map_dict:delete

5 files changed, 38 insertions, 7 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9e9cdf3..30c771d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ## Unreleased
 
-- `map_dict` module gains `merge` function.
+- `map_dict` module gains `merge` and `delete` functions.
 
 ## v0.1.2 - 2019-04-25
 
diff --git a/gen/src/map_dict.erl b/gen/src/map_dict.erl
index dcff286..0eea5c2 100644
--- a/gen/src/map_dict.erl
+++ b/gen/src/map_dict.erl
@@ -1,7 +1,7 @@
 -module(map_dict).
 -compile(no_auto_import).
 
--export([size/1, to_list/1, from_list/1, has_key/2, new/0, fetch/2, put/3, map_values/2, keys/1, values/1, filter/2, take/2, drop/2, merge/2]).
+-export([size/1, to_list/1, from_list/1, has_key/2, new/0, fetch/2, put/3, map_values/2, keys/1, values/1, filter/2, take/2, drop/2, merge/2, delete/2]).
 
 size(A) ->
     maps:size(A).
@@ -62,3 +62,9 @@ drop(Map, Keys) ->
 
 merge(A, B) ->
     maps:merge(A, B).
+
+erl_delete(A, B) ->
+    maps:remove(A, B).
+
+delete(Map, Key) ->
+    erl_delete(Key, Map).
diff --git a/gen/test/map_dict_test.erl b/gen/test/map_dict_test.erl
index 20be544..4470b14 100644
--- a/gen/test/map_dict_test.erl
+++ b/gen/test/map_dict_test.erl
@@ -1,7 +1,7 @@
 -module(map_dict_test).
 -compile(no_auto_import).
 
--export([from_list_test/0, has_key_test/0, new_test/0, fetch_test/0, put_test/0, map_values_test/0, keys_test/0, values_test/0, take_test/0, drop_test/0, merge_test/0]).
+-export([from_list_test/0, has_key_test/0, new_test/0, fetch_test/0, put_test/0, map_values_test/0, keys_test/0, values_test/0, take_test/0, drop_test/0, merge_test/0, delete_test/0]).
 
 from_list_test() ->
     expect:equal(map_dict:size(map_dict:from_list([{4, 0}, {1, 0}])), 2).
@@ -81,3 +81,14 @@ merge_test() ->
                                      {<<"b">>, 1},
                                      {<<"c">>, 4},
                                      {<<"d">>, 3}])).
+
+delete_test() ->
+    expect:equal(map_dict:delete(map_dict:delete(map_dict:from_list([{<<"a">>,
+                                                                      0},
+                                                                     {<<"b">>,
+                                                                      1},
+                                                                     {<<"c">>,
+                                                                      2}]),
+                                                 <<"a">>),
+                                 <<"d">>),
+                 map_dict:from_list([{<<"b">>, 1}, {<<"c">>, 2}])).
diff --git a/src/map_dict.gleam b/src/map_dict.gleam
index e702f89..3c49aa5 100644
--- a/src/map_dict.gleam
+++ b/src/map_dict.gleam
@@ -3,10 +3,6 @@ import result
 
 // TODO: update :: fn(MapDict(k, v), k, fn(Result(v, NotFound)) -> v) -> MapDict(k, v)
 // TODO: delete :: fn(MapDict(k, v), k) -> MapDict(k, v)
-// TODO: is_disjoint
-// TODO: is_subset
-// TODO: difference
-// TODO: intersection
 
 pub external type MapDict(key, value);
 
@@ -77,3 +73,9 @@ pub fn drop(map, keys) {
 }
 
 pub external fn merge(MapDict(k, v), MapDict(k, v)) -> MapDict(k, v) = "maps" "merge"
+
+external fn erl_delete(k, MapDict(k, v)) -> MapDict(k, v) = "maps" "remove"
+
+pub fn delete(map, key) {
+  erl_delete(key, map)
+}
diff --git a/test/map_dict_test.gleam b/test/map_dict_test.gleam
index 1ee489a..359df7c 100644
--- a/test/map_dict_test.gleam
+++ b/test/map_dict_test.gleam
@@ -162,3 +162,15 @@ pub fn merge_test() {
       {"d", 3},
     ]))
 }
+
+pub fn delete_test() {
+  [
+    {"a", 0},
+    {"b", 1},
+    {"c", 2},
+  ]
+  |> map_dict:from_list
+  |> map_dict:delete(_, "a")
+  |> map_dict:delete(_, "d")
+  |> expect:equal(_, map_dict:from_list([{"b", 1}, {"c", 2}]))
+}