To: J3                                                     J3/20-124
From: Tom Clune
Subject: Edits for rank-agnostic bounds
Date: 2020-February-27

Reference: 18-007r1, 20-115r1

Introduction:

Paper 20-115r1 provided syntax for rank-agnostic bounds in the form of
BOUNDS and RANK attributes.   This paper provides edits for these features.

Edits:

[xiii Introduction] In paragraph 2, in the bullet for "Data
declaration" , append the following sentence:

"
RANK and BOUNDS attributes have been introduced to support
rank-agnostic declarations.
"

[91:19+ 8.2 Type declaration statement] insert into R802 attr-spec:
"
         <<or>> BOUNDS ( <bounds-attr-spec> )
"	

[91:30+ 8.2 Type declaration statement] insert into R802 attr-spec:
"
         <<or>> RANK ( <scalar-int-constant-expr> )
"	

[91:39+ 8.2 Type declaration statement] insert constraint:

"
C### At most one of BOUNDS, DIMENSION, and RANK shall appear in a
<type-declaration-stmt>.
"

{While consistent duplication is possible, it is at best confusing.}

[95:16- 8.5.5 BIND attribute for data entities] Insert new subclause.

"
8.5.6 BOUNDS attribute

The BOUNDS attribute specifies the rank and bounds of an entity.

<bounds-attr-spec> <<is>> <explicit-shape-bounds-spec>
                   <<or>> <assumed-shape-bounds-spec>

R### <explicit-shape-bounds-spec> <<is>> BOUNDS ( <explicit-shape-bounds> )

R### <explicit-shape-bounds> <<is>> [<explicit-bounds-expr>:]
                                           <explicit-bounds-expr>
                            <<or>> <scalar-int-expr>:<explicit-bounds-expr>
                            <<or>> <explicit-bounds-expr>:<scalar-int-expr>

R### <explicit-bounds-expr> <<is>> is <restricted-expr>

C### If <explicit-shape-bounds> has two <explicit-bounds-expr>s,
     they shall have the same size.

C### <explicit-bounds-expr> shall be a rank one integer array with
     constant size.

R### <assumed-shape-bounds-spec> <<is>> BOUNDS ( <explicit-bounds-expr>: )

C### An entity declared with an <assumed-shape-bounds-spec> shall be a
     dummy data object.


If only one expression appears in <explicit-shape-bounds>, it
specifies the rank and upper bounds of the array.  The rank is the size
of the <explicit-bounds-expr>.

If an expression appears before a colon in <explicit-shape-bounds> it
specifies the lower bounds of the array.  Otherwise, the lower bounds
in each dimension are equal to one.

If <scalar-int-expr> appears in <explicit-shape-bounds>, it is
broadcast to the shape of <explicit-bounds-expr>.

An entity declared with a zero-sized <explicit-bounds-expr> is scalar.


Note ###

Examples of BOUNDS attribute specifications are:
    CHARACTER, BOUNDS([80,24]) :: X3 ! lower bounds are default (=1)
    INTEGER, PARAMETER(*) :: UPPER = [10,10,10]
    INTEGER, BOUNDS (0:UPPER) :: X4 ! implicit broadcast of lower
    REAL, BOUNDS([1,2,3]:10) :: X5 ! implicit broadcast of upper
    INTEGER :: LB(2)
    INTEGER :: UB(2)
    INTEGER, BOUNDS(LB:UB) :: X6A, X6B ! multiple declarations
    REAL, BOUNDS([1,1,1]:) :: X7 ! assumed shape dummy
    INTEGER, BOUNDS([7,7,7]) :: X8A, X9B(10) ! array spec overrides bounds


[105:17- 8.5.15 PROTECTED attribute] Insert new subclause.

"
8.5.16 RANK attribute

The RANK attribute specifies the rank of an entity.  If the rank is
greater than zero and the entity has the ALLOCATABLE or POINTER
attribute, it has deferred shape.  Otherwise, if the rank is greater
than zero, it has assumed shape.

R###  <rank-attr-spec> <<is>>  RANK ( <scalar-int-constant-expr> )

C### The value of <scalar-int-constant-expr> in a <rank-attr-spec>
     shall be nonnegative.

C### An entity declared with a <rank-attr-spec> shall be a dummy data
     object or have the ALLOCATABLE or POINTER attribute.

NOTE ###

Examples of RANK attribute specifications are:
    INTEGER, RANK(3), ALLOCATABLE :: X1
    REAL, RANK(0) :: X2  ! scalar dummy
"