Re: [boost] [filesystem][program_options][serialization][test]fromcomp.lang.c++.moderated

From: David Abrahams (dave_at_[hidden])
Date: 2006-05-15 08:49:30

bwood <brass_at_[hidden]> writes:

> David Abrahams wrote:
>>>"Le Chaud Lapin" <unoriginal_usern..._at_[hidden]> writes: 
>>>More than anything in programming, I depend on type to create form. 
>>>Versioning implies that types are semi-weak. 
>>
>>
>>If versioning in serialized form implies that, then so do revisions of
>
>>your type in a version control system.  So, basically, once you design
>
>>a class, it never evolves? 
>>
>
> Along the lines of what Lapin is thinking, I think B.Ser's "versioning"
> support is problematic.  For example, consider wanting to move (or 
> delete) a data member out of a type between versions 1.1 and 1.2.
> B.Ser needs that member to remain in the type in order to support 1.1. 

No, you just read it and throw it away.

        if (version == 11)
        {
            type_of_deleted_member ignored;
            ar & ignored;
        }

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com