[J3] [EXTERNAL] Re: 21-120r2: Discussion on the feasibility of any future enhancement of Enumeration Type

[Bill Long]

> On Mar 2, 2021, at 3:40 PM, Reuben D. Budiardja via J3 <j3 at mailman.j3-fortran.org> wrote:
> 
> On 03/02/2021 01:11 PM, Ondřej Čertík via J3 wrote:
>> Hi,
>> The paper https://j3-fortran.org/doc/year/21/21-110r1.txt is extending the enum type, here is an example syntax (from the paper):
>> Module enum_mod
>>   Enum,Bind(C) :: myenum
>>     Enumerator :: one=1, two, three
>>   End Enum
>>   Enum,Bind(C) :: flags
>>     Enumerator :: f1 = 1, f2 = 2, f3 = 4
>>   End Enum
>> Contains
>>   Subroutine sub(a) Bind(C)
>>     Type(myenum),Value :: a
>>     Print *,a ! Acts as if it is Print *,Int(a).
>>   End Subroutine
>> End Module
>> Why cannot we simply allow to drop the `bind(c)`, then we have an enumeration type that we can use?
> 
> Because this does not satisfy the requirements for "true enumerations types". The purpose of this one is to be better interoperable with C enum.

Additionally, I don’t see why the BIND(C) is harmful.  You can put BIND(C) on lots of things that never end up interacting with C.  It just enforces certain storage requirements. 

Cheers,
Bill


> 
> 
>> I do not think we should have two enumeration types in the language.
> 
> The way I see it, there will only be one enumeration type in 202X. This is 21-120r2. 21.110 is / should be really part of the interoperability with C.
> 
> Best,
> Reuben
> 
> 

Bill Long                                                                       longb at hpe.com
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