variables: accept dashes.

[bison.git] / doc / bison.texinfo

diff --git a/doc/bison.texinfo b/doc/bison.texinfo
index c52d7b8a14da96773d561265f3024bd12659f3d2..46c95f01c1ac1b9e792f0b767b343901af4f7e6a 100644 (file)
--- a/doc/bison.texinfo
+++ b/doc/bison.texinfo
@@ -3051,8 +3051,12 @@ A @dfn{nonterminal symbol} stands for a class of syntactically
 equivalent groupings.  The symbol name is used in writing grammar rules.
 By convention, it should be all lower case.
 
-Symbol names can contain letters, digits (not at the beginning),
-underscores and periods.  Periods make sense only in nonterminals.
+Symbol names can contain letters, underscores, period, and (not at the
+beginning) digits and dashes.  Dashes in symbol names are a GNU
+extension, incompatible with @acronym{POSIX} Yacc.  Terminal symbols
+that contain periods or dashes make little sense: since they are not
+valid symbols (in most programming languages) they are not exported as
+token names.
 
 There are three ways of writing terminal symbols in the grammar: