2006-01-18 Paul Eggert <eggert@cs.ucla.edu>
+ * NEWS: Document the fact that multiple %unions are now allowed.
+ * doc/bison.texinfo (Union Decl): Likewise.
+
* Makefile.maint: Merge with coreutils Makefile.maint.
(CVS_LIST): Use build-aux version if available.
(VERSION_REGEXP): New macro.
Changes in version 2.1a:
+* Bison now allows multiple %union declarations, and concatenates
+ their contents together.
+
* New warning: unused values
Typed right-hand side symbols whose value are not used are reported.
For instance:
-----
-Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
-Free Software Foundation, Inc.
+Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
+2004, 2005, 2006 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
@end group
@end example
+@noindent
specifies the union tag @code{value}, so the corresponding C type is
@code{union value}. If you do not specify a tag, it defaults to
@code{YYSTYPE}.
+As another extension to @acronym{POSIX}, you may specify multiple
+@code{%union} declarations; their contents are concatenated. However,
+only the first @code{%union} declaration can specify a tag.
+
Note that, unlike making a @code{union} declaration in C, you need not write
a semicolon after the closing brace.