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Date: Sat, 03 Aug 2013 09:35:53 +0200
From: Georg Bauhaus <rm.dash-bauhaus@futureapps.de>
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Subject: Re: Generics vs. O-O?
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Date: 2013-08-03T09:35:51+02:00
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On 03.08.13 02:04, Yannick Duchêne (Hibou57) wrote:
> Le Fri, 02 Aug 2013 10:11:32 +0200, Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> a écrit:
>> Here substitutability encompasses all parameters generics take, not just
>> types. E.g.
>>
>> generic
>>    with function Foo (X : Integer) return Real;
>> package Bar is ...
>>
>> You cannot verify if Baz
>>
>>    function Baz (X : Integer) return Real;
>>
>> were substitutable in Bar for Foo.
>
> I agree with this. Ability to require constraints on type parameters is missing. As an example, I wish I could state it must have some representation set on some value, or require some preconditions and postconditions.
>

Maybe we should coin terms such as "weakly subtyped",
or "weakly constrained" so as to better understand
the foundation of Dmitry's arguments in an Ada context?