[boost] Re: Fw: Re: Complex type failure with boost::lexical_cast

From: Vladimir Prus (ghost_at_[hidden])
Date: 2005-01-31 01:54:33

Kevlin Henney wrote:

> And that is where the problems begin. The older versions of lexical_cast
> had problems because they behaved like the other types that work with
> I/O streams... but since the other types don't work consistently or
> sensibly with I/O streams, this causes problems. For example, if we do
> as the standard does, then lexical_cast will not work when reading a
> single whitespace character and it will pick out the first
> space-separated sequence from a string. It is unlikely anyone would
> consider this desirable.
> 
> So, if you're going to deal with spaces, deal with them consistently and
> avoid surprises. And over time this is what lexical_cast has been
> converging on. This latest bug is one that will be fixed, continuing the
> trend towards total consumption of the input representation -- we
> thought we had it, but this corner case was missed and fixing it will
> improve coverage. Reverting to inconsistent behaviour is not an
> attractive option.

This still does not answer the real question. If I write something like

   istream& operator>>(istream& is, my_class& c)
   {
 return is >> c.a >> c.b;
   }

then lexical_cast to 'my_class' won't work. Do you think it's the problem
with lexical_cast, or with the above code?

- Volodya