parser: no longer use the "braceless" non-terminal

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 3816fdd510dae9804d8f79a748582ed19daa3ed4..e06cb77afe83a7b1deb6279082d4b73f791f99dc 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -23,6 +23,26 @@ GNU Bison NEWS
   Missing semicolons at the end of actions are no longer added (as announced
   in the release 2.5).
 
   Missing semicolons at the end of actions are no longer added (as announced
   in the release 2.5).
 

+*** Use of YACC='bison -y'
+
+  TL;DR: With Autoconf <= 2.69, pass -Wno-yacc to (AM_)YFLAGS if you use
+  Bison extensions.
+
+  Traditional Yacc generates 'y.tab.c' whatever the name of the input file.
+  Therefore Makefiles written for Yacc expect 'y.tab.c' (and possibly
+  'y.tab.h' and 'y.outout') to be generated from 'foo.y'.
+
+  To this end, for ages, AC_PROG_YACC, Autoconf's macro to look for an
+  implementation of Yacc, was using Bison as 'bison -y'.  While it does
+  ensure compatible output file names, it also enables warnings for
+  incompatibilities with POSIX Yacc.  In other words, 'bison -y' triggers
+  warnings for Bison extensions.
+
+  Autoconf 2.70+ fixes this incompatibility by using YACC='bison -o y.tab.c'
+  (which also generates 'y.tab.h' and 'y.output' when needed).
+  Alternatively, disable Yacc warnings by passing '-Wno-yacc' to your Yacc
+  flags (YFLAGS, or AM_YFLAGS with Automake).
+

 ** Bug fixes
 
 *** The epilogue is no longer affected by internal #defines (glr.c)
 ** Bug fixes
 
 *** The epilogue is no longer affected by internal #defines (glr.c)


@@ -42,6 +62,8 @@ GNU Bison NEWS
   Changes in Bison 2.7 introduced a dependency on FILE and fprintf when
   locations are enabled.  This is fixed.
 
   Changes in Bison 2.7 introduced a dependency on FILE and fprintf when
   locations are enabled.  This is fixed.
 

+*** Warnings about useless %pure-parser/%define api.pure are restored
+

 ** Diagnostics reported by Bison
 
   Most of these features were contributed by Théophile Ranquet and Victor
 ** Diagnostics reported by Bison
 
   Most of these features were contributed by Théophile Ranquet and Victor


@@ -236,6 +258,23 @@ GNU Bison NEWS
 
     %param {arg1_type *arg1} {arg2_type *arg2}
 
 
     %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
 ** Variable api.token.prefix
 
   The variable api.token.prefix changes the way tokens are identified in


@@ -243,7 +282,7 @@ GNU Bison NEWS
   with identifiers in the target language.  For instance
 
     %token FILE for ERROR
   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;
 
     %%
     start: FILE for ERROR;
 


@@ -274,11 +313,13 @@ GNU Bison NEWS
     yylval.ival = 42; return INT;
     yylval.sval = "42"; return STRING;
 
     yylval.ival = 42; return INT;
     yylval.sval = "42"; return STRING;
 

-  The %define variable api.value.type supports several special values.  The
-  value "union" means that the user provides genuine types, not union member
-  names such as "ival" and "sval" above.
+  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).

 
 

-    %define api.value.type "union"
+    %define api.value.type union

     %token <int> INT "integer"
     %token <char *> STRING "string"
     %printer { fprintf (yyo, "%d", $$); } <int>
     %token <int> INT "integer"
     %token <char *> STRING "string"
     %printer { fprintf (yyo, "%d", $$); } <int>


@@ -288,15 +329,15 @@ GNU Bison NEWS
     yylval.INT = 42; return INT;
     yylval.STRING = "42"; return STRING;
 
     yylval.INT = 42; return INT;
     yylval.STRING = "42"; return STRING;
 

-  The value "variant" is somewhat equivalent, but for C++ special provision
-  is made to allow classes to be used (more about this below).
+  The keyword value variant is somewhat equivalent, but for C++ special
+  provision is made to allow classes to be used (more about this below).

 
 

-    %define api.value.type "variant"
+    %define api.value.type variant

     %token <int> INT "integer"
     %token <std::string> STRING "string"
 
     %token <int> INT "integer"
     %token <std::string> STRING "string"
 

-  Any other name is a user type to use.  This is where YYSTYPE used to be
-  used.
+  Code values (in braces) denote user defined types.  This is where YYSTYPE
+  used to be used.

 
     %code requires
     {
 
     %code requires
     {


@@ -313,7 +354,7 @@ GNU Bison NEWS
         } u;
       };
     }
         } u;
       };
     }

-    %define api.value.type "struct my_value"
+    %define api.value.type {struct my_value}

     %token <u.ival> INT "integer"
     %token <u.sval> STRING "string"
     %printer { fprintf (yyo, "%d", $$); } <u.ival>
     %token <u.ival> INT "integer"
     %token <u.sval> STRING "string"
     %printer { fprintf (yyo, "%d", $$); } <u.ival>


@@ -548,6 +589,21 @@ GNU Bison NEWS
       ...
     }
 
       ...
     }
 

+*** C++ locations
+
+  There are operator- and operator-= for 'location'.  Negative line/column
+  increments can no longer underflow the resulting value.
+
+* Noteworthy changes in release ?.? (????-??-??) [?]
+
+** Bug fixes
+
+*** Fix compiler attribute portability (yacc.c)
+
+  With locations enabled, __attribute__ was used unprotected.
+
+*** Fix some compiler warnings (lalr1.cc)
+

 * Noteworthy changes in release 2.7 (2012-12-12) [stable]
 
 ** Bug fixes
 * Noteworthy changes in release 2.7 (2012-12-12) [stable]
 
 ** Bug fixes