Type synonym for a type-modifying setter.

Type synonym for a type-preserving setter.

Build a setter from a function to modify the element(s), which must respect the well-formedness laws.

Apply a setter as a modifier.

Create a Setter for a Functor.

over mapped ≡ fmap

Apply a setter.

set o v ≡ over o (const v)

>>> set _1 'x' ('y', 'z')
('x','z')

Apply a setter, strictly.

TODO DOC: what exactly is the strictness property?

Apply a setter as a modifier, strictly.

TODO DOC: what exactly is the strictness property?

Example:

 f :: Int -> (Int, a) -> (Int, a)
 f k acc
   | k > 0     = f (k - 1) $ over' _1 (+1) acc
   | otherwise = acc

runs in constant space, but would result in a space leak if used with over.

Note that replacing $ with $! or _1 with _1' (which amount to the same thing) doesn't help when over is used, because the first coordinate of a pair is never forced.

Rewrite by applying a rule everywhere you can. Ensures that the rule cannot be applied anywhere in the result:

propRewriteOf l r x = all (isNothing . r) (universeOf l (rewriteOf l r x))

Usually transformOf is more appropriate, but rewriteOf can give better compositionality. Given two single transformations f and g, you can construct \a -> f a <|> g a which performs both rewrites until a fixed point.

Since: 0.4.1

Transform every element by recursively applying a given Setter in a bottom-up manner.

Since: 0.4.1

Tag for a setter.