Re: [boost] Re: API Review request: XML APIs for C++

From: Reece Dunn (msclrhd_at_[hidden])
Date: 2003-06-12 06:51:27

Gennadiy Rozental wrote:

>1. No xmlChar type -> template parameter

>namespace xml {
>template<typename Ch, typename Tr>
>class parser {...};
>}

I agree with this, but think that the basic problem is with the underlying 
implementation. The xml++ implementation makes use of libxml2, who's 
underlying representation is xmlChar. I am not sure what this evaluates to, 
but I'll assuming it evaluates to a char. If the library were to be ported 
to another implementation, this may differ (the Microsoft parser uses 
wchar_t).

This means having a conversion manager in the traits class, e.g.

   Traits::representation_type * Traits::convert( Traits::value_type );

The question then is how do you manage possible allocation/deallocation of 
memory, especially when the parameter may be passed through if the two types 
are the same:

   char * traits::convert( char * str ){ return( str ); }

A mechanism needs to be sorted out in order for this to be successful.

>2. No hardcoded virtual functions. In some refinements it still may come to
>use virtual functions here and there. One way to achieve this is to supply
>implementation as template parameter:

I was aiming at a similar idea with my document loader, allowing the XML 
document to be loaded in to the internal representation using a loader 
class. There could then be implementations using libxml2, MSXML3/4, Spirit, 
or another parser.

Regards,
Reece

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