Re: Shortcut logicals (was: Re: F200x )

["James Van Buskirk" <not_valid@comcast.net>]

"James Giles" <jamesgiles@worldnet.att.net> wrote in message
news:ZaCLd.474$xR1.216@bgtnsc04-news.ops.worldnet.att.net...

>    x/=0.0 .and. cond2 .andthen. cond3 .and. 5.0/x>10.0

> ?=>

>    5.0/x>10.0 .and. x/=0.0 .and. cond2 .andthen. cond3

>    cond2 .andthen. cond3 .and. 5.0/x>10.0 .and. x/=0.0

Obviously the first short-circuits the DIVCHK and the last two
don't.

> One of the reasons it took me a while to respond is that I *did*
> read what you wrote (and couldn't find the subtle relevance you
> assert) - I've just reread it again.  My puzzlement still remains.
> It does seem to me that the case where all operands are scalar
> ought to be simpler than more exotic possibilities.  And a simple
> IF (or even a scalar logical assignment statement) ought to be
> simpler to discuss that a WHERE construct.

Obviously you don't get it.  How do you know what array gets
passed to sub:

module mymod
   implicit none
   contains
      subroutine sub(x)
         logical, intent(in) :: x(:)

         write(*,*) size(x)
      end subroutine sub

      function f(n)
         integer, intent(in) :: n
         logical f(n)
         integer i

         f = mod(mod((17+(/(i,i=1,n)/))**2,97),2) == 0
      end function f
end module mymod

program test
   use mymod
   implicit none
   integer n
   real x

   write(*,'(a)',advance='no') 'Enter the size of the array:> '
   read(*,*) n
   write(*,'(a)',advance='no') 'Enter a number:> '
   read(*,*) x

   call sub(x/=0 .AND_THEN. n > 0 .AND. f(n))
end program test

So pick apart the first typo you find and tell me you still
don't get it... [sigh].

-- 
write(*,*) transfer((/17.392111325966148d0,6.5794487871554595D-85, &
6.0134700243160014d-154/),(/'x'/)); end