Re: Memory Leaks

[Hans Aberg]

On 18 Nov 2006, at 17:39, Paulo J. Matos wrote:

> > There is now %destructor to clean up C-code leaks during error
> > recovery; otherwise, do it by hand in the actions.
>
> What do you mean by error recovery? If the parsing fails?

Right.

> I still cannot understand when %destructor code is called.

The parser stack is unwound, skipping rule actions, until a recovery  
is deemed possible. So then special cleanup code must be written by  
hand.

> > I think the
> > developers have worked hard to plug the Bison generated parsers. I
> > don't use C, but C++, in which case one can use language features to
> > do the cleanup.
>
> I also use C++ (generating C++ lexer and C parser, I find the C++
> bison interface incomprehensible). What do you mean by language
> features to clean it up?

The C++ parser uses for parser stack a class like std::vector or  
std::deque, which invokes the class destructors when the stack is  
unwound. So if the classes of the objects on the parser stack are  
properly written, no special cleanup is needed.

  Hans Aberg