J3/01-159r1
							page 1 of 2
Date:    21 March 2001
To:      J3
From:    John Reid/Rich Bleikamp
Subject: Interpretation 25 (List-directed input: types of variables
         corresponding to repeated values)

Here is a draft answer for interp. 25. This was discussed at Oulu
without reaching a resolution. WG5 commented as follows (WG5/N1410)

   Section 10.8 [175:7-9] states: "The r*c form is equivalent to r
   successive appearances of the constant c, and the r* form is
   equivalent to r successive appearances of the null value."

   WG5/interp  was unable to agree on whether r*c implied r copies of
   the characters in c or r copies of the constant implied by c,
   possibly after the association of the first copy in the input record
   with its associated list item.  Both interpretations are possible
   from the text.  The answer to the question is accordingly no or
   yes.

I have prepared a draft answer based on the first alternative, because
I believe that this is what was intended and it is what most compilers
do.
- - End of John's comments - -
- - Rich's comments - -
JOR believes the 2nd alternative above is correct, and can be deduced
from a careful reading of section 10.8.

..................................................

NUMBER: 000025
TITLE: List-directed input: types of variables corresponding to repeated values
KEYWORDS:
DEFECT TYPE: Erratum
STATUS: J3 consideration in progress

QUESTION:

When a repeat count is used in list-directed input, must all the variables into
which the repeated value is read have the same type?  I see no reason in the
standard to assume that restriction, but at least one Fortran 90 implementation
assumes it.



                                                        J3/01-159r1
							page 2 of 2
ANSWER:

No, the variables are not required to be of the same type, but the type
of the repeated constant is either a literal constant, or a nondelimited
character constant, but not both (10.8, "where <c> is a literal constant
or a nondelimited character constant").  Whether certain forms of a repeated
constant are treated as a literal constant or a nondelimited character
constant is determined by the type of the first variable which consumes
this value.  Indeed, how many characters from the input record are part
of <c> is dependent on the type of the first variable which consumes a
value from that <r*c>.


For example, the input
   2*(1.0, 0.0)
conforms to the standard when consumed by three list items of type character
or by two list items of type complex.  If there are three character
variables, the first two get the value "(1.0", while the third gets the
value "0.0)".  If there are two complex variables, they both are assigned
the value (1.0,0.0).

Similarly, the input
   2*.TRUE.
can be consumed by two logical variables, or two character variables,
but not by one character and one logical variable.

An edit is provided to clarify the situation.

EDIT:

In section 10.8.1,  add the following as a new paragraph, just before
Note 10.26 [175:33+].
  "For the <r*c> form of an input value, the constant <c> is interpreted
  as a nondelimited character constant if the first list item
  corresponding to this value is of type default character, there is
  a nonblank character immediately after <r*>, and that character is not an
  apostrophe or a quotation mark; otherwise, <c> is interpreted as a
  literal constant."

SUBMITTED BY: Robert Corbett
HISTORY:  98-155   m145 Submitted (part 3)
          WG5/N1410     Draft answer