(j3.2006) (SC22WG5.4825) [ukfortran] J3/12-nnn J3 interpretations letter ballot #26 after meeting 198 - due 12-Oct-2012

Malcolm Cohen malcolm
Mon Oct 15 00:23:15 EDT 2012


Robert Corbett writes:
<<<
Rafix Zurob's proposal in meeting 199 was similar to this proposal.  The problem we identified then was that the change made in Fortran 2008 has been integrated into the standard in more than one place.  For example, in Fortran 2003, the statement

      P => Q + 1

where the operation Q + 1 returns a pointer to a data object is permitted.  If only the change suggested is made,
>>>
I think you mean ?the edit suggested?... as my suggested change was to remove the operator syntax for denoting variables that was added in F2008.  In F2003, Q+1 does not denote a variable, in fact quite the opposite, it returns a ?pointer association?.  This is not required to denote a variable!
<<<
that statement will not be permitted in Fortran 2008.
>>>
Right, it would be a mistake to introduce that incompatibility.  I was not suggesting making that mistake.
It looks to me like F2008 has another mistake here already, since Q+1 is permitted to return a null pointer, and this definitively does not denote any variable!
I accept that my initial suggested edits are not complete.  However, there are relatively few places in the language that count as ?pointer context?, so it will not be onerous to check that these will all be ok (but I didn?t do that before making my interp ballot comment).

<<< 
  There are decisions that will have to be made regarding the ASSOCIATE and SELECT TYPE statements.
>>>

There are decisions to be made full stop.  I do not see any particular reason to treat associate selectors that are expressions differently from any other expressions though.
Cheers,
-- 
....................Malcolm Cohen, NAG.
 
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