How to create a custom Index that is a function of multiple coordinates/dimensions

I'd like to know if a new feature can be added to have Index knowing about not only its Dimension, but also the other dimensions.

I already shared this with @karllessard , but I'd like to see if we can do something about.
Let me explain: I have a float[rows*columns] table with the actual data and an int[rows*columns] table with permutations to sort each column of the data table separately.

Data table:

data = [ 1.34 0.87 2.45 ]
       [ 0.45 1.56 1.66 ]
       [ 1.02 0.98 0.34 ]

permutations = [ 2 0 2 ]
               [ 0 2 1 ]
               [ 1 1 0 ]

This is a way to have both a sorted and an unsorted version of the data table by using permutations in the indexing when the sorted version is needed.

I was thinking to put the float table in a FloatDataBuffer, then wrap it in a FloatNdArray and create an Index that uses the permutations table. But the fact that we need a separate Index instance for each dimension makes the things complicated (impossible?). Is now the only option to implement my own FloatDataBuffer/FloatNdArray?

Inizia leggendo le astrazioni Index e Dimension, quindi esamina FloatDataBuffer e FloatNdArray per capire come ogni dimensione riceva il proprio Index. Confronta questo design con le tabelle data e permutations descritte. Il lavoro è completo quando viene determinato se un Index condiviso e multidimensionale è realizzabile oppure se è necessario un FloatDataBuffer/FloatNdArray personalizzato; non vengono indicati file o test specifici.