Legal fortran?

[lklawrie]

I don't think this is legal Fortran, but IVF didn't complain:

ELSE IF(-25.d0 < CoilInletTemp <=0.0d0) THEN

gfortran did complain.

any comments?

Is this kind of statement legal in c, c++, basic?

(Always trying to figure out where our developers get their syntax).

probably is legal in things like mathlab, Mathematica

Linda

[TimP]

If a compiler accepts this, it's likely done via the extension where logical expressions can be treated as integer. Even then it looks ambiguous. The behavior isn't lkely to resemble what the author intended, no matter what "language" is in use. Yes, it's probably "legal" in C and C++; I hope not in BASIC. ifort should complain if you set -stand.

[Steven_L_Intel1]

This statement is not legal in Fortran. Intel Fortran will accept it, though, via its extension of doing automatic conversion between numeric and logical. It is probably interpreted as:

(23.d0 < CoilInetTemp) <= 0.0D0

where the expression in parentheses yields either a .TRUE. or .FALSE. value. This is then converted to REAL(8) using -1 for .TRUE. and 0 for .FALSE.. If you enable standards checking, it would complain.

This extension has its roots more than three decades ago, but I have been agitating for it to be disabled by default. I will bring this up again.

[TimP]

Quoting Steve Lionel (Intel)

If you enable standards checking, it would complain.

This extension has its roots more than three decades ago, but I have been agitating for it to be disabled by default. I will bring this up again.

I'm in favor. I haven't seen any customers wanting that extension.

[lklawrie]

I agree -- see no reason for allowing that.

I did not see if CVF accepted it. gfortran said "junk". did not check g95 with it either (yet).

in any case, i don't think the compiler is going to do what the developer intended/wants.

Thanks.

Linda

[JVanB]

Obviously it's legal Fortran, and a bug for gfortran to reject it.

[bash]module M
   implicit none
   type T
   end type T
   interface operator(<)
      module procedure op
   end interface operator(<)
   interface operator(<=)
      module procedure op2
   end interface operator(<=)
   contains
      function op(x,y)
         double precision, intent(in) :: x
         type(T), intent(in) :: y
         double precision op

         op = -1
      end function op
      function op2(x,y)
         type(T), intent(in) :: x
         double precision, intent(in) :: y
         double precision op2

         op2 = -1
      end function op2
end module M

program P
   use M
   implicit none
   type(T) CoilInletTemp

   IF(.FALSE.) THEN
   ELSE IF(-25.d0 < CoilInletTemp <=0.0d0) THEN
      write(*,*) 'Test successfully passed.'
   END IF
end program P
[/bash]

[Steven_L_Intel1]

Harumph. Yes, if you define your own operators it can be legal, but I have to assume that wasn't done in Linda's example.