Re: [boost] [optional_io] InputStreamable refinement

Subject: Re: [boost] [optional_io] InputStreamable refinement
From: Ilya Sokolov (ilyasokol_at_[hidden])
Date: 2009-03-03 11:26:38

Fernando Cacciola wrote:
> Or are you saying that, since supporting such a requirement is not 
> entirely possible since in the end is up to T, it isn't worth doing the 
> best optional<T> itself can?

I think so. (We have Boost.Serialization for that)

> I personally never ever needed to extract an optional<T> where a bare T 
> (instead of an optional<T>) was inserted, so the current semantics just 
> worked for me.

How are you using operator>> with optional<T>? I can't imagine any 
common use case other than lexical_cast.

> So, let me step back a bit...
> 
> Why do you (Andrew and you Alexander) need this?
> 
> With the current implementation you can certainly correctly extract the 
> correct output provided the stream was inserted an optional<T>, subject 
> of course to the details of T (as exposed in your counter-example).

Btw, the magic space and '--' string is not documented.

> Why isn't this enough practically speaking rather than theoretically?

The current semantics is useless for me.