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José Valim
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Deprecate Dict.Behaviour in favor of Dict
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‎CHANGELOG.md‎

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@@ -15,7 +15,7 @@
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* [OptionParser] `--` is always removed from argument list on `parse/2` and when it is the leading entry on `parse_head/2`
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* Soft deprecations (no warnings emitted)
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* [Dict] `Dict.Behaviour` is deprecated (please define the Dict functions yourself)
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* [Dict] `Dict.Behaviour` is deprecated in favor of `Dict`
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* [Kernel] `Application.Behaviour`, `GenEvent.Behaviour`, `GenServer.Behaviour` and `Supervisor.Behaviour` are deprecated in favor of `Application`, `GenEvent`, `GenServer` and `Supervisor`
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* [Kernel] `defexception/3` is deprecated in favor of `defexception/1`
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* [Kernel] `raise/3` is deprecated in favor of `reraise/2`

‎lib/elixir/lib/dict.ex‎

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@@ -31,6 +31,70 @@ defmodule Dict do
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Dictionaries are required to implement all operations
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using the match (`===`) operator.
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## Default implementation
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Default implementations for some functions in the `Dict` module
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are provided via `use Dict`.
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For example:
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defmodule MyDict do
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use Dict.Behaviour
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# implement required functions (see below)
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# override default implementations if optimization
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# is needed
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end
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The client module must contain the following functions:
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* `delete/2`
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* `fetch/2`
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* `put/3`
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* `reduce/3`
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* `size/1`
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All functions, except `reduce/3`, are required by the Dict behaviour.
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`reduce/3` must be implemtented as per the Enumerable protocol.
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Based on these functions, `Dict` generates default implementations
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for the following functions:
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* `drop/2`
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* `equal?/2`
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* `fetch!/2`
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* `get/2`
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* `get/3`
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* `has_key?/2`
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* `keys/1`
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* `merge/2`
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* `merge/3`
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* `pop/2`
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* `pop/3`
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* `put_new/3`
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* `split/2`
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* `take/2`
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* `to_list/1`
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* `update/4`
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* `update!/3`
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* `values/1`
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All of these functions are defined as overridable, so you can provide
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your own implementation if needed.
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Note you can also test your custom module via `Dict`'s doctests:
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defmodule MyDict do
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# ...
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end
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defmodule MyTests do
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use ExUnit.Case
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doctest Dict
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defp dict_impl, do: MyDict
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end
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"""
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use Behaviour
@@ -63,6 +127,146 @@ defmodule Dict do
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defcallback update!(t, key, (value -> value)) :: t | no_return
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defcallback values(t) :: list(value)
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defmacro __using__(_) do
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# Use this import to guarantee proper code expansion
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import Kernel, except: [size: 1]
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quote do
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@behaviour Dict
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def get(dict, key, default \\ nil) do
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case fetch(dict, key) do
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{:ok, value} -> value
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:error -> default
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end
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end
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def fetch!(dict, key) do
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case fetch(dict, key) do
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{:ok, value} -> value
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:error -> raise KeyError, key: key, term: dict
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end
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end
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def has_key?(dict, key) do
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match? {:ok, _}, fetch(dict, key)
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end
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def put_new(dict, key, value) do
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case has_key?(dict, key) do
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true -> dict
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false -> put(dict, key, value)
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end
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end
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def drop(dict, keys) do
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Enum.reduce(keys, dict, &delete(&2, &1))
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end
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def take(dict, keys) do
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Enum.reduce(keys, new, fn key, acc ->
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case fetch(dict, key) do
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{:ok, value} -> put(acc, key, value)
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:error -> acc
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end
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end)
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end
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def to_list(dict) do
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reduce(dict, {:cont, []}, fn
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kv, acc -> {:cont, [kv|acc]}
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end) |> elem(1) |> :lists.reverse
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end
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def keys(dict) do
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reduce(dict, {:cont, []}, fn
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{k, _}, acc -> {:cont, [k|acc]}
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end) |> elem(1) |> :lists.reverse
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end
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def values(dict) do
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reduce(dict, {:cont, []}, fn
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{_, v}, acc -> {:cont, [v|acc]}
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end) |> elem(1) |> :lists.reverse
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end
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def equal?(dict1, dict2) do
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# Use this import to avoid conflicts in the user code
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import Kernel, except: [size: 1]
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case size(dict1) == size(dict2) do
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false -> false
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true ->
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reduce(dict1, {:cont, true}, fn({k, v}, _acc) ->
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case fetch(dict2, k) do
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{:ok, ^v} -> {:cont, true}
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_ -> {:halt, false}
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end
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end) |> elem(1)
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end
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end
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def merge(dict1, dict2, fun \\ fn(_k, _v1, v2) -> v2 end) do
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# Use this import to avoid conflicts in the user code
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import Kernel, except: [size: 1]
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if size(dict1) < size(dict2) do
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reduce(dict1, {:cont, dict2}, fn {k, v1}, acc ->
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{:cont, update(acc, k, v1, &fun.(k, v1, &1))}
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end)
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else
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reduce(dict2, {:cont, dict1}, fn {k, v2}, acc ->
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{:cont, update(acc, k, v2, &fun.(k, &1, v2))}
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end)
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end |> elem(1)
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end
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def update(dict, key, initial, fun) do
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case fetch(dict, key) do
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{:ok, value} ->
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put(dict, key, fun.(value))
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:error ->
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put(dict, key, initial)
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end
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end
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def update!(dict, key, fun) do
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case fetch(dict, key) do
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{:ok, value} ->
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put(dict, key, fun.(value))
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:error ->
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raise KeyError, key: key, term: dict
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end
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end
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def pop(dict, key, default \\ nil) do
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case fetch(dict, key) do
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{:ok, value} ->
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{value, delete(dict, key)}
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:error ->
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{default, dict}
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end
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end
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def split(dict, keys) do
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Enum.reduce(keys, {new, dict}, fn key, {inc, exc} = acc ->
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case fetch(exc, key) do
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{:ok, value} ->
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{put(inc, key, value), delete(exc, key)}
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:error ->
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acc
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end
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end)
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end
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defoverridable merge: 2, merge: 3, equal?: 2, to_list: 1, keys: 1,
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values: 1, take: 2, drop: 2, get: 2, get: 3, fetch!: 2,
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has_key?: 2, put_new: 3, pop: 2, pop: 3, split: 2,
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update: 4, update!: 3
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end
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end
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defmacrop target(dict) do
67271
quote do
68272
case unquote(dict) do

‎lib/elixir/lib/dict/behaviour.ex‎

Lines changed: 1 addition & 126 deletions
Original file line numberDiff line numberDiff line change
@@ -2,133 +2,8 @@ defmodule Dict.Behaviour do
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@moduledoc false
33

44
defmacro __using__(_) do
5-
# Use this import to guarantee proper code expansion
6-
import Kernel, except: [size: 1]
7-
85
quote do
9-
@behaviour Dict
10-
11-
def get(dict, key, default \\ nil) do
12-
case fetch(dict, key) do
13-
{:ok, value} -> value
14-
:error -> default
15-
end
16-
end
17-
18-
def fetch!(dict, key) do
19-
case fetch(dict, key) do
20-
{:ok, value} -> value
21-
:error -> raise KeyError, key: key, term: dict
22-
end
23-
end
24-
25-
def has_key?(dict, key) do
26-
match? {:ok, _}, fetch(dict, key)
27-
end
28-
29-
def put_new(dict, key, value) do
30-
update(dict, key, value, fn(v) -> v end)
31-
end
32-
33-
def drop(dict, keys) do
34-
Enum.reduce keys, dict, &delete(&2, &1)
35-
end
36-
37-
def take(dict, keys) do
38-
Enum.reduce keys, new, fn key, acc ->
39-
case fetch(dict, key) do
40-
{:ok, value} -> put(acc, key, value)
41-
:error -> acc
42-
end
43-
end
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end
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def to_list(dict) do
47-
reduce(dict, {:cont, []}, fn
48-
kv, acc -> {:cont, [kv|acc]}
49-
end) |> elem(1) |> :lists.reverse
50-
end
51-
52-
def keys(dict) do
53-
reduce(dict, {:cont, []}, fn
54-
{k, _}, acc -> {:cont, [k|acc]}
55-
end) |> elem(1) |> :lists.reverse
56-
end
57-
58-
def values(dict) do
59-
reduce(dict, {:cont, []}, fn
60-
{_, v}, acc -> {:cont, [v|acc]}
61-
end) |> elem(1) |> :lists.reverse
62-
end
63-
64-
def equal?(dict1, dict2) do
65-
# Use this import to avoid conflicts in the user code
66-
import Kernel, except: [size: 1]
67-
68-
case size(dict1) == size(dict2) do
69-
false -> false
70-
true ->
71-
reduce(dict1, {:cont, true}, fn({k, v}, _acc) ->
72-
case fetch(dict2, k) do
73-
{:ok, ^v} -> {:cont, true}
74-
_ -> {:halt, false}
75-
end
76-
end) |> elem(1)
77-
end
78-
end
79-
80-
def merge(dict1, dict2, fun \\ fn(_k, _v1, v2) -> v2 end) do
81-
reduce(dict1, {:cont, dict2}, fn {k, v1}, acc ->
82-
{:cont, update(acc, k, v1, &fun.(k, v1, &1))}
83-
end) |> elem(1)
84-
end
85-
86-
def update(dict, key, initial, fun) do
87-
case fetch(dict, key) do
88-
{ :ok, value } ->
89-
put(dict, key, fun.(value))
90-
91-
:error ->
92-
put(dict, key, initial)
93-
end
94-
end
95-
96-
def update!(dict, key, fun) do
97-
case fetch(dict, key) do
98-
{ :ok, value } ->
99-
put(dict, key, fun.(value))
100-
101-
:error ->
102-
raise KeyError, key: key, term: dict
103-
end
104-
end
105-
106-
def pop(dict, key, default \\ nil) do
107-
case fetch(dict, key) do
108-
{ :ok, value } ->
109-
{ value, delete(dict, key) }
110-
111-
:error ->
112-
{ default, dict }
113-
end
114-
end
115-
116-
def split(dict, keys) do
117-
Enum.reduce keys, { new, dict }, fn key, { inc, exc } = acc ->
118-
case fetch(exc, key) do
119-
{ :ok, value } ->
120-
{ put(inc, key, value), delete(exc, key) }
121-
122-
:error ->
123-
acc
124-
end
125-
end
126-
end
127-
128-
defoverridable merge: 2, merge: 3, equal?: 2, to_list: 1, keys: 1,
129-
values: 1, take: 2, drop: 2, get: 2, get: 3, fetch!: 2,
130-
has_key?: 2, put_new: 3, pop: 2, pop: 3, update: 4, update!: 3,
131-
split: 2
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use Dict
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end
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end
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end

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