09-174r1
To: J3
From: Van Snyder
Subject: Defined operations and assignment
Date: 2009 May 5
References: 09-007r1

1.  Discussion

12.8.2p1 [316:13-14] says "If a generic name or a specific name is
used to reference an elemental function, the shape of the result is the
same as the shape of the actual argument with greatest rank."

There's nothing subsequent in that paragraph about the case of an
elemental function invoked by way of an operator.

We could almost say "The shape of the result of a reference to an
elemental function is the same as the shape of the actual argument with
greatest rank."

The problem is that we don't call the operands of a defined operation
actual arguments.  12.4.3.4.3p2 [287:1-3] does, however, specify that
the left-hand side and the right-hand side of defined assignment are
treated as actual arguments.  It would be better if we specified in both
cases that they ARE actual arguments.

The last sentence of 12.5.2.4p13 [296:29-31] treats operands of defined
operations as if they were actual arguments.

We never get around to saying that defined operations are resolved like
generic names are (we do so for defined assignment at [286:22-24]).

12.4.3.4.3p1 [286:23] says defined assignment is generic if and only if
there is more than one defining subroutine.

The first sentence of 12.8.3p1 [317:2] should apply to both elemental
functions and elemental subroutines.

2.  Edits

[286:10 12.4.3.4.2p1]---------------------------------------------------
Editor: Add a sentence to the paragraph:

"Defined operations are generic in exact analogy to generic procedure
names."

{This allows resolving using 12.5.5.2.}

[286:11-13 12.4.3.4.2p2]------------------------------------------------
Editor: Delete the first sentence.  Replace the second sentence of
12.4.3.4.2p2 ("For a unary ... second dummy argument") by the following:

"A unary defined operation is a reference to the function with its
operand as the actual argument; a binary defined operation is a
reference to the function with its left-hand operand as its first
actual argument and its right-hand operand as its second actual
argument."

[286:22-23 12.4.3.4.3p1]------------------------------------------------
Editor: Delete "may, ... in which case it".

[This makes defined assignment generic even in the case of only one
defining subroutine.

[287:1 12.4.3.4.3p2]----------------------------------------------------
Editor: Delete "treated as".

[287:2-3 12.4.3.4.3p2]--------------------------------------------------
Editor: Insert "actual" before "argument" twice.

[297:7,11 12.5.2.4p18 C1239, C1240]-------------------------------------
Editor: Delete "(R1223)" from both constraints so they apply to defined
operations and defined assignment.

[316:13-14 12.8.2p1]----------------------------------------------------
Editor: Replace the first sentence of 12.8.2p1 ("If a generic ... rank")
by the following:

"The shape of the result of a reference to an elemental function is the
same as the shape of an actual argument with greatest rank."

{Specify the rank of an elemental function referenced by a defined
operation as well as by name.  If there is more than one argument with
the greatest rank "the actual argument with greatest rank" might be
construed not to exist, so use "an actual argument".}

[317:2 12.8.3p1]--------------------------------------------------------
Editor: Replace "An elemental subroutine" by "It".  Then move the
sentence to the end of [316:4 12.8.1p1] so that it applies to all
elemental procedures, not just elemental subroutines.