api.value.type: diagnose guaranteed failure with --yacc

[bison.git] / doc / bison.texi

diff --git a/doc/bison.texi b/doc/bison.texi
index 2ed10c2f7c5af0c50e629234002f3bb482d8ae57..198403feacd5f164c09ae67df4ef8fe374d4652d 100644 (file)
--- a/doc/bison.texi
+++ b/doc/bison.texi
@@ -3795,6 +3795,11 @@ yylval.TOK_INT = 42;
 return TOK_INT;
 @end example
 
+This Bison extension cannot work if @code{%yacc} (or
+@option{-y}/@option{--yacc}) is enabled, as POSIX mandates that Yacc
+generate tokens as macros (e.g., @samp{#define INT 258}, or @samp{#define
+TOK_INT 258}).
+
 This feature is new, and user feedback would be most welcome.
 
 A similar feature is provided for C++ that in addition overcomes C++
@@ -4990,10 +4995,8 @@ For example:
 
 @example
 %union @{ char *string; @}
-%token <string> STRING1
-%token <string> STRING2
-%type  <string> string1
-%type  <string> string2
+%token <string> STRING1 STRING2
+%type  <string> string1 string2
 %union @{ char character; @}
 %token <character> CHR
 %type  <character> chr
@@ -5119,10 +5122,8 @@ For example:
 
 @example
 %union @{ char *string; @}
-%token <string> STRING1
-%token <string> STRING2
-%type  <string> string1
-%type  <string> string2
+%token <string> STRING1 STRING2
+%type  <string> string1 string2
 %union @{ char character; @}
 %token <character> CHR
 %type  <character> chr