On Monday, October 24, 2016, Angel de Vicente <
angel.vicente.garr...@gmail.com> wrote:
> Hi,
>
> I don't see it in the documentation, but I'm wondering if there is a way
> to have named nested loops, so that one can specify those names to break
> and continue, in order to have more control.
>
> In the following examples, continue always skips the remaining loop for
> j, while break terminates the j loop in the first example and terminates
> the single outer loop in the second (I guess it can be a bit confusing
> at first, but I can understand the design).
>
> ,----
> | println("nested")
> | for i in 1:3
> | for j in 1:6
> | if 2 < j < 4 continue end
> | if j > 5 break end
> | @printf("i: %i j: %i \n",i,j)
> | end
> | end
> |
> | println("single outer loop")
> | for i in 1:3, j in 1:6
> | if 2 < j < 4 continue end
> | if j > 5 break end
> | @printf("i: %i j: %i \n",i,j)
> | end
> `----
>
> But I'm used to Fortran, where one can do things like this (CYCLE ==
> continue ; EXIT == break), and you specify the loop that the instruction
> applies to.
>
> ,----
> | INA: DO a = 1,1000
> | INB: DO b=a+1,1000
> | IF (a+b .GT. 1000) CYCLE INA
> | INC: DO c=b+1,1000
> | IF (a+b+c .GT. 1000) CYCLE INB
> | IF (a+b+c .EQ. 1000 .AND. a**2 + b**2 .EQ. c**2) THEN
> | PRINT*, a*b*c
> | EXIT INA
> | END IF
> | END DO INC
> | END DO INB
> | END DO INA
> `----
>
>
> Is it possible now (or in the near future) to have named nested loops in
> Julia?
No, and I'm not aware of any plan to support this. But you can create
custom control flow with '@goto', so it could be probably be done with a
macro.
>
> Thanks,
> --
> Ángel de Vicente
> http://www.iac.es/galeria/angelv/
>
