I'd like to set a value in 2 level map - i.e. to a key in a map which is a value for some key in an "outer" map. For ordinary Map I could use something like m & at 42 ?= "value"
But I could not find any way to nest 2 at's
What is the easiest way to set such nested value using lens?
User trapdoor showed up that there is a nicer solution - http://juick.com/qrilka/2602819#19 and it is right in the lens library : non