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From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2006-04-24 05:04:05

Daniel Walker wrote:
> On 4/23/06, Peter Dimov <pdimov_at_[hidden]> wrote:
>>Daniel Walker wrote:
>>>On 4/23/06, Thorsten Ottosen <thorsten.ottosen_at_[hidden]> wrote:

>>>>Ok, why is that exception better than the one I generate if I don't
>>>>meet the tag I expect, of if the contents of a tag is not of the
>>>>type I expect?
>>>Well, you don't have to write C++ code to check if the tag/content is
>>>what you expect. You declare the acceptable content (tags,
>>>attribute/values, branch structures/sub-trees, etc) for your config
>>>file in a schema, and the parser determines whether or not the XML
>>>file conforms to the format declared in the schema.

>>I wouldn't omit the checks in the code, even when using a validating parser.
>>When the schema and the program logic disagree, the program logic "wins". Or
>>crashes. Either way, the schema loses. :-)
> Good point about crashes. It is still possible to write programs that
> crash even when using a schema. There is no silver bullet. Whether or
> not you want to double check the parser/scheme is the same sort of
> decision as whether or not you define NDEBUG in a released/deployed
> system. Sure, the asserts are still useful, but do you really need the
> extra check? The answer probably depends on the specific circumstances
> and is somewhat a matter of taste. I think the more common case is
> that you forget to manually check a constraint on the XML in your
> code, in which case you would be glad if you had a validating parser.

At least for my code, a crash is not acceptable compared to a nice popup
message: "Error in xml-file: foo";


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