Re: stl constructs inside the union block

[Hans Aberg]

On 2 Oct 2007, at 23:48, Randy Smith wrote:

> I'm trying to incorporate c++ stl constructs into the %union { }  
> block of yacc.  Specifically, I'm trying to do something similar to  
> this:
>
> %union {
> ...
>    std::list<unsigned int>* int_list;
> ...
> }
>
> This yields the error:
>
> eidd.y:100: error: using-declaration for non-member at class scope
> eidd.y:100: error: expected `;' before '<' token
>
>
> One solution to this (and the solution I used), is to define
> a simple class that wraps a pointer of this type.  This works fine,  
> but
> it is a bit of a kludge, and I'm really curious why the direct stl
> reference doesn't work.  Can anybody explain this to me or point me  
> to a reference?

I think this might be a problem with the C++ compiler or a limitation  
of the C++ standard, because you try to instantiate a pointer to a  
template class, not the class itself. Bison just implements '%union  
{...}' verbatim as 'union {...}'. So perhaps write something before  
that ensures the instantiation of the pointer, experimenting in a  
separate file with what Bison implements.

  Hans Aberg