Re: TR15581 - elemental assignment of structures with alloctable components

[Richard E Maine <Richard dot Maine at nasa dot gov>]

On Jul 5, 2006, at 9:53 AM, Brooks Moses wrote:

> Paul Thomas wrote:
> > The iso_varying_string testsuite now mostly works, except for  
> > vst_2.f95 and three others that have IO problems.  vst_2.f95 fails  
> > on elemental assignment of arrays of structures with allocatable  
> > components....
>
> I think this falls under a category of situations that Richard  
> Maine was talking about on comp.lang.fortran recently --  
> specifically, that the standard expects that allocatable arrays  
> will work exactly as non-allocatable arrays do, except in places  
> where they are explicitly different.  (Specifically, they are not  
> assumed to act like pointers!)...
>
> (i) A copy of the structure is made, and any allocatable components  
> are storage-associated with the corresponding allocatable  
> components of the original, whereas the non-allocatable components  
> are not storage-associated.
> (ii) A copy of the structure is made, and none of the components of  
> the copy are storage-associated with the components of the original.
>
> My opinion is that, when it's looked at that way, the first option  
> is pretty clearly wrong.  Unless one makes assumptions about  
> implementation (which is contrary to the spirit of the Fortran  
> standards), the part about allocatable components being storage- 
> associated on copy just comes out of left field, and makes no sense.

For what it is worth, I agree with Brooks, and I also think that was  
a good job of explanation. I could dig up the citations, but it  
doesn't really seem necessary, as choice 1 is so "obviously" wrong  
that if the standard actually said that I'd be inclined to submit a  
"bug report" (aka interpretation request) on the standard.

--
Richard Maine                |  Good judgment comes from experience;
Richard.Maine@nasa.gov       |  experience comes from bad judgment.
                            |        -- Mark Twain