build: avoid concurrent extraction of calc++.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index b9ce898c183d3b6ec27e103dee2a92509af4446a..aa8c7ea27e903ee44c84807543d51339f3136494 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,33 @@ Bison News
   Also, it is possible to add code to the parser's constructors using
   "%code init" and "%define init_throws".
 
+** Variable api.tokens.prefix
+
+  The variable api.tokens.prefix changes the way tokens are identified in
+  the generated files.  This is especially useful to avoid collisions
+  with identifiers in the target language.  For instance
+
+      %token FILE for ERROR
+      %define api.tokens.prefix "TOK_"
+      %%
+      start: FILE for ERROR;
+
+  will generate the definition of the symbols TOK_FILE, TOK_for, and
+  TOK_ERROR in the generated sources.  In particular, the scanner must
+  use these prefixed token names, although the grammar itself still
+  uses the short names (as in the sample rule given above).
+
+** Variable api.namespace
+
+  The "namespace" variable is renamed "api.namespace".  Backward
+  compatibility is ensured, but upgrading is recommended.
+
+** Variable parse.error
+
+  The variable error controls the verbosity of error messages.  The
+  use of the %error-verbose directive is deprecated in favor of
+  %define parse.error "verbose".
+
 * Changes in version 2.5 (????-??-??):
 
 ** IELR(1) and Canonical LR(1) Support
@@ -41,19 +68,26 @@ Bison News
   These features are experimental.  More user feedback will help to
   stabilize them.
 
+** Multiple %define's for any variable is now an error not a warning.
+
 ** %define can now be invoked via the command line.
 
-  Each of these bison command-line options
+  Each of these command-line options
+
+    -D NAME[=VALUE]
+    --define=NAME[=VALUE]
 
-    -D NAME=VALUE
-    --define=NAME=VALUE
+    -F NAME[=VALUE]
+    --force-define=NAME[=VALUE]
 
   is equivalent to this grammar file declaration
 
-    %define NAME "VALUE"
+    %define NAME ["VALUE"]
 
-  for any NAME and VALUE.  Omitting `=VALUE' on the command line is
-  equivalent to omitting `"VALUE"' in the declaration.
+  except that the manner in which Bison processes multiple definitions
+  for the same NAME differs.  Most importantly, -F and --force-define
+  quietly override %define, but -D and --define do not.  For further
+  details, see the section "Bison Options" in the Bison manual.
 
 ** %define variables renamed.
 
@@ -70,6 +104,14 @@ Bison News
   The old names are now deprecated but will be maintained indefinitely
   for backward compatibility.
 
+** Symbols names
+
+  Consistently with directives (such as %error-verbose) and variables
+  (e.g. push-pull), symbol names may include dashes in any position,
+  similarly to periods and underscores.  This is GNU extension over
+  POSIX Yacc whose use is reported by -Wyacc, and rejected in Yacc
+  mode (--yacc).
+
 ** Temporary hack for adding a semicolon to the user action.
 
   Previously, Bison appended a semicolon to every user action for
@@ -93,6 +135,29 @@ Bison News
 
 * Changes in version 2.4.2 (????-??-??):
 
+** %code is now a permanent feature.
+
+  A traditional Yacc prologue directive is written in the form:
+
+    %{CODE%}
+
+  To provide a more flexible alternative, Bison 2.3b introduced the
+  %code directive with the following forms for C/C++:
+
+    %code          {CODE}
+    %code requires {CODE}
+    %code provides {CODE}
+    %code top      {CODE}
+
+  These forms are now considered permanent features of Bison.  See the
+  %code entries in the section "Bison Declaration Summary" in the Bison
+  manual for a summary of their functionality.  See the section
+  "Prologue Alternatives" for a detailed discussion including the
+  advantages of %code over the traditional Yacc prologue directive.
+
+  Bison's Java feature as a whole including its current usage of %code
+  is still considered experimental.
+
 * Changes in version 2.4.1 (2008-12-11):
 
 ** In the GLR defines file, unexpanded M4 macros in the yylval and yylloc