* doc/bison.texinfo (Stack Overflow): xref to Recursion.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 50fb91efc51d433a15aff9430e871b4a9b29d404..b8bcae70340c398c9d042a86d8805b0d3019345c 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -1,7 +1,23 @@
 Bison News
 ----------
 
 Bison News
 ----------
 

-Changes in version 1.49b:
+Changes in version 1.49c:
+
+
+Changes in version 1.49b, 2002-08-12:
+
+* GLR parsing
+  The declaration
+     %glr-parser
+  causes Bison to produce a Generalized LR (GLR) parser, capable of handling
+  almost any context-free grammar, ambiguous or not.  The new declarations
+  %dprec and %merge on grammar rules allow parse-time resolution of
+  ambiguities.  Contributed by Paul Hilfinger.
+
+* Output Directory
+  When not in Yacc compatibility mode, when the output file was not
+  specified, runnning `bison foo/bar.y' created `foo/bar.c'.  It
+  now creates `bar.c'.

 
 * Undefined token
   The undefined token was systematically mapped to 2 which prevented
 
 * Undefined token
   The undefined token was systematically mapped to 2 which prevented


@@ -17,9 +33,30 @@ Changes in version 1.49b:
   user specified that one of her tokens is numbered 256, then error
   will be mapped onto another number.
 
   user specified that one of her tokens is numbered 256, then error
   will be mapped onto another number.
 

-* Large grammars
-  Large grammars are now supported (large token numbers, large grammar
-  size (= sum of the LHS and RHS lengths), large LALR tables).
+* Verbose error messages
+  They no longer report `..., expecting error or...' for state where
+  error recovery is possible.
+
+* End token
+  Defaults to `$end' instead of `$'.
+
+* Error recovery now conforms to documentation and to POSIX
+  When a Bison-generated parser encounters a syntax error, it now pops
+  the stack until it finds a state that allows shifting the error
+  token.  Formerly, it popped the stack until it found a state that
+  allowed some non-error action other than a default reduction on the
+  error token.  The new behavior has long been the documented behavior,
+  and has long been required by POSIX.  For more details, please see
+  <http://mail.gnu.org/pipermail/bug-bison/2002-May/001452.html>.
+
+* Traces
+  Popped tokens and nonterminals are now reported.
+
+* Larger grammars
+  Larger grammars are now supported (larger token numbers, larger grammar
+  size (= sum of the LHS and RHS lengths), larger LALR tables).
+  Formerly, many of these numbers ran afoul of 16-bit limits;
+  now these limits are 32 bits on most hosts.

 
 * Explicit initial rule
   Bison used to play hacks with the initial rule, which the user does
 
 * Explicit initial rule
   Bison used to play hacks with the initial rule, which the user does


@@ -30,6 +67,13 @@ Changes in version 1.49b:
   Before, Bison reported the useless rules, but, although not used,
   included them in the parsers.  They are now actually removed.
 
   Before, Bison reported the useless rules, but, although not used,
   included them in the parsers.  They are now actually removed.
 

+* Useless rules, useless nonterminals
+  They are now reported, as a warning, with their locations.
+
+* Rules never reduced
+  Rules that can never be reduced because of conflicts are now
+  reported.
+

 * Incorrect `Token not used'
   On a grammar such as
 
 * Incorrect `Token not used'
   On a grammar such as
 


@@ -52,7 +96,7 @@ Changes in version 1.49b:
 * Token end-of-file
   The token end of file may be specified by the user, in which case,
   the user symbol is used in the reports, the graphs, and the verbose
 * Token end-of-file
   The token end of file may be specified by the user, in which case,
   the user symbol is used in the reports, the graphs, and the verbose

-  error messages instead of `$', which remains being the defaults.
+  error messages instead of `$end', which remains being the default.

   For instance
      %token YYEOF 0
   or
   For instance
      %token YYEOF 0
   or


@@ -62,6 +106,7 @@ Changes in version 1.49b:
   This old option, which has been broken for ages, is removed.
 
 * New translations
   This old option, which has been broken for ages, is removed.
 
 * New translations

+  Brazilian Portuguese, thanks to Alexandre Folle de Menezes.

   Croatian, thanks to Denis Lackovic.
 
 * Incorrect token definitions
   Croatian, thanks to Denis Lackovic.
 
 * Incorrect token definitions


@@ -72,6 +117,29 @@ Changes in version 1.49b:
   the compiler supports ANSI C or is a C++ compiler, as enums.
   This helps debuggers producing symbols instead of values.
 
   the compiler supports ANSI C or is a C++ compiler, as enums.
   This helps debuggers producing symbols instead of values.
 

+* Reports
+  In addition to --verbose, bison supports --report=THINGS, which
+  produces additional information:
+  - itemset
+    complete the core item sets with their closure
+  - lookahead
+    explicitly associate lookaheads to items
+  - solved
+    describe shift/reduce conflicts solving.
+    Bison used to systematically output this information on top of
+    the report.  Solved conflicts are now attached to their states.
+
+* Type clashes
+  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';
+
+  This is fixed.
+
+* GNU M4 is now required when using Bison.

 \f
 Changes in version 1.35, 2002-03-25:
 
 \f
 Changes in version 1.35, 2002-03-25: