(j3.2006) badly worded semantics for the IMPORT statement

Bill Long longb
Tue Nov 27 12:21:37 EST 2007


I think this is what was meant: If you have an entity that satisfies two 
conditions:

1) it is available in an interface by being imported, and
2) it is defined in the host scoping unit,

then it is also required to be explicitly declared prior to the 
interface body.   This makes sense in the case of a named constant, 
which is a common thing to be imported.  It does seem to be defective in 
the case of a type name, which is the other common case,  A type is 
defined, but never "declared", so I'd argue that the "declared" is the 
faulty part of the sentence.  A less common case would be to import the 
name of a variable which is not initialized.  It could be used as the 
argument to a KIND() reference as part of a declaration in the 
interface, for example. The current wording does not require that this 
variable be declared before the interface (the sentence does not apply), 
whereas your suggested change would impose this requirement.  It think 
such a change would require an interp.

I'd note that essentially the same statement appears twice, at [260:4-5] 
and [260:11-12], but with different sentence structure.  My wording 
above follows more closely the second sentence in the standard.  Maybe 
it would be clearer, and more consistent, to use the same sentence form 
in both places.

Cheers,
Bill


Robert Corbett wrote:
> Someone here at Sun recently asked why it made a difference whether
> a variable named in an IMPORT statement was assigned a value.  He
> pointed out that Section 12.3.2.1 of the Fortran 2003 standard states
>
>       An entity that is imported in this manner and is defined
>                                                        ^^^^^^^
>       in the host scoping unit shall be explicitly declared
>       prior to the interface body.
>
> Perhaps it would be better to say "declared" instead of "defined."
>
> Bob Corbett
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> J3 at j3-fortran.org
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>   

-- 
Bill Long                                   longb at cray.com
Fortran Technical Support    &              voice: 651-605-9024
Bioinformatics Software Development         fax:   651-605-9142
Cray Inc., 1340 Mendota Heights Rd., Mendota Heights, MN, 55120

            




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