[GSOC] regular expressions beta is here

[Don]

Lutger Blijdestijn wrote:
> Don wrote:
> 
>> bearophile wrote:
>>> Contracts don't replace unittests, they complement each other.
>>>
>>>
>>>> They are nice but have little value over plain assert
>>>> _unless_ we are talking about classes and _inheritance_, which isn't the
>>>> case here.
>>> It's easy to forget to test the output of a function, the "out" contracts
>>> help here. In structs the invariant helps you avoid forgetting to call
>>> manually a sanity test function every time you come in and out of a
>>> method.
>> You're conflating a couple of things here. Invariants are tremendously
>> helpful for structs as well as classes.
>> "out" contracts seem to be almost useless, unless you have a theorem
>> prover. The reason is, that they test nothing apart from the function
>> they are attached to, and it's much better to do that with unittesting.
>> They have very little in common with 'in' contracts.
>>
>> I think that EVERY struct and class in Phobos should have an invariant
>> (except for something like Complex, where there are no invalid values).
>> But I don't think 'out' contracts would add much value at all.
> 
> What about out contracts on interfaces in a library (where you use the 
> library by implementing them).

That involves inheritance. But I don't think there are any cases in 
Phobos where that is currently applicable.