In XML output, remove redundant class attribute on symbol element.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 0e4061aab57d2f191120d123592f063f89a338eb..3526e7b46c0b22cf53e7c90b7f15ad806f1cfbde 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -3,17 +3,30 @@ Bison News
 
 Changes in version 2.3a+ (????-??-??):
 
 
 Changes in version 2.3a+ (????-??-??):
 

-* Previously, Bison sometimes generated parser tables with states that were
-  unreachable due to conflicts in predecessor states.  Bison now:
+* The quotes around NAME that used to be required in the following directive
+  are now deprecated:

 
 

-    1. Removes unreachable states.
+    %define NAME "VALUE"

 
 

-    2. Does not report any conflicts that appeared in unreachable states.
-       WARNING: As a result, you may need to update %expect and %expect-rr
-       directives in existing grammar files.
+* The directive `%pure-parser' is now deprecated in favor of:

 
 

-    3. For any rule used only in such states, Bison now reports the rule as
-       "never reduced because of conflicts".
+    %define api.pure
+
+  which has the same effect except that Bison is more careful to warn about
+  unreasonable usage in the latter case.
+
+* Push Parsing
+
+  Bison can now generate an LALR(1) parser in C with a push interface.  That
+  is, instead of invoking `yyparse', which pulls tokens from `yylex', you can
+  push one token at a time to the parser using `yypush_parse', which will
+  return to the caller after processing each token.  By default, the push
+  interface is disabled.  Either of the following directives will enable it:
+
+    %define api.push_pull "push" // Just push; does not require yylex.
+    %define api.push_pull "both" // Push and pull; requires yylex.
+
+  See the new section `A Push Parser' in the Bison manual for details.

 
 * The -g and --graph options now output graphs in Graphviz DOT format,
   not VCG format.
 
 * The -g and --graph options now output graphs in Graphviz DOT format,
   not VCG format.


@@ -28,6 +41,46 @@ Changes in version 2.3a+ (????-??-??):
 
     %defines "parser.h"
 
 
     %defines "parser.h"
 

+* When reporting useless rules, useless nonterminals, and unused terminals,
+  Bison now employs the terms "useless in grammar" instead of "useless",
+  "useless in parser" instead of "never reduced", and "unused in grammar"
+  instead of "unused".
+
+* Unreachable State Removal
+
+  Previously, Bison sometimes generated parser tables containing unreachable
+  states.  A state can become unreachable during conflict resolution if Bison
+  disables a shift action leading to it from a predecessor state.  Bison now:
+
+    1. Removes unreachable states.
+
+    2. Does not report any conflicts that appeared in unreachable states.
+       WARNING: As a result, you may need to update %expect and %expect-rr
+       directives in existing grammar files.
+
+    3. For any rule used only in such states, Bison now reports the rule as
+       "useless in parser due to conflicts".
+
+  This feature can be disabled with the following directive:
+
+    %define lr.keep_unreachable_states
+
+  See the %define entry in the `Bison Declaration Summary' in the Bison manual
+  for further discussion.
+
+* Lookahead Set Correction in the `.output' Report
+  
+  When instructed to generate a `.output' file including lookahead sets
+  (using `--report=lookahead', for example), Bison now prints each reduction's
+  lookahead set only next to the associated state's one item that (1) is
+  associated with the same rule as the reduction and (2) has its dot at the end
+  of its RHS.  Previously, Bison also erroneously printed the lookahead set
+  next to all of the state's other items associated with the same rule.  This
+  bug affected only the `.output' file and not the generated parser source
+  code.
+
+* --report-file=FILE is a new flag to override the default `.output' file name.
+

 * The `=' that used to be required in the following directives is now
   deprecated:
 
 * The `=' that used to be required in the following directives is now
   deprecated:
 


@@ -35,12 +88,9 @@ Changes in version 2.3a+ (????-??-??):
     %name-prefix "c_"
     %output "parser.c"
 
     %name-prefix "c_"
     %output "parser.c"
 

-* The quotes around NAME that used to be required in the following directive
-  are now deprecated:
-
-    %define NAME "VALUE"
+* An Alternative to `%{...%}' -- `%code QUALIFIER {CODE}'

 
 

-* Bison 2.3a provided a new set of directives as a more flexible alternative to
+  Bison 2.3a provided a new set of directives as a more flexible alternative to

   the traditional Yacc prologue blocks.  Those have now been consolidated into
   a single %code directive with an optional qualifier field, which identifies
   the purpose of the code and thus the location(s) where Bison should generate
   the traditional Yacc prologue blocks.  Those have now been consolidated into
   a single %code directive with an optional qualifier field, which identifies
   the purpose of the code and thus the location(s) where Bison should generate


@@ -79,7 +129,9 @@ Changes in version 2.3a+ (????-??-??):
   To enable these warnings, specify the flag `--warnings=midrule-values' or
   `-W', which is a synonym for `--warnings=all'.
 
   To enable these warnings, specify the flag `--warnings=midrule-values' or
   `-W', which is a synonym for `--warnings=all'.
 

-* Bison now recognizes two separate kinds of default %destructor's and
+* Default %destructor or %printer with `<*>' or `<>'
+
+  Bison now recognizes two separate kinds of default %destructor's and

   %printer's:
 
     1. Place `<*>' in a %destructor/%printer symbol list to define a default
   %printer's:
 
     1. Place `<*>' in a %destructor/%printer symbol list to define a default