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.
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
about a missing semicolon where it did not before. Future releases of
Bison will cease to append semicolons entirely.
+** Character literals not of length one.
+
+ Previously, Bison quietly converted all character literals to length
+ one. For example, without warning, Bison interpreted the operators in
+ the following grammar to be the same token:
+
+ exp: exp '++'
+ | exp '+' exp
+ ;
+
+ Bison now warns when a character literal is not of length one. In
+ some future release, Bison will report an error instead.
+
* Changes in version 2.4.2 (????-??-??):
** %code is now a permanent feature.