* NEWS: Instead of %union, you can define and use your own union type

YYSTYPE if your grammar contains at least one <type> tag.
Your YYSTYPE need not be a macro; it can be a typedef.
* doc/bison.texinfo (Value Type, Multiple Types, Location Type):
(Union Decl, Decl Summary): Document this.
* data/glr.c (YYSTYPE): Implement this.
* data/glr.cc (YYSTYPE): Likewise.
* data/lalr1.cc (YYSTYPE): Likewise.
* data/yacc.c (YYSTYPE): Likewise.
* src/output.c (prepare): Output tag_seen_flag.
* src/parse-gram.y (declaration, grammar_declaration):
Use 'union_seen' rather than 'typed' to determine whether
%union has been seen, since grammars can now be typed without
%union.
(symbol_declaration, type.opt, symbol_def):
Keep track of whether a tag has been seen.
* src/reader.c (union_seen, tag_seen): New vars.
(typed): remove.
* src/reader.h (union_seen, tag_seen, typed): Likewise.
* src/scan-code.l (untyped_var_seen): New variable.
(handle_action_dollar): Adjust to above changes.
(handle_action_dollar, handle_action_at):
Improve overflow checking for outlandish numbers.
* tests/input.at (AT_CHECK_UNUSED_VALUES): Redo test to
avoid new diagnostics generated by above changes.
* tests/regression.at (YYSTYPE typedef): Add test to check
for type tags without %union.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/reader.h b/src/reader.h
index 52c059c4..43985965 100644
--- a/src/reader.h
+++ b/src/reader.h
@@ -59,7 +59,10 @@ void free_merger_functions (void);
 extern merger_list *merge_functions;
 
 /* Was %union seen?  */
-extern bool typed;
+extern bool union_seen;
+
+/* Was a tag seen?  */
+extern bool tag_seen;
 
 /* Should rules have a default precedence?  */
 extern bool default_prec;