regen.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 50fb91efc51d433a15aff9430e871b4a9b29d404..144d865d57774e368941b40bef18877bb6b3146c 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,19 @@ Bison News
 
 Changes in version 1.49b:
 
+* 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
   the use of 2 from the user.  This is no longer the case.
@@ -17,6 +30,18 @@ Changes in version 1.49b:
   user specified that one of her tokens is numbered 256, then error
   will be mapped onto another number.
 
+* 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.
+
 * Large grammars
   Large grammars are now supported (large token numbers, large grammar
   size (= sum of the LHS and RHS lengths), large LALR tables).
@@ -30,6 +55,9 @@ 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.
 
+* Useless rules, useless nonterminals
+  They are now reported, as a warning, with their locations.
+
 * Incorrect `Token not used'
   On a grammar such as
 
@@ -61,7 +89,7 @@ Changes in version 1.49b:
 * Semantic parser
   This old option, which has been broken for ages, is removed.
 
-* New translations
+* New translation
   Croatian, thanks to Denis Lackovic.
 
 * Incorrect token definitions
@@ -72,6 +100,27 @@ 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.
 
+* 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.
 \f
 Changes in version 1.35, 2002-03-25: