over {lenses}

Map a function over a lens

Description

Get the data pointed to by a lens, apply a function and replace it with the result.

Usage

over(d, l, f)

Arguments

d

the data (or an oscope)

l

the lens (or the function if d is an oscope)

f

the function (or nothing if d is an oscope)

Examples

third_l <- index(3)
over(1:5, third_l, function(x) x + 2)
# returns c(1:2, 5, 4:5)