Deprecate %pure-parser and add `%define api.pure'. Discussed starting

at
<http://lists.gnu.org/archive/html/bison-patches/2007-09/msg00006.html>.
* NEWS (2.3a+): Mention.
* data/bison.m4 (b4_pure_if): Don't define it here.
* data/c.m4 (b4_identification): Depend on individual skeletons to
define b4_pure_flag, b4_push_flag, or b4_pull_flag if they use the
values of the %define variables api.pure or api.push_pull.  Define
YYPURE, YYPUSH, and YYPULL accordingly.
* data/glr.c: Define b4_pure_if based on `%define api.pure' unless
glr.cc has already defined b4_pure_flag.
* data/push.c: Define b4_pure_if based on `%define api.pure'.
Remove YYPUSH and YYPULL since they're back in b4_identification again.
* data/yacc.c Define b4_pure_if based on `%define api.pure'.
* doc/bison.texinfo (Pure Decl): Update.
(Push Decl): Update.
(Decl Summary): Add api.pure to %define entry.
In %pure-parser entry, say it's deprecated and reference %define.
(Pure Calling): Update.
(Error Reporting): Update.
(C++ Scanner Interface): Update.
(How Can I Reset the Parser): Update.
(Table of Symbols): In %pure-parser entry, say it's deprecated and
reference %define.
* src/getargs.c (pure_parser): Remove global variable.
* src/getargs.h (pure_parser): Remove extern.
* src/output.c (prepare): Don't define pure_flag muscle.
* src/parse-gram.y (prologue_declaration): Implement %pure-parser as a
wrapper around `%define api.pure'.
* tests/calc.at (Simple LALR Calculator): Update.
(Simple GLR Calculator): Update.
* tests/cxx-type.at (GLR: Resolve ambiguity, pure, no locations):
Update.
(GLR: Resolve ambiguity, pure, locations): Update.
(GLR: Merge conflicting parses, pure, no locations): Update.
(GLR: Merge conflicting parses, pure, locations): Update.
* tests/glr-regression.at (Uninitialized location when reporting
ambiguity): Update
* tests/input.at (Unused %define api.pure): New test case.
* tests/local.at (_AT_BISON_OPTION_PUSHDEFS): Update definition for
AT_PURE_IF and AT_PURE_AND_LOC_IF.
* tests/push.at (Push Parsing: Memory Leak for Early Deletion): Update.

src/getargs.c

@@ -59,7 +59,6 @@ bool error_verbose = false;
 
 bool nondeterministic_parser = false;
 bool glr_parser = false;
-bool pure_parser = false;
 
 int report_flag = report_none;
 int trace_flag = trace_none;

src/getargs.h

@@ -51,11 +51,6 @@ extern bool error_verbose;
 
 extern bool glr_parser;
 
-/* PURE_PARSER is true if should generate a parser that is all pure
-   and reentrant.  */
-
-extern bool pure_parser;
-
 /* NONDETERMINISTIC_PARSER is true iff conflicts are accepted.  This
    is used by the GLR parser, and might be used in BackTracking
    parsers too.  */

src/output.c

@@ -571,7 +571,6 @@ prepare (void)
   MUSCLE_INSERT_BOOL ("glr_flag", glr_parser);
   MUSCLE_INSERT_BOOL ("locations_flag", locations_flag);
   MUSCLE_INSERT_BOOL ("nondeterministic_flag", nondeterministic_parser);
-  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 ("use_push_for_pull_flag", use_push_for_pull_flag);

src/parse-gram.h

@@ -160,7 +160,7 @@
 typedef union YYSTYPE
 {
 
-/* Line 1538 of yacc.c  */
+/* Line 1542 of yacc.c  */
 #line 94 "parse-gram.y"
 
   symbol *symbol;
@@ -174,7 +174,7 @@ typedef union YYSTYPE
 
 
 
-/* Line 1538 of yacc.c  */
+/* Line 1542 of yacc.c  */
 #line 179 "parse-gram.h"
 } YYSTYPE;
 # define YYSTYPE_IS_TRIVIAL 1

src/parse-gram.y

@@ -266,7 +266,19 @@ prologue_declaration:
 | "%output" STRING              { spec_outfile = $2; }
 | "%output" "=" STRING          { spec_outfile = $3; }  /* deprecated */
 | "%parse-param" "{...}"	{ add_param ("parse_param", $2, @2); }
-| "%pure-parser"                { pure_parser = true; }
+| "%pure-parser"
+    {
+      /* %pure-parser is deprecated in favor of `%define api.pure', so use
+         `%define api.pure' in a backward-compatible manner here.  First, don't
+         complain if %pure-parser is specified multiple times.  */
+      if (!muscle_find_const ("percent_define(api.pure)"))
+        muscle_percent_define_insert ("api.pure", @1, "");
+      /* In all cases, use api.pure now so that the backend doesn't complain if
+         the skeleton ignores api.pure, but do warn now if there's a previous
+         conflicting definition from an actual %define.  */
+      if (!muscle_percent_define_flag_if ("api.pure"))
+        muscle_percent_define_insert ("api.pure", @1, "");
+    }
 | "%require" STRING             { version_check (&@2, $2); }
 | "%skeleton" STRING
     {