Add an a0 edit descriptor analogous to the i0 descriptor

[Beliavsky]

I suggest that an a0 edit descriptor be added that acts like the 'a' descriptor but TRIMs trailing spaces of a string. Because Fortran arrays of strings must have all strings the same size, many strings have redundant trailing spaces. Using the a0 descriptor you could print strings with the minimum size needed, analogous to i0 for integers. Below is an example of the requested feature.

program main
implicit none
integer, parameter :: n = 4
character (len=10) :: c(n)
integer            :: i
c = ["one  ","two  ","three","four "]
write (*,"(1000(a,1x))") (trim(c(i)),i=1,n) ! output: "one two three four"
! desired syntax in line below, to do the same thing as line above:
! write (*,"(1000(a0,1x))") c 
end program main

[certik]

@Beliavsky thanks a lot for submitting the request. I'll ask at the committee what they think.

[gklimowicz]

If you look at the J3 standing document 013 (https://j3-fortran.org/doc/year/19/19-013.pdf), it has the list of things that were under consideration for the next rev of the standard, and the relevant papers where these are elaborated.

This item is listed as "AT (was A0)" for A with TRIM. It's last described in paper 19-137r2 (https://j3-fortran.org/doc/year/19/19-137r2.txt).

My recollection is that the last discussion included whether we should be including trimming blanks on the left as well as the right. That idea was popular with some people. And unpopular with other people.