How can I get a layer ID by its position ? [Script-Fu]

[Nival]

Oh thanks a lot !!
I'm beginner in Script-fu (Scheme) and carefully studied GIMP doc, and in the tutorial about the lists I see no mention of this function !  
They only speak about the use of car / cdr and compounds ... (Which seemed so strange and absurdly complex...)

Quote:3.3.8. Accessing Other Elements In A List

OK, great, we can get the first element in a list, as well as the rest of the list, but how do we access the second, third or other elements of a list? There exist several "convenience" functions to access, for example, the head of the head of the tail of a list (caadr), the tail of the tail of a list (cddr), etc.

The basic naming convention is easy: The a's and d's represent the heads and tails of lists, so

Code:

(car (cdr (car x) ) )

could be written as:

Code:

(cadar x)

To get some practice with list-accessing functions, try typing in the following (except all on one line if you're using the console); use different variations of car and cdr to access the different elements of the list:

     

Code:

 (let* (
                (x  '( (1 2 (3 4 5) 6)  7  8  (9 10) )
                )
             )
             ; place your car/cdr code here
       )

     

Try accessing the number 3 in the list using only two function calls. If you can do that, you're on your way to becoming a Script-Fu Master!

So ... thanks again, all becomes so easy now ! ^^

Note : I really need that the script automatically use other layers ... it's part of the main purpose of my script (purpose of automating tasks, you know )