Re: [PATCH] Fix FMT= with CHARACTER arrays (PR fortran/39865, take 2

[dominiq at lps dot ens dot fr (Dominique Dhumieres)]

With your patch (take 2) the following code:

subroutine foo (a)
  integer :: a(:, :)
  write (*, fmt=a) 1, 2, 3, 4, 5, 6, 7, 8
end subroutine foo
  interface
    subroutine foo (a)
      integer :: a(:, :)
    end subroutine foo
  end interface
  integer :: a(5, 5), b(1,2)
  complex :: za(5,10), zb(5,10)
  a = 4HXXXX
  a(2,2) = 4H (8I
  a(2,3) = 2H4)
  b(1,1) = 4H (8I
  b(1,2) = 2H4)
  call foo (b)
  call foo (a(2:2,2:3))
  za = 8HXXXXXXXX
  zb = 8HXXXXXXXX
  za(2,3) = 8H(I1)xxxx
  zb(3,2) = 8H(I10)xxx
  call bar (za, zb)
  write (*, fmt=b(1,1)) 1, 2, 3, 4, 5, 6, 7, 8
contains
   subroutine bar (a,b)
   complex :: a(1:5,1:10)
   complex :: b(:,:)
   write (*, fmt=a(2,3)) 1
   write (*, fmt=b(3,2)) 1
   end subroutine

end

gives

   1   2   3   4   5   6   7   8
   1   2   3   4   5   6   7   8
1
         1
At line 24 of file pr39865_7_db.f90 (unit = 6, file = 'stdout')
Fortran runtime error: Nonnegative width required in format
 (8I
   ^

I think the relevant part of the standard (f95/f03) is:

9.4.1.1 Format specifier
R913 format is default-char-expr
or label
or *
Constraint: The label shall be the label of a FORMAT statement that appears in the same scoping unit
as the statement containing the format specifier.
The default-char-expr shall evaluate to a valid format specification (10.1.1 and 10.1.2).
If default-char-expr is an array, it is treated as if all of the elements of the array were specified in array
element order and were concatenated.

and

10.1.2 Character format specification

If the format specifier references a character array, it is treated as if all of the elements of the array were
specified in array element order and were concatenated. However, if a format specifier references a
character array element, the format specification shall be entirely within that array element.

Note that the above code gives errors with -std=f95 or -std=f2003, not only
for the Hollerith extension, but also for

Error: Extension: Non-character in FORMAT tag at (1)

Dominique