Re: glr & locations

[Claudia Hermann]

Paul Hilfinger wrote:
> > On Fri, 28 Oct 2005, Claudia Hermann wrote:
>
>
> > > i have a parser with glr activated and use the location tracking
> > > function.  every things works fine as long as i don't use
> > > ambiguous rules where i have to choose between with '%dprec'.
> > > additionally i have an optional nonterminal at the beginning of
> > > the rule. in this special case i get undefined values for the
> > > optional nonterminal as well as for the whole rule. 
>
> ...
>
> > It's a bug in bison still in the latest CVS sources.
> >
> > YYLLOC_DEFAULT is supposed to copy the location for an empty non-terminal 
> > from the location of the previous symbol, but the current implementation 
> > loses that location during a split GLR parse.
>
>
>
> The following patch works for me, and passes make check. However, I
> haven't really had time to properly test it.

this patch works fine as long as i do not call yyparse() twice and only 
use the default YYLTYPE declaration. but once i redeclare YYLTYPE and 
YYLLOC_DEFAULT and activate glr-parser, as first value of the first node 
i get the last value of the last node of the previous parsed file.
see also attached file

regards,
claudia hermann

%{

  #if ! defined (YYLTYPE)
  typedef struct yyltype {
    long int first_pos;
    long int last_pos;
  } yyltype;
  #define YYLTYPE yyltype
  #endif

  #ifndef YYLLOC_DEFAULT
  #define YYLLOC_DEFAULT(Current, Rhs, N)                           \
    do                                                              \
      if (N) {                                                      \
        (Current).first_pos   = YYRHSLOC (Rhs, 1).first_pos;        \
        (Current).last_pos    = YYRHSLOC (Rhs, N).last_pos;         \
      }                                                             \
      else {                                                        \
        (Current).first_pos   = (Current).last_pos   =              \
          YYRHSLOC (Rhs, 0).last_pos;                               \
      }                                                             \
    while (0)
  #endif


  static void yyerror(const char *msg);
  int i = 0;
%}


%token T_PORT
%token T_SIGNAL

%glr-parser

%%


DesignUnit      : ContextClause LibraryUnit
                { printf("%d/%d, %d/%d\n", @1.first_pos, @1.last_pos, 
@2.first_pos, @2.last_pos); }
        ;

LibraryUnit     : T_PORT
        ;


ContextClause   : /* empty */
        | ContextClause ContextItem
        ;

ContextItem     : T_SIGNAL
        ;

%%

static void yyerror(const char *msg) {
  printf ("error\n");
}

int yylex() {
  if (i == 0) {
    yylloc.first_pos = 0;
    yylloc.last_pos = 8;
    i++;
    return T_SIGNAL;
  }

  if (i == 1) {
    yylloc.first_pos = 10;
    yylloc.last_pos = 14;
    i++;
    return T_PORT;
  }


  return 0;
}


int main (int argc, const char *argv[]) {
  yyparse();
  i = 0;
  yyparse();
  return 0;
}