+* Wording in the Bison-generated parsers has been changed slightly to
+ simplify translation. In particular, the message "memory exhausted"
+ has replaced "parser stack overflow", as the old message was not
+ always accurate for modern Bison-generated parsers.
+
+* Destructors are now called when the parser aborts, for all symbols left
+ behind on the stack. Also, the start symbol is now destroyed after a
+ successful parse. In both cases, the behavior was formerly inconsistent.
+
+* When generating verbose diagnostics, Bison-generated parsers no longer
+ quote the literal strings associated with tokens. For example, for
+ a syntax error associated with '%token NUM "number"' they might
+ print 'syntax error, unexpected number' instead of 'syntax error,
+ unexpected "number"'.
+
+Changes in version 2.0, 2004-12-25:
+
+* Possibly-incompatible changes
+
+ - Bison-generated parsers no longer default to using the alloca function
+ (when available) to extend the parser stack, due to widespread
+ problems in unchecked stack-overflow detection. You can "#define
+ YYSTACK_USE_ALLOCA 1" to require the use of alloca, but please read
+ the manual to determine safe values for YYMAXDEPTH in that case.
+
+ - Error token location.
+ During error recovery, the location of the syntax error is updated
+ to cover the whole sequence covered by the error token: it includes
+ the shifted symbols thrown away during the first part of the error
+ recovery, and the lookahead rejected during the second part.
+
+ - Semicolon changes:
+ . Stray semicolons are no longer allowed at the start of a grammar.
+ . Semicolons are now required after in-grammar declarations.
+
+ - Unescaped newlines are no longer allowed in character constants or
+ string literals. They were never portable, and GCC 3.4.0 has
+ dropped support for them. Better diagnostics are now generated if
+ forget a closing quote.
+
+ - NUL bytes are no longer allowed in Bison string literals, unfortunately.
+
+* New features
+
+ - GLR grammars now support locations.
+
+ - New directive: %initial-action.
+ This directive allows the user to run arbitrary code (including
+ initializing @$) from yyparse before parsing starts.
+
+ - A new directive "%expect-rr N" specifies the expected number of
+ reduce/reduce conflicts in GLR parsers.
+
+ - %token numbers can now be hexadecimal integers, e.g., `%token FOO 0x12d'.
+ This is a GNU extension.
+
+ - The option `--report=lookahead' was changed to `--report=look-ahead'.
+ The old spelling still works, but is not documented and will be
+ removed.
+
+ - Experimental %destructor support has been added to lalr1.cc.
+
+ - New configure option --disable-yacc, to disable installation of the
+ yacc command and -ly library introduced in 1.875 for POSIX conformance.
+
+* Bug fixes
+
+ - For now, %expect-count violations are now just warnings, not errors.
+ This is for compatibility with Bison 1.75 and earlier (when there are
+ reduce/reduce conflicts) and with Bison 1.30 and earlier (when there
+ are too many or too few shift/reduce conflicts). However, in future
+ versions of Bison we plan to improve the %expect machinery so that
+ these violations will become errors again.
+
+ - Within Bison itself, numbers (e.g., goto numbers) are no longer
+ arbitrarily limited to 16-bit counts.
+
+ - Semicolons are now allowed before "|" in grammar rules, as POSIX requires.
projects / bison.git / blobdiff