Module Name:	pkgsrc
Committed By:	wiz
Date:		Tue May 30 19:25:23 UTC 2006

Modified Files:
	pkgsrc/devel/bison: Makefile PLIST distinfo

Log Message:
Update to 2.2:

* The distribution terms for all Bison-generated parsers now permit
  using the parsers in nonfree programs.  Previously, this permission
  was granted only for Bison-generated LALR(1) parsers in C.

* %name-prefix changes the namespace name in C++ outputs.

* The C++ parsers export their token_type.

* Bison now allows multiple %union declarations, and concatenates
  their contents together.

* New warning: unused values
  Right-hand side symbols whose values are not used are reported,
  if the symbols have destructors.  For instance:

     exp: exp "?" exp ":" exp { $1 ? $1 : $3; }
	| exp "+" exp
	;

  will trigger a warning about $$ and $5 in the first rule, and $3 in
  the second ($1 is copied to $$ by the default rule).  This example
  most likely contains three errors, and could be rewritten as:

     exp: exp "?" exp ":" exp
	    { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
	| exp "+" exp
	    { $$ = $1 ? $1 : $3; if ($1) free ($3); }
	;

  However, if the original actions were really intended, memory leaks
  and all, 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; }
	;

  If there are mid-rule actions, the warning is issued if no action
  uses it.  The following triggers no warning: $1 and $3 are used.

     exp: exp { push ($1); } '+' exp { push ($3); sum (); };

  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 destructors (and the
  experimental printers) as per the documentation.

* Bison now warns if it finds a stray `$' or `@' in an action.

* %require "VERSION"
  This specifies that the grammar file depends on features implemented
  in Bison version VERSION or higher.

* lalr1.cc: The token and value types are now class members.
  The tokens were defined as free form enums and cpp macros.  YYSTYPE
  was defined as a free form union.  They are now class members:
  tokens are enumerations of the `yy::parser::token' struct, and the
  semantic values have the `yy::parser::semantic_type' type.

  If you do not want or can update to this scheme, the directive
  `%define "global_tokens_and_yystype" "1"' triggers the global
  definition of tokens and YYSTYPE.  This change is suitable both
  for previous releases of Bison, and this one.

  If you wish to update, then make sure older version of Bison will
  fail using `%require "2.2"'.

* DJGPP support added.


To generate a diff of this commit:
cvs rdiff -r1.59 -r1.60 pkgsrc/devel/bison/Makefile
cvs rdiff -r1.14 -r1.15 pkgsrc/devel/bison/PLIST
cvs rdiff -r1.17 -r1.18 pkgsrc/devel/bison/distinfo

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.