View Source Lens2.Lenses.Keyword (Lens 2 v0.2.1)
Lenses that support duplicate keys in keyword lists.
The lens makers in Lens2.Lenses.Keyed only operate on the first
matching key. These operate on all values, as in the distinction
between Keyword.get/3 and Keyword.get_values/2.
The Deeply.update and Deeply.put functions produce keyword
lists. (Lenses from Lens2.Lenses.Keyed produce maps.)
Summary
Functions
Returns a lens that points to all values of key.
Returns a lens that points to the values of the given keys. Missing keys are to be ignored.
Returns a lens that points to all values of a keyword list.
Functions
@spec key?(atom()) :: Lens2.lens()
Returns a lens that points to all values of key.
iex> kw = [a: 1, b: 2, a: 3]
iex> lens = Lens.Keyword.key?(:a)
iex> Deeply.get_all(kw, lens)
[1, 3]
iex> Deeply.update(kw, lens, & &1 * 1111)
[a: 1111, b: 2, a: 3333]Note that a missing key cannot be added:
iex> Deeply.put([a: 1, b: 2], Lens.Keyword.key?(:missing), :NEW)
[a: 1, b: 2]If you want to add key/value pairs, consider lens makers like
Lens2.Lenses.Indexed.front/0:
iex> Deeply.put([a: 1, b: 2], Lens.front, {:missing, :NEW})
[missing: :NEW, a: 1, b: 2]@spec keys?([atom()]) :: Lens2.lens()
Returns a lens that points to the values of the given keys. Missing keys are to be ignored.
iex> kw = [a: 1, b: 2, a: 3]
iex> lens = Lens.Keyword.keys?([:a, :missing])
iex> Deeply.get_all(kw, lens)
[1, 3]
iex> Deeply.update(kw, lens, & &1 * 1111)
[a: 1111, b: 2, a: 3333]@spec values() :: Lens2.lens()
Returns a lens that points to all values of a keyword list.
iex> kw = [a: 1, b: 2, a: 3]
iex> lens = Lens.Keyword.values
iex> Deeply.get_all(kw, lens)
[1, 2, 3]
iex> Deeply.update(kw, lens, & &1 * 1111)
[a: 1111, b: 2222, a: 3333]