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

From: bwood (brass_at_[hidden])
Date: 2006-05-15 23:39:44

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David Abrahams wrote:
>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;
>        }

Wait a minute.  The code above looks like you may have focused on 
deleting a member and not relocating it.  "ignored" isn't coming 
from anywhere else with a 1.1 client and it needs to be stored 
somewhere.  Also if a 1.2 server is sending to a 1.1 client, 
it doesn't matter whether the member has been deleted or 
relocated, it still has to send the right thing back.

Brian Wood
www.webEbenezer.net
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