This accessor combinator lets you access values inside lists.

listRecord = { foo = [ {bar = 2}
                     , {bar = 3}
                     , {bar = 4}
                     ]
             }


get (foo << onEach << bar) listRecord
-- returns [2, 3, 4] 


over (foo << onEach << bar) ((+) 1) listRecord
-- returns {foo = [{bar = 3}, {bar = 4}, {bar = 5}]}

This accessor combinator lets you access values inside Maybe.

maybeRecord = { foo = Just {bar = 2}
              , qux = Nothing
              }


get (foo << try << bar) maybeRecord
-- returns Just 2


get (qux << try << bar) maybeRecord
-- returns Nothing


over (foo << try << bar) ((+) 1) maybeRecord
-- returns {foo = Just {bar = 3}, qux = Nothing}


over (qux << try << bar) ((+) 1) maybeRecord
-- returns {foo = Just {bar = 2}, qux = Nothing}

This accessor combinator lets you access Dict members.

In terms of accessors, think of Dicts as records where each field is a Maybe.

dict = Dict.fromList [("foo", {bar = 2})]


get (dictEntry "foo") dict
-- returns Just {bar = 2}


get (dictEntry "baz" dict)
-- returns Nothing


get (dictEntry "foo" << try << bar) dict
-- returns Just 2


set (dictEntry "foo") Nothing dict
-- returns Dict.remove "foo" dict


set (dictEntry "baz" << try << bar) 3 dict
-- returns dict