From: Vladimir Prus (ghost_at_[hidden])
Date: 2004-03-12 08:11:33
Reece Dunn wrote:
> > 2) The output operator puts spaces after '[', before ']',
> > and after each ','; whereas the input operator expects
> > no spaces at all; if spaces were present, a bad_lexical_cast
> > exception was thrown. I think it is really important that
> > operator>> can deal with an output which was generated by <<;
> > stated in terms of lexical_cast,
> > lexical_cast<T>( lexical_cast<string>( t ) ) == t
> > should hold for any T t.
> I stripped and skipped the spaces during the read operation to allow for
> the read operation to accommodate input variations, e.g. [ a, b ]; [a, b]
> and [ a,b ] would be read by the same formatter, making it easier to
> interoperate with data generated from other sources. I could make this a
> configurable option that does not strip the spaces by default.
It's really good question if the >> operator should be prepared to find a
stream which has 'skipws' bit unset. Given that streams usually generate
human-readable data, skipping whitespace is a common behaviour, and I'd say
that 'noskipws' manipulator should be used only for special circumstances.
So, in my opinion lexical_cast<T> should not use 'noskipws', and not force
other libraries to manually skip whitespace.
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk