* 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.
2026-03-09 04:13:03 +00:00 · 2006-07-09 20:36:33 +00:00
parent b37acfe18c
commit ddc8ede1ab
14 changed files with 229 additions and 84 deletions
--- a/43
+++ b/43
@@ -1,3 +1,46 @@
+2006-07-09  Paul Eggert  <eggert@cs.ucla.edu>
+
+	* 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.
+
+	* src/symlist.c (symbol_list_length): Return int, not unsigned
+	int, since callers expect int.  This may need to get revisited
+	once we have proper integer overflow checking.
+
+	* src/scan-gram.h (gram_scanner_cursor): Remove decl, since this
+	object is now static.
+
+	* src/getargs.c (flags_argmatch): Return void, not int,
+	to pacify ./configure --enable-gcc-warnings.
+
+	* src/flex-scanner.h (STRING_FREE): Don't use FLEX_PREFIX (last_string)
+	since last_string is already defined to FLEX_PREFIX (last_string).
+
 2006-07-09  Akim Demaille  <akim@lrde.epita.fr>

 	Implement --warnings/-W.
--- a/8
+++ b/8
@@ -3,6 +3,12 @@ Bison News

 Changes in version 2.3+:

+* 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.
+  This change is for compatibility with other Yacc implementations,
+  and is required by POSIX.
+
 * Locations columns and lines start at 1.
  In accordance with the GNU Coding Standards and Emacs.

@@ -19,7 +25,7 @@ Changes in version 2.3+:
  `%{ ... %}' syntax.  To generate the pre-prologue, Bison concatenates all
  prologue blocks that you've declared before the first %union.  To generate
  the post-prologue, Bison concatenates all prologue blocks that you've
-  declared after the first %union.  
+  declared after the first %union.

  Previous releases of Bison inserted the pre-prologue into both the header
  file and the code file in all cases except for LALR(1) parsers in C.  In the
--- a/data/glr.c
+++ b/data/glr.c
@@ -175,14 +175,15 @@ m4_define([b4_shared_declarations],

 b4_token_enums(b4_tokens)

-[#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
+[#ifndef YYSTYPE
 ]m4_ifdef([b4_stype],
-[typedef union b4_union_name
-b4_user_stype
-	YYSTYPE;],
-[typedef int YYSTYPE;])[
-# define YYSTYPE_IS_DECLARED 1
-# define YYSTYPE_IS_TRIVIAL 1
+[[typedef union ]b4_union_name[
+]b4_user_stype[
+	YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1]],
+[m4_if(b4_tag_seen_flag, 0,
+[[typedef int YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1]])])[
 #endif

 #if ! defined YYLTYPE && ! defined YYLTYPE_IS_DECLARED
--- a/data/glr.cc
+++ b/data/glr.cc
@@ -288,7 +288,9 @@ namespace ]b4_namespace[
 [    union semantic_type
 b4_user_stype
 	;],
-[    typedef int semantic_type;])[
+[m4_if(b4_tag_seen_flag, 0,
+[[    typedef int semantic_type;]],
+[[    typedef YYSTYPE semantic_type;]])])[
 #else
    typedef YYSTYPE semantic_type;
 #endif
--- a/data/lalr1.cc
+++ b/data/lalr1.cc
@@ -110,7 +110,9 @@ namespace ]b4_namespace[
 [    union semantic_type
 b4_user_stype
 	;],
-[    typedef int semantic_type;])[
+[m4_if(b4_tag_seen_flag, 0,
+[[    typedef int semantic_type;]],
+[[    typedef YYSTYPE semantic_type;]])])[
 #else
    typedef YYSTYPE semantic_type;
 #endif
--- a/data/yacc.c
+++ b/data/yacc.c
@@ -189,13 +189,15 @@ b4_token_enums_defines(b4_tokens)[

 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 ]m4_ifdef([b4_stype],
-[[typedef union ]b4_union_name
-b4_user_stype
-	YYSTYPE;],
-[typedef int YYSTYPE;])[
+[[typedef union ]b4_union_name[
+]b4_user_stype[
+	YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1]],
+[m4_if(b4_tag_seen_flag, 0,
+[[typedef int YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1]])])[
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
 # define YYSTYPE_IS_DECLARED 1
-# define YYSTYPE_IS_TRIVIAL 1
 #endif

 ]b4_locations_if([#if ! defined YYLTYPE && ! defined YYLTYPE_IS_DECLARED
@@ -1499,13 +1501,15 @@ b4_token_enums_defines(b4_tokens)

 [#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 ]m4_ifdef([b4_stype],
-[[typedef union ]b4_union_name
-b4_user_stype
-	YYSTYPE;],
-[typedef int YYSTYPE;])[
+[[typedef union ]b4_union_name[
+]b4_user_stype[
+	YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1]],
+[m4_if(b4_tag_seen_flag, 0,
+[[typedef int YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1]])])[
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
 # define YYSTYPE_IS_DECLARED 1
-# define YYSTYPE_IS_TRIVIAL 1
 #endif

 ]b4_pure_if([],
--- a/doc/bison.texinfo
+++ b/doc/bison.texinfo
@@ -3092,7 +3092,8 @@ the semantic values of all language constructs.  This was true in the
@acronym{RPN} and infix calculator examples (@pxref{RPN Calc, ,Reverse Polish
 Notation Calculator}).

-Bison's default is to use type @code{int} for all semantic values.  To
+Bison normally uses the type @code{int} for semantic values if your
+program uses the same data type for all language constructs.  To
 specify some other type, define @code{YYSTYPE} as a macro, like this:

@example
@@ -3119,9 +3120,11 @@ requires you to do two things:

@itemize @bullet
@item
-Specify the entire collection of possible data types, with the
+Specify the entire collection of possible data types, either by using the
@code{%union} Bison declaration (@pxref{Union Decl, ,The Collection of
-Value Types}).
+Value Types}), or by using a @code{typedef} or a @code{#define} to
+define @code{YYSTYPE} to be a union type whose member names are
+the type tags.

@item
 Choose one of those types for each symbol (terminal or nonterminal) for
@@ -3500,7 +3503,7 @@ since all tokens and groupings always use the same type.

 You can specify the type of locations by defining a macro called
@code{YYLTYPE}, just as you can specify the semantic value type by
-defining @code{YYSTYPE} (@pxref{Value Type}).
+defining a @code{YYSTYPE} macro (@pxref{Value Type}).
 When @code{YYLTYPE} is not defined, Bison uses a default structure type with
 four members:

@@ -3895,6 +3898,35 @@ 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.

+Instead of @code{%union}, you can define and use your own union type
+@code{YYSTYPE} if your grammar contains at least one
+@samp{<@var{type}>} tag.  For example, you can put the following into
+a header file @file{parser.h}:
+
+@example
+@group
+union YYSTYPE @{
+  double val;
+  symrec *tptr;
+@};
+typedef union YYSTYPE YYSTYPE;
+@end group
+@end example
+
+@noindent
+and then your grammar can use the following
+instead of @code{%union}:
+
+@example
+@group
+%@{
+#include "parser.h"
+%@}
+%type <val> expr
+%token <tptr> ID
+@end group
+@end example
+
@node Type Decl
@subsection Nonterminal Symbols
@cindex declaring value types, nonterminals
@@ -4212,10 +4244,13 @@ names defined in the grammar as well as a few other declarations.
 If the parser output file is named @file{@var{name}.c} then this file
 is named @file{@var{name}.h}.

-Unless @code{YYSTYPE} is already defined as a macro, the output header
-declares @code{YYSTYPE}.  Therefore, if you are using a @code{%union}
+For C parsers, the output header declares @code{YYSTYPE} unless unless
+@code{YYSTYPE} is already defined as a macro or you have used a
+@code{<@var{type}>} tag without using @code{%union}.
+Therefore, if you are using a @code{%union}
 (@pxref{Multiple Types, ,More Than One Value Type}) with components that
 require other definitions, or if you have defined a @code{YYSTYPE} macro
+or type definition
 (@pxref{Value Type, ,Data Types of Semantic Values}), you need to
 arrange for these definitions to be propagated to all modules, e.g., by
 putting them in a prerequisite header that is included both by your
@@ -4227,7 +4262,7 @@ Parser}.

 If you have also used locations, the output header declares
@code{YYLTYPE} and @code{yylloc} using a protocol similar to that of
-@code{YYSTYPE} and @code{yylval}.  @xref{Locations, ,Tracking
+the @code{YYSTYPE} macro and @code{yylval}.  @xref{Locations, ,Tracking
 Locations}.

 This output file is normally essential if you wish to put the definition
--- a/src/output.c
+++ b/src/output.c
@@ -590,6 +590,7 @@ prepare (void)
  MUSCLE_INSERT_BOOL ("locations_flag", locations_flag);
  MUSCLE_INSERT_BOOL ("pure_flag", pure_parser);
  MUSCLE_INSERT_BOOL ("synclines_flag", !no_lines_flag);
+  MUSCLE_INSERT_BOOL ("tag_seen_flag", tag_seen);
  MUSCLE_INSERT_BOOL ("yacc_flag", yacc_flag);

  /* File names.  */
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -57,7 +57,7 @@ static char const *char_name (char);
 static void add_param (char const *, char *, location);

 static symbol_class current_class = unknown_sym;
-static uniqstr current_type = 0;
+static uniqstr current_type = NULL;
 static symbol *current_lhs;
 static location current_lhs_location;
 static int current_prec = 0;
@@ -209,7 +209,7 @@ declaration:
  grammar_declaration
 | PROLOGUE
    {
-      prologue_augment (translate_code ($1, @1), @1, typed);
+      prologue_augment (translate_code ($1, @1), @1, union_seen);
    }
 | "%after-header" "{...}"
    {
@@ -322,7 +322,7 @@ grammar_declaration:
    {
      char const *body = $3;

-      if (typed)
+      if (union_seen)
 	{
 	  /* Concatenate the union bodies, turning the first one's
 	     trailing '}' into '\n', and omitting the second one's '{'.  */
@@ -331,7 +331,7 @@ grammar_declaration:
 	  body++;
 	}

-      typed = true;
+      union_seen = true;
      muscle_code_grow ("stype", body, @3);
    }
 ;
@@ -352,6 +352,7 @@ symbol_declaration:
    }
 | "%type" TYPE symbols.1
    {
+      tag_seen = true;
      symbol_list *list;
      for (list = $3; list; list = list->next)
 	symbol_type_set (list->sym, $2, @2);
@@ -382,7 +383,7 @@ precedence_declarator:

 type.opt:
  /* Nothing. */ { current_type = NULL; }
-| TYPE           { current_type = $1; }
+| TYPE           { current_type = $1; tag_seen = true; }
 ;

 /* One or more nonterminals to be %typed. */
@@ -396,6 +397,7 @@ symbol_def:
  TYPE
     {
       current_type = $1;
+       tag_seen = true;
     }
 | id
     {
--- a/src/reader.c
+++ b/src/reader.c
@@ -45,7 +45,10 @@ static bool start_flag = false;
 merger_list *merge_functions;

 /* Was %union seen?  */
-bool typed = false;
+bool union_seen = false;
+
+/* Was a tag seen?  */
+bool tag_seen = false;

 /* Should rules have a default precedence?  */
 bool default_prec = true;
--- 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;
--- a/src/scan-code.l
+++ b/src/scan-code.l
@@ -55,6 +55,9 @@ static void handle_action_dollar (symbol_list *rule, char *cp,
 static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
 static location the_location;
 static location *loc = &the_location;
+
+/* True if an untyped $$ or $n was seen.  */
+static bool untyped_var_seen;
 %}
 /* C and C++ comments in code. */
 %x SC_COMMENT SC_LINE_COMMENT
@@ -262,48 +265,62 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 	++cp;
      *cp = '\0';
      ++cp;
+      if (untyped_var_seen)
+	complain_at (dollar_loc, _("explicit type given in untyped grammar"));
+      tag_seen = true;
    }

  if (*cp == '$')
    {
      if (!type_name)
 	type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
-      if (!type_name && typed)
-	{
-	  if (rule->midrule_parent_rule)
-	    complain_at (dollar_loc,
-			 _("$$ for the midrule at $%d of `%s' has no declared"
-			   " type"),
-			 rule->midrule_parent_rhs_index,
-			 effective_rule->sym->tag);
-	  else
-	    complain_at (dollar_loc, _("$$ of `%s' has no declared type"),
-			 rule->sym->tag);
-	}
+
      if (!type_name)
-	type_name = "";
+	{
+	  if (union_seen | tag_seen)
+	    {
+	      if (rule->midrule_parent_rule)
+		complain_at (dollar_loc,
+			     _("$$ for the midrule at $%d of `%s'"
+			       " has no declared type"),
+			     rule->midrule_parent_rhs_index,
+			     effective_rule->sym->tag);
+	      else
+		complain_at (dollar_loc, _("$$ of `%s' has no declared type"),
+			     rule->sym->tag);
+	    }
+	  else
+	    untyped_var_seen = true;
+	  type_name = "";
+	}
+
      obstack_fgrow1 (&obstack_for_string,
 		      "]b4_lhs_value([%s])[", type_name);
      rule->used = true;
    }
  else
    {
-      long int num;
-      set_errno (0);
-      num = strtol (cp, 0, 10);
-      if (INT_MIN <= num && num <= effective_rule_length && ! get_errno ())
+      long int num = strtol (cp, NULL, 10);
+
+      if (1 - INT_MAX + effective_rule_length <= num
+	  && num <= effective_rule_length)
 	{
 	  int n = num;
-	  if (1-n > max_left_semantic_context)
-	    max_left_semantic_context = 1-n;
-	  if (!type_name && n > 0)
+	  if (max_left_semantic_context < 1 - n)
+	    max_left_semantic_context = 1 - n;
+	  if (!type_name && 0 < n)
 	    type_name =
 	      symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
-	  if (!type_name && typed)
-	    complain_at (dollar_loc, _("$%d of `%s' has no declared type"),
-			 n, effective_rule->sym->tag);
 	  if (!type_name)
-	    type_name = "";
+	    {
+	      if (union_seen | tag_seen)
+		complain_at (dollar_loc, _("$%d of `%s' has no declared type"),
+			     n, effective_rule->sym->tag);
+	      else
+		untyped_var_seen = true;
+	      type_name = "";
+	    }
+
 	  obstack_fgrow3 (&obstack_for_string,
 			  "]b4_rhs_value(%d, %d, [%s])[",
 			  effective_rule_length, n, type_name);
@@ -336,11 +353,10 @@ handle_action_at (symbol_list *rule, char *text, location at_loc)
    obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
  else
    {
-      long int num;
-      set_errno (0);
-      num = strtol (cp, 0, 10);
+      long int num = strtol (cp, NULL, 10);

-      if (INT_MIN <= num && num <= effective_rule_length && ! get_errno ())
+      if (1 - INT_MAX + effective_rule_length <= num
+	  && num <= effective_rule_length)
 	{
 	  int n = num;
 	  obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
@@ -356,9 +372,9 @@ handle_action_at (symbol_list *rule, char *text, location at_loc)
 | Initialize the scanner.  |
 `-------------------------*/

-/* Translate the dollars and ats in \a a, whose location is l.
-   Depending on the \a sc_context (SC_RULE_ACTION, SC_SYMBOL_ACTION,
-   INITIAL), the processing is different.  */
+/* Translate the dollars and ats in \a a, whose location is \a l.  The
+   translation is for \a rule, in the context \a sc_context
+   (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL).  */

 static const char *
 translate_action (int sc_context, symbol_list *rule, const char *a, location l)
--- a/tests/input.at
+++ b/tests/input.at
@@ -107,12 +107,12 @@ c: INT | INT { $]1[ } INT { } INT { };
 d: INT | INT { } INT { $]1[ } INT { };
 e: INT | INT { } INT {  } INT { $]1[ };
 f: INT | INT { } INT {  } INT { $]$[ = $]1[ + $]3[ + $]5[; };
-g: INT | INT { $]$[ } INT { $]$[ } INT { };
-h: INT | INT { $]$[ } INT { $]$[ = $]2[ } INT { };
+g: INT | INT { $<integer>$; } INT { $<integer>$; } INT { };
+h: INT | INT { $<integer>$; } INT { $<integer>$ = $<integer>2; } INT { };
 i: INT | INT INT { } { $]$[ = $]1[ + $]2[; };
 j: INT | INT INT { $<integer>$ = 1; } { $]$[ = $]1[ + $]2[; };
-k: INT | INT INT { $]$[; } { $]$[ = $]3[; } { };
-l: INT | INT { $]$[ = $]1[; } INT { $]$[ = $]2[ + $]3[; } INT { $]$[ = $]4[ + $]5[; };]]m4_ifval($1, [
+k: INT | INT INT { $<integer>$; } { $<integer>$ = $<integer>3; } { };
+l: INT | INT { $<integer>$ = $<integer>1; } INT { $<integer>$ = $<integer>2 + $<integer>3; } INT { $<integer>$ = $<integer>4 + $<integer>5; };]]m4_ifval($1, [
 _AT_UNUSED_VALUES_DECLARATIONS])
 )

@@ -131,22 +131,22 @@ input.y:14.10-35: warning: unused value: $]5[
 input.y:15.10-36: warning: unset value: $]$[
 input.y:15.10-36: warning: unused value: $]3[
 input.y:15.10-36: warning: unused value: $]5[
-input.y:17.10-38: warning: unset value: $]$[
-input.y:17.10-38: warning: unused value: $]1[
-input.y:17.10-38: warning: unused value: $]2[
-input.y:17.10-38: warning: unused value: $]3[
-input.y:17.10-38: warning: unused value: $]4[
-input.y:17.10-38: warning: unused value: $]5[
-input.y:18.10-43: warning: unset value: $]$[
-input.y:18.10-43: warning: unused value: $]1[
-input.y:18.10-43: warning: unused value: $]3[
-input.y:18.10-43: warning: unused value: $]4[
-input.y:18.10-43: warning: unused value: $]5[
+input.y:17.10-58: warning: unset value: $]$[
+input.y:17.10-58: warning: unused value: $]1[
+input.y:17.10-58: warning: unused value: $]2[
+input.y:17.10-58: warning: unused value: $]3[
+input.y:17.10-58: warning: unused value: $]4[
+input.y:17.10-58: warning: unused value: $]5[
+input.y:18.10-72: warning: unset value: $]$[
+input.y:18.10-72: warning: unused value: $]1[
+input.y:18.10-72: warning: unused value: $]3[
+input.y:18.10-72: warning: unused value: $]4[
+input.y:18.10-72: warning: unused value: $]5[
 input.y:20.10-55: warning: unused value: $]3[
-input.y:21.10-41: warning: unset value: $]$[
-input.y:21.10-41: warning: unused value: $]1[
-input.y:21.10-41: warning: unused value: $]2[
-input.y:21.10-41: warning: unused value: $]4[
+input.y:21.10-68: warning: unset value: $]$[
+input.y:21.10-68: warning: unused value: $]1[
+input.y:21.10-68: warning: unused value: $]2[
+input.y:21.10-68: warning: unused value: $]4[
 ]])])


--- a/tests/regression.at
+++ b/tests/regression.at
@@ -49,6 +49,33 @@ AT_CLEANUP



+## ----------------- ##
+## YYSTYPE typedef.  ##
+## ----------------- ##
+
+AT_SETUP([YYSTYPE typedef])
+
+AT_DATA_GRAMMAR([input.y],
+[[%{
+void yyerror (char const *);
+int yylex (void);
+typedef union { char const *val; } YYSTYPE;
+%}
+
+%type <val> program
+
+%%
+
+program: { $$ = ""; };
+]])
+
+AT_CHECK([bison -o input.c input.y])
+AT_COMPILE([input.o], [-c input.c])
+
+AT_CLEANUP
+
+
+
 ## ------------------------------------- ##
 ## Early token definitions with --yacc.  ##
 ## ------------------------------------- ##