For those kind of reports, I would look into the 'VirtualList'-technic and ExecuteSQL() to gather the data. Just do a search for 'FileMaker VirtualList' or have a look at this example: Outer Joins in FileMaker 12, part 3 | FileMakerHacks
FIleMaker does have looping structure in scripting:
Set Variable [$i ; 0]
Set Variable [$total ; 10]
Exit Loop If [$total ≥ $i]
If you need looping in calculations you can use recursive custom functions recursion.
As a substitute for arrays you can use repeated fields (a bit old fashioned), variables with repetition (e.g. $i) , lists or temporarily tables.
Exactly what I need...!!!