Re: [boost] [serialization]A question about the implementation of XML_name in basic_xml_oarchive.ipp

From: Simon Buchan (simon_at_[hidden])
Date: 2005-09-28 20:35:42

Caleb Epstein wrote:
> On 9/28/05, David Abrahams <dave_at_[hidden]> wrote:
> 
> 
>>Hmm... Also, is the apparent dependency on ASCII encoding truly portable?
> 
> 
> 
> Doubtful. Wouldn't testing for std::isalnum || '-' || '_' be a better idea?
> Perhaps not quite as performant (once the lookup table was made static), but
> certainly more portable and simpler to read.
> 
> --
> Caleb Epstein
> caleb dot epstein at gmail dot com
> _______________________________________________
> Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
> 
In most implementations, the is*()'s are implemented using exactly the 
same method.  It's generally safe, as pretty much every code-page 
barring EBCDIC (or whatever it is) that isn't obviously non-latin (CJK 
codepages, espcially) uses the ASCII characters for values less than 
128, including the Unicode code-points (8 is particularly good at this: 
all the surrogates are > 127).  If it is a CJK code-page, you're screwed 
no matter what you do. (wide characters, and just what is an 
"alphabetic" ideograph?)