map_l: Promote a lens to apply to each element of a list
Description
Create a new lens that views and sets each element
of the list.
Usage
map_l(l)
Arguments
l
the lens to promote
Details
Uses lapply under the hood for view
and mapply under the hood for set. This means
that set can be given a list of values to set,
one for each element. If the input or update are
lists this lens always returns a list. If the input
and update are vectors this lens will return a vector.