implement set operations on dict

crates/compiler/builtins/roc/Dict.roc

@@ -151,7 +151,7 @@ values = \@Dict list ->
 # union : Dict k v, Dict k v -> Dict k v
 insertAll : Dict k v, Dict k v -> Dict k v
 insertAll = \xs, @Dict ys ->
-    List.walk ys xs (\state, Pair k v -> Dict.insert state k v)
+    List.walk ys xs (\state, Pair k v -> Dict.insertIfVacant state k v)
 
 # intersection : Dict k v, Dict k v -> Dict k v
 keepShared : Dict k v, Dict k v -> Dict k v
@@ -172,3 +172,10 @@ insertFresh = \@Dict list, k, v ->
     list
         |> List.append (Pair k v)
         |> @Dict
+
+insertIfVacant : Dict k v, k, v -> Dict k v
+insertIfVacant = \dict, key, value ->
+    if Dict.contains dict key then
+        dict
+    else
+        Dict.insert dict key value

crates/compiler/module/src/symbol.rs

@@ -1315,12 +1315,11 @@ define_builtins! {
         10 DICT_KEYS: "keys"
         11 DICT_VALUES: "values"
 
-        12 DICT_UNION: "union"
+        12 DICT_INSERT_ALL: "insertAll" // union
-        13 DICT_INTERSECTION: "intersection"
+        13 DICT_KEEP_SHARED: "keepShared" // intersection
-        14 DICT_DIFFERENCE: "difference"
+        14 DICT_REMOVE_ALL: "removeAll" // difference
 
-        15 DICT_GET_LOWLEVEL: "getLowlevel"
+        15 DICT_WITH_CAPACITY: "withCapacity"
-        16 DICT_WITH_CAPACITY: "withCapacity"
     }
     8 SET: "Set" => {
         0 SET_SET: "Set" // the Set.Set type alias

crates/compiler/test_gen/src/gen_dict.rs

@@ -404,7 +404,7 @@ fn single() {
 
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
-fn union() {
+fn insert_all() {
     assert_evals_to!(
         indoc!(
             r#"
@@ -412,7 +412,7 @@ fn union() {
 
             myDict : Dict.Dict I64 {}
             myDict =
-                Dict.union (Dict.single 0 {}) (Dict.single 1 {})
+                Dict.insertAll (Dict.single 0 {}) (Dict.single 1 {})
 
             main = Dict.len myDict
             "#
@@ -424,7 +424,7 @@ fn union() {
 
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
-fn union_prefer_first() {
+fn insert_all_prefer_first() {
     assert_evals_to!(
         indoc!(
             r#"
@@ -432,7 +432,8 @@ fn union_prefer_first() {
 
             myDict : Dict.Dict I64 I64
             myDict =
-                Dict.union (Dict.single 0 100) (Dict.single 0 200)
+                (Dict.single 0 100)
+                    |> Dict.insertAll (Dict.single 0 200)
 
             main = Dict.values myDict
             "#
@@ -444,7 +445,7 @@ fn union_prefer_first() {
 
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
-fn intersection() {
+fn keep_shared() {
     assert_evals_to!(
         indoc!(
             r#"
@@ -467,7 +468,7 @@ fn intersection() {
                     |> Dict.insert 4 {}
 
             main =
-                Dict.intersection dict1 dict2
+                Dict.keepShared dict1 dict2
                     |> Dict.len
             "#
         ),
@@ -478,7 +479,7 @@ fn intersection() {
 
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
-fn intersection_prefer_first() {
+fn keep_shared_prefer_first() {
     assert_evals_to!(
         indoc!(
             r#"
@@ -501,18 +502,18 @@ fn intersection_prefer_first() {
                     |> Dict.insert 4 300
 
             main =
-                Dict.intersection dict1 dict2
+                Dict.keepShared dict1 dict2
                     |> Dict.values
             "#
         ),
-        RocList::from_slice(&[4, 2]),
+        RocList::from_slice(&[2, 4]),
         RocList<i64>
     );
 }
 
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
-fn difference() {
+fn remove_all() {
     assert_evals_to!(
         indoc!(
             r#"
@@ -535,7 +536,7 @@ fn difference() {
                     |> Dict.insert 4 {}
 
             main =
-                Dict.difference dict1 dict2
+                Dict.removeAll dict1 dict2
                     |> Dict.len
             "#
         ),
@@ -546,7 +547,7 @@ fn difference() {
 
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
-fn difference_prefer_first() {
+fn remove_all_prefer_first() {
     assert_evals_to!(
         indoc!(
             r#"
@@ -569,11 +570,11 @@ fn difference_prefer_first() {
                     |> Dict.insert 4 300
 
             main =
-                Dict.difference dict1 dict2
+                Dict.removeAll dict1 dict2
                     |> Dict.values
             "#
         ),
-        RocList::from_slice(&[5, 3, 1]),
+        RocList::from_slice(&[1, 5, 3]),
         RocList<i64>
     );
 }