To:      J3                                        J3/14-178r1
From:    David Muxworthy/Malcolm Cohen
Subject: UK proposal UK-16 INTENT(IN) and VALUE
Date: 2014 June 23


Status: For Consideration
Basic Functionality: Remove anomaly of INTENT(IN) and VALUE for
generic interfaces

Rationale:
Constraint C1267 for pure procedures in F03 was "The
specification-part of a pure subroutine subprogram shall specify the
intents of all its nonpointer dummy data objects".  In F08 this was
changed to (C1277) "The specification-part of a pure subroutine
subprogram shall specify the intents of all its nonpointer dummy data
objects that do not have the VALUE attribute" but this change was not
reflected in the description of generic interfaces.  This leads to
anomalies such as:

PURE SUBROUTINE s(a,b)
  TYPE(t),INTENT(Out) :: a
  TYPE(t),VALUE :: b
  ...
END SUBROUTINE

is valid in itself, but

INTERFACE ASSIGNMENT(=)
  MODULE PROCEDURE s
END INTERFACE

is not valid with that procedure.  Similarly for a pure function that
uses VALUE but not INTENT(IN), and OPERATOR(any operator).

A similar situation relates to F03 constraint C1266 which was updated
to C1276 in F08 so as not to require an intent if VALUE was specified,
but C1205 was not updated correspondingly.

Specification:
Update the definition of arguments in generic interfaces and amend
constraint C1205 to align it with C1276 in F08, which is now
C1285 in 14-007r1.

Syntax:
No syntax change.

Edits to J3/14-007r1(= N2014):

[intro] p2, Program units and procedures, append
  "A defined operation need not specify INTENT (IN) for a dummy argument
   with the VALUE attribute.  A defined assignment need not specify INTENT
   (IN) for the second dummy argument if it has the VALUE attribute.".

[281:6] 12.4.3.2 Interface block, before paragraph 1, in C1205,
        "pointer ... procedures arguments"
        ->"for \obs{alternate return indicators,} dummy procedures, and
           arguments with the POINTER or VALUE attribute".

[285:6,7] In 12.4.3.4.2 Defined operations, para 1, lines 5-6,
replace "shall be specified with INTENT (IN)" by "shall have
the INTENT (IN) or VALUE attribute".

[286:3] In 12.4.3.4.3 Defined assignments, para 2, line 3,
replace "INTENT (IN)" by "the INTENT (IN) or VALUE attribute".