tests: use the generalized default yylex.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 14f51b3e3263093ef079e83b71812f6f2132e831..33fac14571f23f3bb5d93d826a204319f0c91fec 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -1,7 +1,76 @@
-Bison News
-----------
+GNU Bison NEWS

 
 

-* Changes in version 2.5.1_rc2 (2012-05-23):
+* Noteworthy changes in release ?.? (????-??-??) [?]
+
+** Future changes
+
+  The next major release of Bison will drop support for the following
+  deprecated features.  Please report disagreements to bug-bison@gnu.org.
+
+*** K&C parsers
+
+  Support for generating parsers in K&R C will be removed.  Parsers
+  generated for C supprt ISO C90, and are tested with ISO C99 and ISO C11
+  compilers.
+
+*** Features deprecated since Bison 1.875
+
+  The definitions of yystype and yyltype will be removed; use YYSTYPE and
+  YYLTYPE.
+
+  YYPARSE_PARAM and YYLEX_PARAM, deprecated in favor of %parse-param and
+  %lex-param, will no longer be supported.
+
+  Support for the preprocessor symbol YYERROR_VERBOSE will be removed, use
+  %error-verbose.
+
+*** The generated header will be included (yacc.c)
+
+  Instead of duplicating the content of the generated header (definition of
+  YYSTYPE, yyparse declaration etc.), the generated parser will include it,
+  as is already the case for GLR or C++ parsers.  This change is deferred
+  because existing versions of ylwrap (e.g., Automake 1.12.1) do not support
+  it.
+
+** Headers
+
+*** Guards (yacc.c, glr.c, glr.cc)
+
+  The generated headers are now guarded, as is already the case for C++
+  parsers (lalr1.cc).  For intance, with --defines=foo.h:
+
+    #ifndef YY_FOO_H
+    # define YY_FOO_H
+    ...
+    #endif /* !YY_FOO_H  */
+
+*** New declarations (yacc.c, glr.c)
+
+  The generated header now declares yydebug and yyparse.  Both honor
+  --name-prefix=bar_, and yield
+
+    int bar_parse (void);
+
+  rather than
+
+    #define yyparse bar_parse
+    int yyparse (void);
+
+  in order to facilitate the inclusion of several parser headers inside a
+  single compilation unit.
+
+*** Exported symbols in C++
+
+  The symbols YYTOKEN_TABLE and YYERROR_VERBOSE, which were defined in the
+  header, are removed, as they prevent the possibility of including several
+  generated headers from a single compilation unit.
+
+*** YYLSP_NEEDED
+
+  For the same reasons, the undocumented and unused macro YYLSP_NEEDED is no
+  longer defined.
+
+* Noteworthy changes in release 2.5.1 (2012-06-05) [stable]

 
 ** Future changes:
 
 
 ** Future changes:
 


@@ -38,10 +107,10 @@ Bison News
   The header files such as "parser.hh", "location.hh", etc. used a constant
   name for preprocessor guards, for instance:
 
   The header files such as "parser.hh", "location.hh", etc. used a constant
   name for preprocessor guards, for instance:
 

-  #ifndef BISON_LOCATION_HH
-  # define BISON_LOCATION_HH
-  ...
-  #endif // !BISON_LOCATION_HH
+    #ifndef BISON_LOCATION_HH
+    # define BISON_LOCATION_HH
+    ...
+    #endif // !BISON_LOCATION_HH

 
   The inclusion guard is now computed from "PREFIX/FILE-NAME", where lower
   case characters are converted to upper case, and series of
 
   The inclusion guard is now computed from "PREFIX/FILE-NAME", where lower
   case characters are converted to upper case, and series of


@@ -49,10 +118,10 @@ Bison News
 
   With "bison -o lang++/parser.cc", "location.hh" would now include:
 
 
   With "bison -o lang++/parser.cc", "location.hh" would now include:
 

-  #ifndef YY_LANG_LOCATION_HH
-  # define YY_LANG_LOCATION_HH
-  ...
-  #endif // !YY_LANG_LOCATION_HH
+    #ifndef YY_LANG_LOCATION_HH
+    # define YY_LANG_LOCATION_HH
+    ...
+    #endif // !YY_LANG_LOCATION_HH

 
 *** C++ locations:
 
 
 *** C++ locations:
 


@@ -93,7 +162,7 @@ Bison News
   This includes warnings with some compilers, unexpected behavior of tools
   such as diff, warning messages from the test suite itself, etc.
 
   This includes warnings with some compilers, unexpected behavior of tools
   such as diff, warning messages from the test suite itself, etc.
 

-*** The install-pdf target work properly:
+*** The install-pdf target works properly:

 
   Running "make install-pdf" (or -dvi, -html, -info, and -ps) no longer
   halts in the middle of its course.
 
   Running "make install-pdf" (or -dvi, -html, -info, and -ps) no longer
   halts in the middle of its course.


@@ -283,33 +352,33 @@ Bison News
   to use it.  If, for instance, your location structure has "first"
   and "last" members, instead of
 
   to use it.  If, for instance, your location structure has "first"
   and "last" members, instead of
 

-      # define YYLLOC_DEFAULT(Current, Rhs, N)                             \
-        do                                                                 \
-          if (N)                                                           \
-            {                                                              \
-              (Current).first = (Rhs)[1].location.first;                   \
-              (Current).last  = (Rhs)[N].location.last;                    \
-            }                                                              \
-          else                                                             \
-            {                                                              \
-              (Current).first = (Current).last = (Rhs)[0].location.last;   \
-            }                                                              \
-        while (false)
+    # define YYLLOC_DEFAULT(Current, Rhs, N)                             \
+      do                                                                 \
+        if (N)                                                           \
+          {                                                              \
+            (Current).first = (Rhs)[1].location.first;                   \
+            (Current).last  = (Rhs)[N].location.last;                    \
+          }                                                              \
+        else                                                             \
+          {                                                              \
+            (Current).first = (Current).last = (Rhs)[0].location.last;   \
+          }                                                              \
+      while (false)

 
   use:
 
 
   use:
 

-      # define YYLLOC_DEFAULT(Current, Rhs, N)                             \
-        do                                                                 \
-          if (N)                                                           \
-            {                                                              \
-              (Current).first = YYRHSLOC (Rhs, 1).first;                   \
-              (Current).last  = YYRHSLOC (Rhs, N).last;                    \
-            }                                                              \
-          else                                                             \
-            {                                                              \
-              (Current).first = (Current).last = YYRHSLOC (Rhs, 0).last;   \
-            }                                                              \
-        while (false)
+    # define YYLLOC_DEFAULT(Current, Rhs, N)                             \
+      do                                                                 \
+        if (N)                                                           \
+          {                                                              \
+            (Current).first = YYRHSLOC (Rhs, 1).first;                   \
+            (Current).last  = YYRHSLOC (Rhs, N).last;                    \
+          }                                                              \
+        else                                                             \
+          {                                                              \
+            (Current).first = (Current).last = YYRHSLOC (Rhs, 0).last;   \
+          }                                                              \
+      while (false)

 
 ** YYLLOC_DEFAULT in C++:
 
 
 ** YYLLOC_DEFAULT in C++:
 


@@ -928,26 +997,26 @@ Bison News
   if the symbols have destructors.  For instance:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; }
   if the symbols have destructors.  For instance:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; }

-       | exp "+" exp
-       ;
+        | exp "+" exp
+        ;

 
   will trigger a warning about $$ and $5 in the first rule, and $3 in
   the second ($1 is copied to $$ by the default rule).  This example
   most likely contains three errors, and could be rewritten as:
 
      exp: exp "?" exp ":" exp
 
   will trigger a warning about $$ and $5 in the first rule, and $3 in
   the second ($1 is copied to $$ by the default rule).  This example
   most likely contains three errors, and could be rewritten as:
 
      exp: exp "?" exp ":" exp

-           { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
-       | exp "+" exp
-           { $$ = $1 ? $1 : $3; if ($1) free ($3); }
-       ;
+            { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
+        | exp "+" exp
+            { $$ = $1 ? $1 : $3; if ($1) free ($3); }
+        ;

 
   However, if the original actions were really intended, memory leaks
   and all, the warnings can be suppressed by letting Bison believe the
   values are used, e.g.:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; (void) ($$, $5); }
 
   However, if the original actions were really intended, memory leaks
   and all, the warnings can be suppressed by letting Bison believe the
   values are used, e.g.:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; (void) ($$, $5); }

-       | exp "+" exp         { $$ = $1; (void) $3; }
-       ;
+        | exp "+" exp         { $$ = $1; (void) $3; }
+        ;

 
   If there are mid-rule actions, the warning is issued if no action
   uses it.  The following triggers no warning: $1 and $3 are used.
 
   If there are mid-rule actions, the warning is issued if no action
   uses it.  The following triggers no warning: $1 and $3 are used.


@@ -1162,6 +1231,33 @@ Bison News
   - "parsing stack overflow..." -> "parser stack overflow"
     GLR parsers now report "parser stack overflow" as per the Bison manual.
 
   - "parsing stack overflow..." -> "parser stack overflow"
     GLR parsers now report "parser stack overflow" as per the Bison manual.
 

+** %parse-param and %lex-param
+  The macros YYPARSE_PARAM and YYLEX_PARAM provide a means to pass
+  additional context to yyparse and yylex.  They suffer from several
+  shortcomings:
+
+  - a single argument only can be added,
+  - their types are weak (void *),
+  - this context is not passed to anciliary functions such as yyerror,
+  - only yacc.c parsers support them.
+
+  The new %parse-param/%lex-param directives provide a more precise control.
+  For instance:
+
+    %parse-param {int *nastiness}
+    %lex-param   {int *nastiness}
+    %parse-param {int *randomness}
+
+  results in the following signatures:
+
+    int yylex   (int *nastiness);
+    int yyparse (int *nastiness, int *randomness);
+
+  or, if both %pure-parser and %locations are used:
+
+    int yylex   (YYSTYPE *lvalp, YYLTYPE *llocp, int *nastiness);
+    int yyparse (int *nastiness, int *randomness);
+

 ** Bison now warns if it detects conflicting outputs to the same file,
   e.g., it generates a warning for "bison -d -o foo.h foo.y" since
   that command outputs both code and header to foo.h.
 ** Bison now warns if it detects conflicting outputs to the same file,
   e.g., it generates a warning for "bison -d -o foo.h foo.y" since
   that command outputs both code and header to foo.h.


@@ -1191,16 +1287,16 @@ Bison News
   In agreement with POSIX and with other Yaccs, leaving a default
   action is valid when $$ is untyped, and $1 typed:
 
   In agreement with POSIX and with other Yaccs, leaving a default
   action is valid when $$ is untyped, and $1 typed:
 

-       untyped: ... typed;
+        untyped: ... typed;

 
   but the converse remains an error:
 
 
   but the converse remains an error:
 

-       typed: ... untyped;
+        typed: ... untyped;

 
 ** Values of mid-rule actions
   The following code:
 
 
 ** Values of mid-rule actions
   The following code:
 

-       foo: { ... } { $$ = $1; } ...
+        foo: { ... } { $$ = $1; } ...

 
   was incorrectly rejected: $1 is defined in the second mid-rule
   action, and is equal to the $$ of the first mid-rule action.
 
   was incorrectly rejected: $1 is defined in the second mid-rule
   action, and is equal to the $$ of the first mid-rule action.


@@ -1282,9 +1378,9 @@ Bison News
 ** Incorrect "Token not used"
   On a grammar such as
 
 ** Incorrect "Token not used"
   On a grammar such as
 

-           %token useless useful
-           %%
-           exp: '0' %prec useful;
+    %token useless useful
+    %%
+    exp: '0' %prec useful;

 
   where a token was used to set the precedence of the last rule,
   bison reported both "useful" and "useless" as useless tokens.
 
   where a token was used to set the precedence of the last rule,
   bison reported both "useful" and "useless" as useless tokens.


@@ -1303,9 +1399,9 @@ Bison News
   the user symbol is used in the reports, the graphs, and the verbose
   error messages instead of "$end", which remains being the default.
   For instance
   the user symbol is used in the reports, the graphs, and the verbose
   error messages instead of "$end", which remains being the default.
   For instance

-     %token MYEOF 0
+    %token MYEOF 0

   or
   or

-     %token MYEOF 0 "end of file"
+    %token MYEOF 0 "end of file"

 
 ** Semantic parser
   This old option, which has been broken for ages, is removed.
 
 ** Semantic parser
   This old option, which has been broken for ages, is removed.


@@ -1341,9 +1437,9 @@ Bison News
   Previous versions don't complain when there is a type clash on
   the default action if the rule has a mid-rule action, such as in:
 
   Previous versions don't complain when there is a type clash on
   the default action if the rule has a mid-rule action, such as in:
 

-      %type <foo> bar
-      %%
-      bar: '0' {} '0';
+    %type <foo> bar
+    %%
+    bar: '0' {} '0';

 
   This is fixed.
 
 
   This is fixed.