Feature request: Sparse multidimensional array/Enum with tuples

[tobiasBora]

I need to index n-dimensional sparse arrays. So, following suggestions from #846 I tried to do:

enum Men = Man({(5,6), (7,12), (12,4)}); array[Men] of var 0..100: age; constraint age[Man((12, 4))] == 42; solve satisfy; output ["age= \(age)"];

Resulting in the error

MiniZinc: type error: set literals cannot contain tuples

Would it be possible to support this kind of use-cases?

NB: this may relate to #511