Re: [boost] [type_erasure] Review started (July 18-27, 2012)

Subject: Re: [boost] [type_erasure] Review started (July 18-27, 2012)
From: Paul A. Bristow (pbristow_at_[hidden])
Date: 2012-08-15 12:06:54

> -----Original Message-----
> From: boost-bounces_at_[hidden] [mailto:boost-bounces_at_[hidden]] On Behalf Of Steven
> Watanabe
> Sent: Wednesday, August 08, 2012 3:29 PM
> To: boost_at_[hidden]
> Subject: Re: [boost] [type_erasure] Review started (July 18-27, 2012)
> 
> AMDG

I've wanted to add control of the column width.

    virtual void do_print(
        ostream_type os, iterator_type first, iterator_type last) const {
        if(first != last)
        {
            os << *first;
            ++first;
            for(; first != last; ++first) {
                os << separator.c_str() << *first;
            }
        }

I expected to be able to add

    os.width(20);

before

    os << separator.c_str();

 but that doesn't work.

j:\cpp\misc\type_erasure_lister\./type_erasure_lister.hpp(219): error C2039: 'width' : is not a
member of 'boost::type_erasure::any<Concept,T>'
          with
          [
              Concept=abstract_printer::requirements,
              T=_os &
          ]

Is there some requirement that I need to add to os to permit this?

I stabbed at something like callable<int(int)> but that doesn't help.

Thanks

Paul

---
Paul A. Bristow,
Prizet Farmhouse, Kendal LA8 8AB  UK
[phone]  07714330204
pbristow_at_[hidden]