api.token.prefix: use code values

* data/bison.m4: Remove useless (and incorrect: m4_* instead of b4_*)
default assignment to api.token.prefix.
Check that api.token.prefix is assigned code.
* tests/input.at (%define code variables): New test.
* NEWS, doc/bison.texi, tests/c++.at, tests/calc.at,
* tests/java.at, tests/local.at: Adjust to use braces.

9 files changed, 74 insertions, 24 deletions

diff --git a/NEWS b/NEWS
index cf118c15..5bc4d31e 100644
--- a/NEWS
+++ b/NEWS
@@ -256,6 +256,23 @@ GNU Bison NEWS
 
     %param {arg1_type *arg1} {arg2_type *arg2}
 
+** Types of values for %define variables
+
+  Bison used to make no difference between '%define foo bar' and '%define
+  foo "bar"'.  The former is now called a 'keyword value', and the latter a
+  'string value'.  A third kind was added: 'code values', such as '%define
+  foo {bar}'.
+
+  Keyword variables are used for fixed value sets, e.g.,
+
+    %define lr.type lalr
+
+  Code variables are used for value in the target language, e.g.,
+
+    %define api.value.type {struct semantic_type}
+
+  String variables are used remaining cases, e.g. file names.
+
 ** Variable api.token.prefix
 
   The variable api.token.prefix changes the way tokens are identified in
@@ -263,7 +280,7 @@ GNU Bison NEWS
   with identifiers in the target language.  For instance
 
     %token FILE for ERROR
-    %define api.token.prefix "TOK_"
+    %define api.token.prefix {TOK_}
     %%
     start: FILE for ERROR;
 
@@ -294,8 +311,9 @@ GNU Bison NEWS
     yylval.ival = 42; return INT;
     yylval.sval = "42"; return STRING;
 
-  The %define variable api.value.type supports several special values.  The
-  keyword value 'union' means that the user provides genuine types, not
+  The %define variable api.value.type supports both keyword and code values.
+
+  The keyword value 'union' means that the user provides genuine types, not
   union member names such as "ival" and "sval" above (WARNING: will fail if
   -y/--yacc/%yacc is enabled).
 
@@ -316,7 +334,7 @@ GNU Bison NEWS
     %token <int> INT "integer"
     %token <std::string> STRING "string"
 
-  Values between braces denote user defined types.  This is where YYSTYPE
+  Code values (in braces) denote user defined types.  This is where YYSTYPE
   used to be used.
 
     %code requires
diff --git a/data/bison.m4 b/data/bison.m4
index 910cdf26..a5466aa9 100644
--- a/data/bison.m4
+++ b/data/bison.m4
@@ -912,10 +912,6 @@ m4_define([b4_percent_code_ifdef],
 ## Common variables.  ##
 ## ------------------ ##
 
-# Default values for %define.
-# ---------------------------
-# If the api.token.prefix, it is empty.
-m4_percent_define_default([[api.token.prefix]], [[]])
 
 # b4_parse_assert_if([IF-ASSERTIONS-ARE-USED], [IF-NOT])
 # b4_parse_trace_if([IF-DEBUG-TRACES-ARE-ENABLED], [IF-NOT])
@@ -1007,6 +1003,15 @@ b4_percent_define_ifdef([api.prefix],
                 [%name-prefix],
                 [%define api.prefix])])])
 
+# api.token.prefix={...}
+# Make it a warning for those who used betas of Bison 3.0.
+b4_percent_define_ifdef([api.token.prefix],
+  [m4_if(b4_percent_define_get_kind([[api.token.prefix]]), [code], [],
+      [b4_error([deprecated],
+                b4_percent_define_get_loc([api.token.prefix]),
+                [[%%define variable '%s' requires '{...}' values]],
+                [api.token.prefix])])])
+
 # api.value.type >< %union.
 b4_percent_define_ifdef([api.value.type],
 [m4_ifdef([b4_union_members],
diff --git a/doc/bison.texi b/doc/bison.texi
index 72847a1e..58a14f8b 100644
--- a/doc/bison.texi
+++ b/doc/bison.texi
@@ -3787,7 +3787,7 @@ return ID;
 If the @code{%define} variable @code{api.token.prefix} is defined
 (@pxref{%define Summary,,api.token.prefix}), then it is also used to prefix
 the union member names.  For instance, with @samp{%define api.token.prefix
-TOK_}:
+@{TOK_@}}:
 
 @example
 /* For an "integer".  */
@@ -5884,7 +5884,7 @@ introduced in Bison 2.8
 
 
 @c ================================================== api.token.prefix
-@deffn Directive {%define api.token.prefix} @var{prefix}
+@deffn Directive {%define api.token.prefix} @{@var{prefix}@}
 
 @itemize
 @item Languages(s): all
@@ -5895,7 +5895,7 @@ target language.  For instance
 
 @example
 %token FILE for ERROR
-%define api.token.prefix "TOK_"
+%define api.token.prefix @{TOK_@}
 %%
 start: FILE for ERROR;
 @end example
@@ -5922,7 +5922,7 @@ letters, underscores, and ---not at the beginning--- digits).
 @item Default Value:
 empty
 @item History:
-introduced in Bison 2.8
+introduced in Bison 3.0
 @end itemize
 @end deffn
 @c api.token.prefix
@@ -10917,7 +10917,7 @@ also pass the @var{location}.
 For instance, given the following declarations:
 
 @example
-%define api.token.prefix "TOK_"
+%define api.token.prefix @{TOK_@}
 %token <std::string> IDENTIFIER;
 %token <int> INTEGER;
 %token COLON;
@@ -11243,7 +11243,7 @@ tokens with @code{TOK_} (@pxref{%define Summary,,api.token.prefix}).
 
 @comment file: calc++-parser.yy
 @example
-%define api.token.prefix "TOK_"
+%define api.token.prefix @{TOK_@}
 %token
   END  0  "end of file"
   ASSIGN  ":="
diff --git a/src/scan-skel.l b/src/scan-skel.l
index 654491ef..f13ee813 100644
--- a/src/scan-skel.l
+++ b/src/scan-skel.l
@@ -83,7 +83,7 @@ static void fail_for_invalid_at (char const *at);
 "@output("      at_init (&argc, argv, &at_ptr, &at_output);
 
   /* This pattern must not match more than the previous @ patterns. */
-@[^@{}'(\n]*    fail_for_invalid_at (yytext);
+@[^@{}\'(\n]*   fail_for_invalid_at (yytext);
 \n              out_lineno++; ECHO;
 [^@\n]+         ECHO;
 
@@ -183,6 +183,8 @@ flag (const char *arg)
   /* compare with values issued from b4_error */
   if (STREQ (arg, "complain"))
     return complaint;
+  else if (STREQ (arg, "deprecated"))
+    return Wdeprecated;
   else if (STREQ (arg, "fatal"))
     return fatal;
   else if (STREQ (arg, "note"))
diff --git a/tests/c++.at b/tests/c++.at
index 387d4878..d1d6975a 100644
--- a/tests/c++.at
+++ b/tests/c++.at
@@ -325,8 +325,8 @@ AT_TEST([%define parse.assert])
 AT_TEST([%locations %define parse.assert])
 AT_TEST([[%define parse.assert %code {\n#define TWO_STAGE_BUILD\n}]])
 AT_TEST([[%define parse.assert %define api.token.constructor]])
-AT_TEST([[%define parse.assert %define api.token.constructor %define api.token.prefix "TOK_"]])
-AT_TEST([[%locations %define parse.assert %define api.token.constructor %define api.token.prefix "TOK_"]])
+AT_TEST([[%define parse.assert %define api.token.constructor %define api.token.prefix {TOK_}]])
+AT_TEST([[%locations %define parse.assert %define api.token.constructor %define api.token.prefix {TOK_}]])
 
 m4_popdef([AT_TEST])
 
diff --git a/tests/calc.at b/tests/calc.at
index a14f2c21..eedfc897 100644
--- a/tests/calc.at
+++ b/tests/calc.at
@@ -608,7 +608,7 @@ AT_CHECK_CALC_LALR([%define api.push-pull both %define api.pure full %locations]
 AT_CHECK_CALC_LALR([%define parse.error verbose %locations])
 
 AT_CHECK_CALC_LALR([%define parse.error verbose %locations %defines %define api.prefix "calc" %verbose %yacc])
-AT_CHECK_CALC_LALR([%define parse.error verbose %locations %defines %name-prefix "calc" %define api.token.prefix "TOK_" %verbose %yacc])
+AT_CHECK_CALC_LALR([%define parse.error verbose %locations %defines %name-prefix "calc" %define api.token.prefix {TOK_} %verbose %yacc])
 
 AT_CHECK_CALC_LALR([%debug])
 AT_CHECK_CALC_LALR([%define parse.error verbose %debug %locations %defines %name-prefix "calc" %verbose %yacc])
@@ -651,7 +651,7 @@ AT_CHECK_CALC_GLR([%define parse.error verbose %locations %defines %name-prefix
 
 AT_CHECK_CALC_GLR([%debug])
 AT_CHECK_CALC_GLR([%define parse.error verbose %debug %locations %defines %name-prefix "calc" %verbose %yacc])
-AT_CHECK_CALC_GLR([%define parse.error verbose %debug %locations %defines %define api.prefix "calc" %define api.token.prefix "TOK_" %verbose %yacc])
+AT_CHECK_CALC_GLR([%define parse.error verbose %debug %locations %defines %define api.prefix "calc" %define api.token.prefix {TOK_} %verbose %yacc])
 
 AT_CHECK_CALC_GLR([%define api.pure %define parse.error verbose %debug %locations %defines %name-prefix "calc" %verbose %yacc])
 
@@ -684,7 +684,7 @@ AT_CHECK_CALC_LALR1_CC([%locations %define parse.error verbose %define api.prefi
 AT_CHECK_CALC_LALR1_CC([%locations %define parse.error verbose %debug %name-prefix "calc" %verbose %yacc])
 
 AT_CHECK_CALC_LALR1_CC([%locations %pure-parser %define parse.error verbose %debug %define api.prefix "calc" %verbose %yacc])
-AT_CHECK_CALC_LALR1_CC([%locations %pure-parser %define parse.error verbose %debug %define api.prefix "calc" %define api.token.prefix "TOK_" %verbose %yacc])
+AT_CHECK_CALC_LALR1_CC([%locations %pure-parser %define parse.error verbose %debug %define api.prefix "calc" %define api.token.prefix {TOK_} %verbose %yacc])
 
 AT_CHECK_CALC_LALR1_CC([%defines %locations %pure-parser %define parse.error verbose %debug %name-prefix "calc" %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 
@@ -719,7 +719,7 @@ AT_CHECK_CALC_GLR_CC([%debug])
 AT_CHECK_CALC_GLR_CC([%define parse.error verbose %debug %name-prefix "calc" %verbose %yacc])
 
 AT_CHECK_CALC_GLR_CC([%pure-parser %define parse.error verbose %debug %name-prefix "calc" %verbose %yacc])
-AT_CHECK_CALC_GLR_CC([%pure-parser %define parse.error verbose %debug %name-prefix "calc" %define api.token.prefix "TOK_" %verbose %yacc])
+AT_CHECK_CALC_GLR_CC([%pure-parser %define parse.error verbose %debug %name-prefix "calc" %define api.token.prefix {TOK_} %verbose %yacc])
 
 AT_CHECK_CALC_GLR_CC([%locations %defines %pure-parser %define parse.error verbose %debug %name-prefix "calc" %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 AT_CHECK_CALC_GLR_CC([%locations %defines %pure-parser %define parse.error verbose %debug %define api.prefix "calc" %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
diff --git a/tests/input.at b/tests/input.at
index aec855d7..3dfed32d 100644
--- a/tests/input.at
+++ b/tests/input.at
@@ -1435,6 +1435,31 @@ AT_BISON_CHECK([[Input.y]], [1], [],
 AT_CLEANUP
 
 ## ------------------------ ##
+## %define code variables.  ##
+## ------------------------ ##
+
+AT_SETUP([["%define" code variables]])
+
+m4_pushdef([AT_TEST],
+[AT_DATA([input.y],
+[[%define api.token.prefix ]$1[
+%%
+start: %empty;
+]])
+
+AT_BISON_CHECK([[input.y]], [0], [],
+[[input.y:1.9-24: warning: %define variable 'api.token.prefix' requires '{...}' values [-Wdeprecated]
+]])
+])
+
+AT_TEST(["abc"])
+AT_TEST([abcde])
+m4_popdef([AT_TEST])
+
+AT_CLEANUP
+
+
+## ------------------------ ##
 ## %define enum variables.  ##
 ## ------------------------ ##
 
diff --git a/tests/java.at b/tests/java.at
index 7f77f283..3f729260 100644
--- a/tests/java.at
+++ b/tests/java.at
@@ -461,7 +461,7 @@ AT_CHECK_JAVA_GREP([[class YYParser]])
 AT_CHECK_JAVA_MINIMAL([[%name-prefix "Prefix"]])
 AT_CHECK_JAVA_GREP([[class PrefixParser]])
 
-AT_CHECK_JAVA_MINIMAL([[%define api.token.prefix "TOK_"]])
+AT_CHECK_JAVA_MINIMAL([[%define api.token.prefix {TOK_}]])
 AT_CHECK_JAVA_GREP([[.*TOK_END.*]])
 
 AT_CHECK_JAVA_MINIMAL([[%define parser_class_name "ParserClassName"]])
diff --git a/tests/local.at b/tests/local.at
index 46bbfeda..0428b6e8 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -190,8 +190,8 @@ m4_pushdef([AT_NAME_PREFIX],
 m4_pushdef([AT_TOKEN_CTOR_IF],
 [m4_bmatch([$3], [%define api\.token\.constructor], [$1], [$2])])
 m4_pushdef([AT_TOKEN_PREFIX],
-[m4_bmatch([$3], [%define api\.token\.prefix ".*"],
-           [m4_bregexp([$3], [%define api\.token\.prefix "\(.*\)"], [\1])])])
+[m4_bmatch([$3], [%define api\.token\.prefix {.*}],
+           [m4_bregexp([$3], [%define api\.token\.prefix {\(.*\)}], [\1])])])
 m4_pushdef([AT_VARIANT_IF],
 [m4_bmatch([$3], [%define api\.value\.type "?variant"?], [$1], [$2])])
 m4_pushdef([AT_API_prefix],