* bootstrap (gnulib_modules): Add strverscmp.

* lib/.cvsignore: Add strverscmp.c, strverscmp.h.
* m4/.cvsignore: Add strverscmp.m4.
* src/parse-gram.y (%require): New token, new rule.
(version_check): New.
* src/scan-gram.l (%require): Adjust.
* tests/input.at (AT_REQUIRE): New.
Use it.
* doc/bison.texinfo (Require Decl): New.
(Calc++ Parser): Use %require.

src/parse-gram.h

@@ -63,21 +63,22 @@
      PERCENT_OUTPUT = 288,
      PERCENT_PARSE_PARAM = 289,
      PERCENT_PURE_PARSER = 290,
-     PERCENT_SKELETON = 291,
-     PERCENT_START = 292,
-     PERCENT_TOKEN_TABLE = 293,
-     PERCENT_VERBOSE = 294,
-     PERCENT_YACC = 295,
-     TYPE = 296,
-     EQUAL = 297,
-     SEMICOLON = 298,
-     PIPE = 299,
-     ID = 300,
-     ID_COLON = 301,
-     PERCENT_PERCENT = 302,
-     PROLOGUE = 303,
-     EPILOGUE = 304,
-     BRACED_CODE = 305
+     PERCENT_REQUIRE = 291,
+     PERCENT_SKELETON = 292,
+     PERCENT_START = 293,
+     PERCENT_TOKEN_TABLE = 294,
+     PERCENT_VERBOSE = 295,
+     PERCENT_YACC = 296,
+     TYPE = 297,
+     EQUAL = 298,
+     SEMICOLON = 299,
+     PIPE = 300,
+     ID = 301,
+     ID_COLON = 302,
+     PERCENT_PERCENT = 303,
+     PROLOGUE = 304,
+     EPILOGUE = 305,
+     BRACED_CODE = 306
    };
 #endif
 /* Tokens.  */
@@ -115,27 +116,28 @@
 #define PERCENT_OUTPUT 288
 #define PERCENT_PARSE_PARAM 289
 #define PERCENT_PURE_PARSER 290
-#define PERCENT_SKELETON 291
-#define PERCENT_START 292
-#define PERCENT_TOKEN_TABLE 293
-#define PERCENT_VERBOSE 294
-#define PERCENT_YACC 295
-#define TYPE 296
-#define EQUAL 297
-#define SEMICOLON 298
-#define PIPE 299
-#define ID 300
-#define ID_COLON 301
-#define PERCENT_PERCENT 302
-#define PROLOGUE 303
-#define EPILOGUE 304
-#define BRACED_CODE 305
+#define PERCENT_REQUIRE 291
+#define PERCENT_SKELETON 292
+#define PERCENT_START 293
+#define PERCENT_TOKEN_TABLE 294
+#define PERCENT_VERBOSE 295
+#define PERCENT_YACC 296
+#define TYPE 297
+#define EQUAL 298
+#define SEMICOLON 299
+#define PIPE 300
+#define ID 301
+#define ID_COLON 302
+#define PERCENT_PERCENT 303
+#define PROLOGUE 304
+#define EPILOGUE 305
+#define BRACED_CODE 306
 
 
 
 
 #if ! defined (YYSTYPE) && ! defined (YYSTYPE_IS_DECLARED)
-#line 79 "../../src/parse-gram.y"
+#line 82 "../../src/parse-gram.y"
 typedef union YYSTYPE {
   symbol *symbol;
   symbol_list *list;
@@ -145,7 +147,7 @@ typedef union YYSTYPE {
   uniqstr uniqstr;
 } YYSTYPE;
 /* Line 1505 of yacc.c.  */
-#line 149 "../../src/parse-gram.h"
+#line 151 "../../src/parse-gram.h"
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
 # define YYSTYPE_IS_DECLARED 1
 # define YYSTYPE_IS_TRIVIAL 1

src/parse-gram.y

@@ -32,6 +32,7 @@
 #include "quotearg.h"
 #include "reader.h"
 #include "symlist.h"
+#include "strverscmp.h"
 
 #define YYLLOC_DEFAULT(Current, Rhs, N)  (Current) = lloc_default (Rhs, N)
 static YYLTYPE lloc_default (YYLTYPE const *, int);
@@ -39,6 +40,8 @@ static YYLTYPE lloc_default (YYLTYPE const *, int);
 #define YY_LOCATION_PRINT(File, Loc) \
           location_print (File, Loc)
 
+static void version_check (location const *loc, char const *version);
+
 /* Request detailed syntax error messages, and pass them to GRAM_ERROR.
    FIXME: depends on the undocumented availability of YYLLOC.  */
 #undef  yyerror
@@ -133,6 +136,7 @@ static int current_prec = 0;
   PERCENT_OUTPUT          "%output"
   PERCENT_PARSE_PARAM     "%parse-param {...}"
   PERCENT_PURE_PARSER     "%pure-parser"
+  PERCENT_REQUIRE 	  "%require"
   PERCENT_SKELETON        "%skeleton"
   PERCENT_START           "%start"
   PERCENT_TOKEN_TABLE     "%token-table"
@@ -226,6 +230,7 @@ declaration:
 | "%output" "=" string_content             { spec_outfile = $3; }
 | "%parse-param {...}"			   { add_param ("parse_param", $1, @1); }
 | "%pure-parser"                           { pure_parser = true; }
+| "%require" string_content                { version_check (&@2, $2); }
 | "%skeleton" string_content               { skeleton = $2; }
 | "%token-table"                           { token_table_flag = true; }
 | "%verbose"                               { report_flag = report_states; }
@@ -530,6 +535,14 @@ add_param (char const *type, char *decl, location loc)
   scanner_last_string_free ();
 }
 
+static void
+version_check (location const *loc, char const *version)
+{
+  if (strverscmp (version, PACKAGE_VERSION) > 0)
+    complain_at (*loc, "require bison %s, but have %s",
+		 version, PACKAGE_VERSION);
+}
+
 static void
 gram_error (location const *loc, char const *msg)
 {

src/scan-gram.l

@@ -224,6 +224,7 @@ splice	 (\\[ \f\t\v]*\n)*
   "%prec"                 rule_length--; return PERCENT_PREC;
   "%printer"              token_type = PERCENT_PRINTER; BEGIN SC_PRE_CODE;
   "%pure"[-_]"parser"     return PERCENT_PURE_PARSER;
+  "%require"              return PERCENT_REQUIRE;
   "%right"                return PERCENT_RIGHT;
   "%skeleton"             return PERCENT_SKELETON;
   "%start"                return PERCENT_START;