(j3.2006) late comment

[Van Snyder]

On Tue, 2008-08-26 at 19:57 -0400, Dan Nagle wrote:
> Hello,
> 
> There appears to be one late comment.
> 
> FWIW, I've attached it.
> 
> 
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        For intrinsic procedures that return string values, such as
        ERRMSG, it would be quite useful to allow ERRMSG to refer to an
        unallocated
        allocatable string, which the procedure can automatically
        allocate to the right length. Alternatively, there should be a
        way to query the maximum length to avoid truncation, or a
        mechanism to access ERRMSG strings via an integer error value
        for errors that have already occurred.

I proposed this at the Oxford J3 meeting, immediately before the
Cadarache WG5 meeting in 2000.  The paper didn't get a second, even
though it had been discussed extensively in pre-meeting correspondence.

        Robert Corbett commented on difficulties of type equivalences
        for
        SEQUENCE derived types

        It may not be necessary for the F2008 standard to explicitly
        define the algorithm needed to distinguish sequence derived
        types, ...

A sketch of one is attached.  This is based on the algorithm described
at http://www.cs.adelaide.edu.au/~idea/idea2/fred.htm (a
graph-equivalence algorithm), or the one described in Aho, Sethi, and
Ullman, Compilers: Principles, Techniques and Tools, Addison Wesley,
1988 page 354 Fig 6.6.

        but it would be good to have an example implementation worked
        out to ensure that there is a reasonable approach that still
        fits into the type-matching rules.

Recursively-related sequence derived types have been around since 1990,
so processors already know how to do this.  The problem Corbett had was
with the description.  The new wrinkle is parameters, which aren't
discussed in 4.5.2.4p2 of the current draft.

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