src / parse-gram.y

diff --git a/src/parse-gram.y b/src/parse-gram.y
index caa3d3098de65f60f493ae23fe0da154b7a68cef..f5015e2487663a51f39f0229bb39b042041c8b88 100644 (file)
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -533,6 +533,8 @@ rhs:
 | variable and content.opt.  |
 `---------------------------*/
 
+/* The STRING form of variable is deprecated and is not M4-friendly.
+   For example, M4 fails for `%define "[" "value"'.  */
 variable:
   ID
 | STRING { $$ = uniqstr_new ($1); }