(j3.2006) Syntax for US-08?

[Van Snyder]

I agree with Bill and Steve that REQUIRE[:] <require-list> is obvious, 
not confusing, and superior to any of the other proposals I've seen.  
I'll write 13-312r1 with a Syntax section that proposes that syntax -- 
unless somebody has a different preference, in which case there will be 
a Syntax section with a proposed straw vote.

Lionel, Steve wrote:
> What customers repeatedly ask us for is "no implicit interface". Personally,
> I don't see the point of tying in the EXTERNAL statement, since as Bill
> suggests it could be confusing and the "external-ness" is not really the
> important attribute (you can have an external procedure with an explicit
> interface.)
>
> I had suggested earlier adding to the IMPLICIT statement syntax something
> like:
>
> IMPLICIT INTERFACE:NONE
>
> but I like the idea of REQUIRE as being more extensible.
>
> Steve
>
> -----Original Message-----
> From: j3-bounces at mailman.j3-fortran.org
> [mailto:j3-bounces at mailman.j3-fortran.org] On Behalf Of Bill Long
> Sent: Thursday, September 26, 2013 1:16 AM
> To: fortran standards email list for J3
> Subject: Re: (j3.2006) Syntax for US-08?
>
> It is a bit unclear to me what is being required here.  If it is just the
> EXTERNAL attribute, then I see the point for functions, but not so much for
> subroutines.  The CALL part of the reference is a pretty unambiguous
> give-away.  On the other hand, if the requirement is for actual interfaces,
> then it would be equally valuable for functions and subroutines.
>
> One possibility would use directly the word in the proposal:
>
> REQUIRE : <xxx-list>
>
> where <xxx> is
>
>     EXTERNAL or
>     INTERFACE or
>     TYPE
>
> The TYPE version would be redundant with IMPLICIT NONE.  INTERFACE would be
> a superset of EXTERNAL, so only one of the two should be specified.
>
> Cheers,
> Bill
>
>
> On 9/25/13 11:39 PM, Malcolm Cohen wrote:
>   
>> 1. I do not feel it is necessary or even particularly desirable to 
>> attempt to "decide" the syntax before the meeting.  Discussion is fine 
>> and good, but decision is out of the question.
>>
>> 2. The "EXTERNAL,ONLY::" suggestion strikes me as being considerably 
>> worse than every alternative.
>>
>> 3. I would have thought Dan was suggesting "EXPLICIT :: EXTERNAL"; 
>> violating the convention that :: introduces a list of names or other 
>> user-defined entities is certainly a minus point.  A single colon 
>> would not fall foul of this convention though.
>>
>> 4. Dan's thought that we might want to make it capable of handling 
>> future conceivable extensions is well taken.  I think that using 
>> parentheses might be better than using colon or double-colon though, e.g.
>> "EXPLICIT(<explicit-item-list>)" or "NO IMPLICIT 
>> (<explicit-item-list>)".  Maybe "NO IMPLICIT(TYPE)" would be short for 
>> "IMPLICIT NONE", and we could have "NO IMPLICIT(LEN)" to get rid of 
>> the implicit character-length==1.  (The latter is out of scope right 
>> now of course.)
>>
>>     
>>>>> The ones I've seen proposed include
>>>>>
>>>>>   IMPLICIT NOEXTERNAL
>>>>>   IMPLICIT, EXTERNAL :: NONE
>>>>>   EXTERNAL, NOIMPLICIT
>>>>>   EXTERNAL, NONE
>>>>>   NO IMPLICIT EXTERNAL
>>>>>   EXTERNAL, EXPLICIT
>>>>>   EXPLICIT[,] EXTERNAL
>>>>>           
>> If you are writing the paper, just put your top three into a straw 
>> vote and list the others in a "rejected syntax" section, preferably with
>>     
> reasons.
>   
>> Cheers,
>>
>>     
>
>   


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