Re: How to correctly deallocate some token types ...

[Ricardo Rafael]

Hi,

Hans Aberg wrote:
> At 00:27 +0100 2003/05/12, Ricardo Rafael wrote:
> >      given the following declarations:
> >
> > %union
> > {
> >   BOOL        boolean_val;
> >   int         integer_val;
> >   char      * string_val;
> >   SomeClass * action;
> >
> >   struct
> >   {
> >     SomeClass * items;
> >     int         length;
> >   } n_list;
> >
> >   struct expression
> >   {
> >     SomeClass * a,
> >               * b,
> >               * c;
> >   } expression;
> > } // YYSTYPE
> ...
> > %destructor { delete $$; } arg_list
> > %destructor { delete $$; } expr

      excuse me by my previous example. It should read as the following:

%destructor { delete $$.items; } arg_list /* is a n_list */
%destructor {
               if ( $$.a ) delete $$.a;
               if ( $$.b ) delete $$.b;
               if ( $$.c ) delete $$.c;
            } expr                        /* is an expression */

> C++ is doing this recursion automatically. But with C++, one
> cannot use %union, as that is implemented using a C/C++ union,
> which does not admit data types with non-trivial constructors.

   That is the case, isn't it!? I just use primitive data types in the 
union (BOOL is a typedef for int just used for compatibility issues of 
one legacy library I use). The non-trivial constructors from class 
SomeClass are dealt indirectly in my code when I call new SomeClass(); 
and the memory deallocation is done using delete (there is no recursive 
data structures pointed by SomeClass *).

   I was just trying to confirm the correctness of the code above.


Thanks,

Ricardo Rafael.