std.xml validity checking is absurd

[Dmitry Olshansky]

08-Feb-2013 15:25, monarch_dodra пишет:
> On Thursday, 7 February 2013 at 22:36:53 UTC, Andrei Alexandrescu wrote:
>> On 2/7/13 5:27 PM, Vladimir Panteleev wrote:
>>> On Thursday, 7 February 2013 at 22:22:09 UTC, Stewart Gordon wrote:
>>>> This is what I've found: Validity checking is done in an in contract!
>>>
>>> I've ran into the same problem with std.base64. DbC doesn't seem to be a
>>> generally well-understood concept.
>>
>> That's why TDPL dedicates a whole chapter to it (separate from error
>> handling!). Apparently that didn't make a dent in the Universe :o).
>>
>> Andrei
>
> "in" and "out" contracts themselves are flawed in D in any case, given
> they are part of the "called" code, as opposed to "caller" code.
>

+111

> This makes them absolutely no different than an assert.
>
> The problem is that an assert is "internal" validation, whereas an
> "in"/"out" is supposed to be a handshake between the caller/callee.
>
> If I write an "sqrt" function, and document it as "Please, only give me
> positive numbers", and then write a contract for it, and then compile my
> lib in release, the caller will have no way of "signing" my contract.
>
> He'll call my sqrt with negative numbers, and the in will never get
> called, and sqrt will crash horribly.


-- 
Dmitry Olshansky