Re: Token types with constructor

[Martin Trautmann]

Hi,

I was totally blind. There is already an established solution in the
productive version of bison that allows using Token Classes with
constructor. This works via yyoverflow and a solution of type "3a" may
be implemented as follows:

#define yyoverflow handle_stack_overflow
    namespace adlparser
    {
      short *parserstack_yyss = 0;
      Token *parserstack_yyvs = 0;
  
      void init_stack()
      {
        parserstack_yyss = 0;
        parserstack_yyvs = 0;
      }
      void free_stack()
      {
        if( parserstack_yyss != 0 ) delete[] parserstack_yyss;
        if( parserstack_yyvs != 0 ) delete[] parserstack_yyvs;
        init_stack();
      }
      void handle_stack_overflow( char*, short ** yyss, size_t, Token
**yyvs, size_t, size_t *yystacksize )
      {
        if( parserstack_yyss != 0 ) assert( *yyss == parserstack_yyss );
        if( parserstack_yyvs != 0 ) assert( *yyvs == parserstack_yyvs );
        size_t new_yystacksize = *yystacksize * 2;
        short *new_yyss = new short[new_yystacksize];
        Token *new_yyvs = new Token[new_yystacksize];
        *yyss = new_yyss;
        *yyvs = new_yyvs;
        *yystacksize = new_yystacksize;
        free_stack();
        parserstack_yyss = new_yyss;
        parserstack_yyvs = new_yyvs;
      }
%{
<rules>
%}
void parser_adl()
{
   init_stack();
   yyparse();
   free_stack(); 
}

Like this no memory should be left. The memory originally allocated by
bison on the stack of yyparse is freed automatically calling
destructors.
And as I already described all other copying of Tokens uses the
approriate operator=().

bye

Martin