Provide different accessors in the Access module #4009
Description
The goal is to provide accessors to be used alongside Kernel.put_in and friends. For example:
put_in sample[:foo][:bar], :bazCan be thought as a shortcut to:
put_in sample, [Access.key(:foo), Access.key(:bar)], :bazWhere Access.key(:foo) will return a function as described by Kernel.get_and_update_in. Similar would exist for structs:
put_in sample.foo.bar, :bazis equivalent to:
put_in sample, [Access.field(:foo), Access.field(:bar)], :bazFor now, we will also provide all/0 and at/1 for lists and elem/1 for tuples. The question is the naming convention for those functions. For example, we could prefix most of them by by_: by_key, by_elem and by_field, although it wouldn't work for all/0 and at/1. Alternatively, we can drop the by_ prefix, although it could be confusing if mixed with the existing fetch/2, get/3 and friends.
Thoughts?