DIP 1003 Formal Review

[via Digitalmars-d]

On Saturday, 13 May 2017 at 08:50:10 UTC, Petar Kirov 
[ZombineDev] wrote:
> On Friday, 12 May 2017 at 16:17:03 UTC, Mike Parker wrote:
>> The first stage of the formal review for DIP 1003 [1], "Remove 
>> body as a Keyword", is now underway. From now until 11:59 PM 
>> ET on May 26 (3:59 AM GMT on May 27), the community has the 
>> opportunity to provide last-minute feedback. If you missed the 
>> preliminary review [2], this is your chance to provide input.
>>
>> At the end of the feedback period, I will submit the DIP to 
>> Walter and Andrei for their final decision. Thanks in advance 
>> to those of you who participate.
>>
>> [1] 
>> https://github.com/dlang/DIPs/blob/fbb797f61ac92300eda1d63202157cd2a30ba555/DIPs/DIP1003.md
>>
>> [2] 
>> http://forum.dlang.org/thread/qgxvrbxrvkxtimzvnetu@forum.dlang.org
>
> I vote for option 4 - a combination of 1 and 3:
> * Make body a contextual keyword
> * Allow omitting it
> * No need for deprecation
>
> I don't buy the argument against contextual keywords. D already 
> has them. For example 'C++' can mean two things depending on 
> the context:
>
> // 1:
> int C;
> C++;
>
> // 2:
> extern (C++) void foo();
>
> And also let's not forget that 'in' and 'out' are both 
> parameter storage classes and keywords in the context of 
> contracts.
>
> This has never been a problem for D and other languages are 
> doing great with this feature:
>
> https://docs.microsoft.com/en-us/dotnet/articles/csharp/language-reference/keywords/contextual-keywords
>
> C# also has a way of using identifiers with the same name as 
> reserved keywords:
> https://github.com/dotnet/csharplang/blob/master/spec/lexical-structure.md#identifiers
> (as far as I remember Basile tried to implement this, but ran 
> into some problems, so I'm not sure how doable is such a 
> feature for D, in the presence of mixins).
>
> Even if for this particular case contextual keywords are not 
> the best solution (I disagree), I believe that dismissing them 
> would be mistake. They are a powerful technique in language 
> design that allows evolution of the language without the issues 
> with associated with changing the meaning of / breaking 
> existing user code.

Correction: 'in' and 'out' are not contextual keywords, they are 
an example of giving keywords different meanings in different 
contexts, just like 'static'. AFAIK, you can't use them for 
identifiers, like 'C' - think 'extern (C)'.