Re: [Question / Bison 1.875c]: %destructorS not being called at all?

[Jeannot_Langlois]

Tim Van Holder wrote:
> Jeannot_Langlois
> wrote: 
> >  
> > Shouldn't these "%destructor"s be called automatically?  Or am I doing  something
> > wrong (or misunderstanding anything)?  In either case, has  anybody seen
> > this behavior before, and how can I ensure that memory  allocated by "malloc"
> > in semantic actions gets properly freed by  "%destructor"s ? 
> >   
>  
> As I understand it, the %destructors are only called if the parser needs 
> to throw away a token.  If your parser didn't have an error condition, 
> or a parser split in the case of GLR, the parser will probably have 
> successfully passed the tokens to the actions you defined.  As such, it 
> didn't throw any tokens away and didn't call %destructor.  The moment 
> tokens reach action code (even the default action) it becomes your job 
> to clean them up (typically you will place token values in a parse tree 
> of some sort, and you don't want bison to deallocate parts of it behind 
> your back). 
> Also see the 'Destructor Decl' topic in the bison info file. 
>  

Hmmm, okay !  That makes sense too.

I just thought that the tokens would need to be COPIED (that is, reallocated
when inserted) in an AST (and would be freed in my semantic analyzer's address
space later when no longer needed), so bison would need to free them up to
avoid memory leaks.  

Now I realize that I didn't got it the right way.  Then I'll just need to
make sure they are freed when the AST gets destroyed later.


Thanks for your explanations on this,

--
Jeannot Langlois
B. Sc.  Computer Science / B. Sc.  Informatique
Software Developer / Programmeur-Analyste
System/Network Administrator / Administrateur Système/Réseau