Additional maps

2 files changed, 132 insertions, 6 deletions

diff --git a/src/gleam__stdlib.erl b/src/gleam__stdlib.erl
index db80c1b..5942a0f 100644
--- a/src/gleam__stdlib.erl
+++ b/src/gleam__stdlib.erl
@@ -6,3 +6,9 @@ expect_equal(A, Expected) -> ?assertEqual(Expected, A).
 expect_not_equal(A, Expected) -> ?assertNotEqual(Expected, A).
 expect_true(A) -> ?assert(A).
 expect_false(A) -> ?assertNot(A).
+
+map_fetch(Map, Key) ->
+  case maps:find(Key, Map) of
+    error -> {error, {}},
+    Found -> Found
+  end.
diff --git a/src/map.gleam b/src/map.gleam
index 0e41aa7..032ef90 100644
--- a/src/map.gleam
+++ b/src/map.gleam
@@ -1,4 +1,5 @@
 import any
+import result:Result
 import expect
 
 pub external type Map(key, value);
@@ -21,12 +22,17 @@ test size {
     |> size
     |> expect:equal(_, 0)
 
-  [{1, 1}]
+  [
+    {1, 1},
+  ]
     |> from_list
     |> size
     |> expect:equal(_, 1)
 
-  [{"", 1.0}, {"", 2.0}]
+  [
+    {"", 1.0},
+    {"", 2.0},
+  ]
     |> from_list
     |> size
     |> expect:equal(_, 2)
@@ -45,17 +51,25 @@ test has_key {
     |> has_key(_, 1)
     |> expect:false
 
-  [{1, 0}]
+  [
+    {1, 0},
+  ]
     |> from_list
     |> has_key(_, 1)
     |> expect:true
 
-  [{4, 0}, {1, 0}]
+  [
+    {4, 0},
+    {1, 0},
+  ]
     |> from_list
     |> has_key(_, 1)
     |> expect:true
 
-  [{4, 0}, {1, 0}]
+  [
+    {4, 0},
+    {1, 0},
+  ]
     |> from_list
     |> has_key(_, 0)
     |> expect:false
@@ -83,7 +97,10 @@ pub external fn from_list(List(Tuple(key, value))) -> Map(key, value)
   = 'maps' 'from_list'
 
 test from_list {
-  proplist = [{4, 0}, {1, 0}]
+  proplist = [
+    {4, 0},
+    {1, 0},
+  ]
   map = from_list(proplist)
 
   map
@@ -94,3 +111,106 @@ test from_list {
     |> to_list
     |> expect:equal(_, proplist)
 }
+
+pub external fn fetch(Map(key, value), key) -> Result(Unit, value)
+  = 'gleam__stdlib' 'map_fetch';
+
+test fetch {
+  proplist = [
+    {4, 0},
+    {1, 1},
+  ]
+  map = from_list(proplist)
+
+  map
+    |> fetch(_, 4)
+    |> expect:equal(_, result:Ok(0))
+
+  map
+    |> fetch(_, 1)
+    |> expect:equal(_, result:Ok(1))
+
+  map
+    |> fetch(_, 2)
+    |> expect:equal(_, result:Error(()))
+}
+
+external fn erl_put(key, value, Map(key, value)) -> Map(key, value)
+  = 'maps' 'put';
+
+pub fn put(map, key, value) {
+  erl_put(key, value, map)
+}
+
+test put {
+  new()
+    |> put(_, 'a', 0)
+    |> put(_, 'b', 1)
+    |> put(_, 'c', 2)
+    |> expect:equal(_, result:Ok(from_list([{'a', 0}, {'b', 1}, {'c', 2}])))
+}
+
+external fn erl_map_values(fn(key, value) -> value, Map(key, value)) -> Map(key, value)
+  = 'maps' 'map';
+
+pub fn map_values(map, fun) {
+  erl_map_values(fun, map)
+}
+
+test map_values {
+  [
+    {1, 0},
+    {2, 1},
+    {3, 2},
+  ]
+    |> from_list
+    |> map_values(_, fn(k, v) { k + v })
+    |> expect:equal(_, from_list([{1, 0}, {2, 3}, {3, 5}]))
+}
+
+pub external fn keys(Map(keys, _)) -> List(keys)
+  = 'maps' 'keys'
+
+test keys {
+  [
+    {'a', 0},
+    {'b', 1},
+    {'c', 2},
+  ]
+    |> from_list
+    |> keys
+    |> expect:equal(_, ['a', 'b', 'c']))
+}
+
+pub external fn values(Map(_, values)) -> List(values)
+  = 'maps' 'values'
+
+test values {
+  [
+    {'a', 0},
+    {'b', 1},
+    {'c', 2},
+  ]
+    |> from_list
+    |> values
+    |> expect:equal(_, [0, 1, 2]))
+}
+
+external fn erl_filter(fn(key, value) -> Bool, Map(key, value)) -> Map(key, value)
+  = 'maps' 'filter';
+
+pub fn filter(map, fun) {
+  filter(fun, map)
+}
+
+test map_values {
+  [
+    {1, 0},
+    {3, 2},
+    {2, 1},
+  ]
+    |> from_list
+    |> filter(_, fn(k, v) { k + v < 4 })
+    |> expect:equal(_, from_list([{1, 0}, {2, 3}]))
+}
+