u32regex_replace - None of these prototypes have callback formatter capability

[robic@…]

I've had to do a workaround using a u32regex_iterator.
This one takes parameters wstring, u32regex, and function address.
(Internally it converts the wstring to u32string and does
the replacement with the user callback).

I just have to add more prototypes for the different forms
needed, but it would be nice if I didn't have to do this.

void U_Regex_Replace_Callback( 
	X_string& strSrc,
	U_X_regex& Rx,
	X_32string (*func)(X_u32smatch) )
{
	X_32string str32Src, str32Repl, str32Out;
	WstrToU32string( strSrc, str32Src );
	str32Out.clear();

	boost::u32regex_iterator<std::u32string::const_iterator>
		i(boost::make_u32regex_iterator( str32Src, Rx)), j;
	U32SITR last = str32Src.begin();
	while(i != j)
	{
		str32Out.append( (*i).prefix() );
		str32Out.append( func( (*i) ) ) ;
		last = (*i)[0].second;
	    ++i;
	}
	str32Out.append( last, str32Src.end() );
	U32stringToWstr( str32Out, strSrc );
}