Data.Array.Lens

Setters

ixmapped :: (IArray a e, Ix i, Ix j) => (i, i) -> IndexPreservingSetter (a j e) (a i e) i j

This setter can be used to derive a new IArray from an old IAarray by applying a function to each of the indices to look it up in the old IArray.

This is a contravariant Setter.

 ixmap ≡ over . ixmapped
 ixmapped ≡ setting . ixmap
 over (ixmapped b) f arr ! i ≡ arr ! f i
 bounds (over (ixmapped b) f arr) ≡ b