+* New warning: unused values
+ Typed right-hand side symbols whose value are not used are reported.
+ For instance:
+
+ exp: exp "?" exp ":" exp { $$ = $1 ? $1 : $3; }
+ | exp "+" exp
+ ;
+
+ will trigger a warning about $5 of the first rule, and $3 in the
+ second ($1 is copied to $$ by the default rule). This example
+ most likely contains two errors, and should be rewritten as:
+
+ exp: exp "?" exp ":" exp { $$ = $1 ? $3 : $5; }
+ | exp "+" exp { $$ = $1 + $3; }
+ ;
+
+ However, if the original actions were really intended, the warnings
+ can be suppressed by letting Bison believe the values are used, e.g.:
+
+ exp: exp "?" exp ":" exp { $$ = $1 ? $1 : $3; (void) $5; }
+ | exp "+" exp { $$ = $1; (void) $3; }
+ ;
+
+ The warning is intended to help catching lost values and memory leaks.
+ If a value is ignored, its associated memory typically is not reclaimed.
+
+* %destructor vs. YYABORT, YYACCEPT, and YYERROR.
+ Destructors are now called when user code invokes YYABORT, YYACCEPT,
+ and YYERROR, for all objects on the stack, other than objects
+ corresponding to the right-hand side of the current rule.
+
+* %expect, %expect-rr
+ Incorrect numbers of expected conflicts are now actual errors,
+ instead of warnings.
+
+* GLR, YACC parsers.
+ The %parse-params are available in the %destructor's (and the
+ experimental %printer's) as per the documentation.
+
+* Bison now warns if it finds a stray `$' or `@' in an action.
+
+* %require "VERSION"
+ To specify that the grammar file depends on features implemented in
+ Bison version VERSION or higher.
+
projects / bison.git / blobdiff