J3/13-207

To: J3
From: Van Snyder
Subject: Inquiry functions for designators such as a%b%c%...%z
Date: 2013 December 19

Title: Inquiry functions for designators such as a%b%c%...%z

Submitted by: Van Snyder

Status: For consideration

Basic functionality: Allow an inquiry function with an argument that is
a designator of the form a%b%c%...%z, even if more than one part-ref is
an array, or some part-refs are disassociated pointers or deallocated
allocatables.

Rationale: One cannot inquire properties of a component if a part-ref
that precedes it in a data-ref is a disassociated pointer or deallocated
allocatable, or if more than one part-ref is an array.  There are no
simple work-arounds for this use in specification expressions.

Estimated impact: Minor

Markham M6 conformance: Remove simple deficiency, inconsistency and
discrepancy.

Detailed specification: Allow an inquiry function with an argument that
is a designator of the form a%b%c%...%z, even if more than one part-ref
is an array, or part-refs preceding the last one are disassociated
pointers or deallocated allocatables.  The only allowed inquiries are
those that depend only upon the type and kind of the final part-ref:

BIT_SIZE, DIGITS, EPSILON, HUGE, KIND, NULL, PRECISION, RADIX, RANGE, or
TINY, or the inquiry functions in the intrinsic module IEEE_ARITHMETIC,

Draft edits: To estimate scope of project

Replace C618 with

C618 (R611) Except as an actual argument to the intrinsic functions
            BIT_SIZE, DIGITS, EPSILON, HUGE, KIND, NULL, PRECISION,
            RADIX, RANGE, or TINY, or the inquiry functions in the
            intrinsic module IEEE_ARITHMETIC, there shall not be more
            than one <part-ref> with nonzero rank, and a <part-ref> to
            the right of a <part-ref> with nonzero rank shall not have
            the ALLOCATABLE or POINTER attribute.

Insert a sentence in 13.1p2:

"In the argument to any of the intrinsic functions BIT_SIZE, DIGITS,
EPSILON, HUGE, KIND, NULL, PRECISION, RADIX, RANGE, or TINY, or the
inquiry functions in the intrinsic module IEEE_ARITHMETIC, a component
at any level of component selection may be a pointer that is not
associated with a target, or an allocatable component that is not
allocated."