map:take

5 files changed, 75 insertions, 46 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 98070e6..33257e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,8 +5,8 @@
 - `list` module gains `at`, `all`, `any`, `index_map`, `intersperse`, `sort`,
   `unique`, and `zip` functions.
 - `map_dict:Map` renamed to `map_dict:MapDict`.
-- `map_dict` module gains `take`.
-- `str` module gains `append`.
+- `map_dict` module gains `drop`, and `take` functions.
+- `str` module gains `append` function.
 
 ## v0.1.1 - 2019-04-17
 
diff --git a/gen/src/map_dict.erl b/gen/src/map_dict.erl
index eefdfc3..7d97a7d 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]).
+-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]).
 
 size(A) ->
     maps:size(A).
@@ -53,3 +53,9 @@ erl_take(A, B) ->
 
 take(Map, Keys) ->
     erl_take(Keys, Map).
+
+erl_drop(A, B) ->
+    maps:without(A, B).
+
+drop(Map, Keys) ->
+    erl_drop(Keys, Map).
diff --git a/gen/test/map_dict_test.erl b/gen/test/map_dict_test.erl
index a5a0d8a..e59911e 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]).
+-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]).
 
 from_list_test() ->
     expect:equal(map_dict:size(map_dict:from_list([{4, 0}, {1, 0}])), 2).
@@ -60,3 +60,10 @@ take_test() ->
                                                    {<<"c">>, 2}]),
                                [<<"a">>, <<"b">>, <<"d">>]),
                  map_dict:from_list([{<<"a">>, 0}, {<<"b">>, 1}])).
+
+drop_test() ->
+    expect:equal(map_dict:drop(map_dict:from_list([{<<"a">>, 0},
+                                                   {<<"b">>, 1},
+                                                   {<<"c">>, 2}]),
+                               [<<"a">>, <<"b">>, <<"d">>]),
+                 map_dict:from_list([{<<"c">>, 2}])).
diff --git a/src/map_dict.gleam b/src/map_dict.gleam
index 489b260..7dd00e6 100644
--- a/src/map_dict.gleam
+++ b/src/map_dict.gleam
@@ -1,7 +1,6 @@
 import any
 import result
 
-// TODO: drop
 // TODO: update :: fn(MapDict(k, v), k, fn(Result(v, NotFound)) -> v) -> MapDict(k, v)
 
 pub external type MapDict(key, value);
@@ -65,3 +64,9 @@ external fn erl_take(List(k), MapDict(k, v)) -> MapDict(k, v) = "maps" "with"
 pub fn take(map, keys) {
   erl_take(keys, map)
 }
+
+external fn erl_drop(List(k), MapDict(k, v)) -> MapDict(k, v) = "maps" "without"
+
+pub fn drop(map, keys) {
+  erl_drop(keys, map)
+}
diff --git a/test/map_dict_test.gleam b/test/map_dict_test.gleam
index f72e23a..a0797c2 100644
--- a/test/map_dict_test.gleam
+++ b/test/map_dict_test.gleam
@@ -6,49 +6,49 @@ pub fn from_list_test() {
     {4, 0},
     {1, 0},
   ]
-    |> map_dict:from_list
-    |> map_dict:size
-    |> expect:equal(_, 2)
+  |> map_dict:from_list
+  |> map_dict:size
+  |> expect:equal(_, 2)
 }
 
 pub fn has_key_test() {
   []
-    |> map_dict:from_list
-    |> map_dict:has_key(_, 1)
-    |> expect:false
+  |> map_dict:from_list
+  |> map_dict:has_key(_, 1)
+  |> expect:false
 
   [
       {1, 0},
   ]
-    |> map_dict:from_list
-    |> map_dict:has_key(_, 1)
-    |> expect:true
+  |> map_dict:from_list
+  |> map_dict:has_key(_, 1)
+  |> expect:true
 
   [
       {4, 0},
       {1, 0},
   ]
-    |> map_dict:from_list
-    |> map_dict:has_key(_, 1)
-    |> expect:true
+  |> map_dict:from_list
+  |> map_dict:has_key(_, 1)
+  |> expect:true
 
   [
     {4, 0},
     {1, 0},
   ]
-    |> map_dict:from_list
-    |> map_dict:has_key(_, 0)
-    |> expect:false
+  |> map_dict:from_list
+  |> map_dict:has_key(_, 0)
+  |> expect:false
 }
 
 pub fn new_test() {
   map_dict:new()
-    |> map_dict:size
-    |> expect:equal(_, 0)
+  |> map_dict:size
+  |> expect:equal(_, 0)
 
   map_dict:new()
-    |> map_dict:to_list
-    |> expect:equal(_, [])
+  |> map_dict:to_list
+  |> expect:equal(_, [])
 }
 
 pub fn fetch_test() {
@@ -59,24 +59,24 @@ pub fn fetch_test() {
   let m = map_dict:from_list(proplist)
 
   m
-    |> map_dict:fetch(_, 4)
-    |> expect:equal(_, Ok(0))
+  |> map_dict:fetch(_, 4)
+  |> expect:equal(_, Ok(0))
 
   m
-    |> map_dict:fetch(_, 1)
-    |> expect:equal(_, Ok(1))
+  |> map_dict:fetch(_, 1)
+  |> expect:equal(_, Ok(1))
 
   m
-    |> map_dict:fetch(_, 2)
-    |> expect:is_error
+  |> map_dict:fetch(_, 2)
+  |> expect:is_error
 }
 
 pub fn put_test() {
   map_dict:new()
-    |> map_dict:put(_, "a", 0)
-    |> map_dict:put(_, "b", 1)
-    |> map_dict:put(_, "c", 2)
-    |> expect:equal(_, map_dict:from_list([{"a", 0}, {"b", 1}, {"c", 2}]))
+  |> map_dict:put(_, "a", 0)
+  |> map_dict:put(_, "b", 1)
+  |> map_dict:put(_, "c", 2)
+  |> expect:equal(_, map_dict:from_list([{"a", 0}, {"b", 1}, {"c", 2}]))
 }
 
 pub fn map_values_test() {
@@ -85,9 +85,9 @@ pub fn map_values_test() {
     {2, 1},
     {3, 2},
   ]
-    |> map_dict:from_list
-    |> map_dict:map_values(_, fn(k, v) { k + v })
-    |> expect:equal(_, map_dict:from_list([{1, 1}, {2, 3}, {3, 5}]))
+  |> map_dict:from_list
+  |> map_dict:map_values(_, fn(k, v) { k + v })
+  |> expect:equal(_, map_dict:from_list([{1, 1}, {2, 3}, {3, 5}]))
 }
 
 pub fn keys_test() {
@@ -96,9 +96,9 @@ pub fn keys_test() {
     {"b", 1},
     {"c", 2},
   ]
-    |> map_dict:from_list
-    |> map_dict:keys
-    |> expect:equal(_, ["a", "b", "c"])
+  |> map_dict:from_list
+  |> map_dict:keys
+  |> expect:equal(_, ["a", "b", "c"])
 }
 
 pub fn values_test() {
@@ -107,9 +107,9 @@ pub fn values_test() {
     {"b", 1},
     {"c", 2},
   ]
-    |> map_dict:from_list
-    |> map_dict:values
-    |> expect:equal(_, [0, 1, 2])
+  |> map_dict:from_list
+  |> map_dict:values
+  |> expect:equal(_, [0, 1, 2])
 }
 
 pub fn take_test() {
@@ -118,7 +118,18 @@ pub fn take_test() {
     {"b", 1},
     {"c", 2},
   ]
-    |> map_dict:from_list
-    |> map_dict:take(_, ["a", "b", "d"])
-    |> expect:equal(_, map_dict:from_list([{"a", 0}, {"b", 1}]))
+  |> map_dict:from_list
+  |> map_dict:take(_, ["a", "b", "d"])
+  |> expect:equal(_, map_dict:from_list([{"a", 0}, {"b", 1}]))
+}
+
+pub fn drop_test() {
+  [
+    {"a", 0},
+    {"b", 1},
+    {"c", 2},
+  ]
+  |> map_dict:from_list
+  |> map_dict:drop(_, ["a", "b", "d"])
+  |> expect:equal(_, map_dict:from_list([{"c", 2}]))
 }