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 5bf6694942f7ee54a67e1d59fa94f4cc96367ac0..5af473c750dba0711bec3ae41165ff16e6738b35 100644 (file)
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -545,6 +545,8 @@ 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); }