From 9f27dab9b5b8b5b981b7dc40863b688d1d12b795 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 26 Jan 2022 11:46:41 +0000
Subject: [PATCH 01/20] Expanded benchmarks

---
 test/Benchmarks/src/Vector.enso | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/test/Benchmarks/src/Vector.enso b/test/Benchmarks/src/Vector.enso
index 1138d781a016..55ec7df69229 100644
--- a/test/Benchmarks/src/Vector.enso
+++ b/test/Benchmarks/src/Vector.enso
@@ -21,8 +21,18 @@ make_random_vec n =
 
 main =
     random_vec = here.make_random_vec here.vector_size
-
+    random_vec_2 = here.make_random_vec 100000
+
+    Bench.measure (Base.Vector.new here.vector_size i->i) "New Vector" here.iter_size here.num_iterations
+    Bench.measure (random_vec + [1]) "Append Single" here.iter_size here.num_iterations
+    Bench.measure (random_vec + random_vec_2) "Append Large" here.iter_size here.num_iterations
+    Bench.measure (random_vec.sum) "Sum" here.iter_size here.num_iterations
+    Bench.measure ((random_vec.drop_start 20).sum) "Drop First 20 and Sum" here.iter_size here.num_iterations
+    Bench.measure ((random_vec.drop_end 20).sum) "Drop Last 20 and Sum" here.iter_size here.num_iterations
     Bench.measure (random_vec.filter (x -> x % 3 == 1)) "Filter" here.iter_size here.num_iterations
+    Bench.measure (random_vec.filter_with_index (i->x -> (i+x) % 3 == 1)) "Filter With Index" here.iter_size here.num_iterations
+    Bench.measure (random_vec.partition (x -> x % 3 == 1)) "Partition" here.iter_size here.num_iterations
+    Bench.measure (random_vec.partition_with_index (i->x -> (i+x) % 3 == 1)) "Partition With Index" here.iter_size here.num_iterations
 
     stateful_fun x =
        s = State.get Number

From 8ca19369d3eda5b97ea7c9cff1edfd0e3eddcadf Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 26 Jan 2022 12:42:19 +0000
Subject: [PATCH 02/20] Update Builder and append

---
 .../Base/0.0.0-dev/src/Data/Vector.enso       | 24 +++++--------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 14243fb6d3c7..786f8f34b691 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -231,10 +231,7 @@ type Vector
              [1, 2, 3, 4, 5].exists (> 3)
     exists : (Any -> Boolean) -> Boolean
     exists predicate =
-        len = this.length
-        go idx found = if found || (idx >= len) then found else
-            @Tail_Call go idx+1 (predicate (this.unsafe_at idx))
-        go 0 False
+        0.up_to this.length . exists (idx -> (predicate (this.unsafe_at idx)))
 
     ## Returns the first element of the vector that satisfies the predicate or
        if no elements of the vector satisfy the predicate, it throws nothing.
@@ -572,10 +569,8 @@ type Vector
     + that =
         this_len = this.length
         arr = Array.new (this_len + that.length)
-        0.up_to this_len . each i->
-            arr.set_at i (this.unsafe_at i)
-        this.length.up_to arr.length . each i->
-            arr.set_at i (that.unsafe_at i-this_len)
+        Array.copy this.to_array 0 arr 0 this_len
+        Array.copy that.to_array 0 arr this_len that.length
         Vector arr
 
     ## Add `element` to the beginning of `this` vector.
@@ -1027,9 +1022,7 @@ type Builder
         False ->
             old_array = this.to_array
             new_array = Array.new old_array.length*2
-            0.up_to this.length . each i->
-                new_array.set_at i (old_array.at i)
-                Nothing
+            Array.copy old_array 0 new_array 0 old_array.length
             Unsafe.set_atom_field this 0 new_array
             this.append item
             Nothing
@@ -1042,10 +1035,7 @@ type Builder
 
     exists : (Any -> Boolean) -> Boolean
     exists predicate =
-        len = this.length
-        go idx found = if found || (idx >= len) then found else
-            @Tail_Call go idx+1 (predicate (this.to_array.at idx))
-        go 0 False
+        0.up_to this.length . exists (idx -> (predicate (this.to_array.at idx)))
 
     ## Converts this builder to a vector containing all the appended elements.
 
@@ -1062,9 +1052,7 @@ type Builder
     to_vector =
         old_array = this.to_array
         new_array = Array.new this.length
-        0.up_to this.length . each i->
-            new_array.set_at i (old_array.at i)
-            Nothing
+        Array.copy old_array 0 new_array 0 this.length
         Vector new_array
 
 ## UNSTABLE

From 1879cc4732557d8ffa478aa665b117d8f6525ea9 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 26 Jan 2022 14:47:18 +0000
Subject: [PATCH 03/20] Slice, Take, Drop... Tweak for reduce and all

---
 .../Base/0.0.0-dev/src/Data/Vector.enso       | 39 ++++++++++++++-----
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 786f8f34b691..7ed3d46c73fe 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -198,7 +198,10 @@ type Vector
     reduce : (Any -> Any -> Any) -> Any ! Empty_Error
     reduce function =
         case this.not_empty of
-            True -> this.tail.fold this.head function
+            True -> if this.length == 1 then this.unsafe_at 0 else
+                arr = this.to_array
+                f = acc -> ix -> function acc (arr.at ix)
+                1.up_to this.length . fold (this.unsafe_at 0) f
             False -> Error.throw Empty_Error
 
     ## Computes the sum of the values in the vector.
@@ -281,7 +284,7 @@ type Vector
 
              [-1, 1, 5, 8].all (< 0)
     all : (Any -> Boolean) -> Boolean
-    all predicate = this.fold True (l -> r -> l && predicate r)
+    all predicate = (this.exists (r -> (predicate r).not)).not
 
     ## Checks whether this vector contains a given value as an element.
 
@@ -615,6 +618,26 @@ type Vector
             if this.length == 1 then prefix + this.unsafe_at 0 + suffix else
                 prefix + this.unsafe_at 0 + (1.up_to this.length . fold "" acc-> i-> acc + separator + this.unsafe_at i) + suffix
 
+    ## Creates a new vector with the skipping elements until `start` and then
+       continuing for `length` elements.
+
+       Arguments:
+       - start: The number of elements to drop from the start of `this`.
+       - length: The number of elements for the sub-vector.
+
+       > Example
+         Remove the first 2 elements then take 5 from the vector.
+
+             [1, 2, 3, 4, 5, 6, 7, 8].slice 2 5
+    slice : Integer -> Integer -> Vector Any
+    slice start length =
+        if start > this.length then Vector (Array.new 0) else
+            slice_length = Math.min (this.length - start) length
+            if slice_length == 0 then Vector (Array.new 0) else
+                new_array = Array.new slice_length
+                Array.Copy this.to_array start new_array 0 slice_length
+                Vector new_array
+
     ## Creates a new vector with the first `count` elements in `this` removed.
 
        Arguments:
@@ -625,8 +648,7 @@ type Vector
 
              [1, 2, 3, 4, 5].drop_start 1
     drop_start : Integer -> Vector Any
-    drop_start count = if count >= this.length then here.new 0 (x -> x) else
-        here.new (this.length - count) (i -> this.unsafe_at i+count)
+    drop_start count = this.slice count (this.length - count)
 
     ## Creates a new vector with the last `count` elements in `this` removed.
 
@@ -638,8 +660,7 @@ type Vector
 
              [1, 2, 3, 4, 5].drop_end 2
     drop_end : Integer -> Vector Any
-    drop_end count = if count >= this.length then here.new 0 (x -> x) else
-        this.take_start (this.length - count)
+    drop_end count = this.slice 0 (this.length - count)
 
     ## Creates a new vector, consisting of the first `count` elements on the
        left of `this`.
@@ -652,8 +673,7 @@ type Vector
 
              [1, 2, 3, 4, 5].take_start 2
     take_start : Integer -> Vector Any
-    take_start count = if count >= this.length then this else
-        here.new count this.at
+    take_start count = this.slice 0 count
 
     ## Creates a new vector, consisting of the last `count` elements on the
        right of `this`.
@@ -666,8 +686,7 @@ type Vector
 
              [1, 2, 3, 4, 5].take_end 3
     take_end : Integer -> Vector Any
-    take_end count = if count >= this.length then this else
-        this.drop_start (this.length - count)
+    take_end count = this.slice (this.length - count) count
 
     ## Performs a pair-wise operation passed in `function` on consecutive
        elements of `this` and `that`.

From f6e2978424ecb5002e6c1591972b23efb95d5400 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 26 Jan 2022 17:39:03 +0000
Subject: [PATCH 04/20] Each With Index Filter and Partition tweaks

---
 .../Base/0.0.0-dev/src/Data/Vector.enso       | 68 +++++++++++++------
 test/Tests/src/Data/Vector_Spec.enso          |  2 +
 2 files changed, 51 insertions(+), 19 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 7ed3d46c73fe..d262446b09db 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -184,6 +184,24 @@ type Vector
         f = acc -> ix -> function acc (arr.at ix)
         0.up_to this.length . fold init f
 
+    ## Combines all the elements of the vector, by iteratively applying the
+       passed function with next elements of the vector.
+
+       Arguments:
+       - init: The initial value for the fold.
+       - function: A function taking the current value, an index and an item
+         and combining them.
+
+       > Example
+         Compute the sum of all of the elements and indexes in a vector.
+
+             [0, 1, 2] . fold 0 (s->i->e->s+i+e)
+    fold_with_index : Any -> (Any -> Integer -> Any -> Any) -> Any
+    fold_with_index init function =
+        arr = this.to_array
+        f = acc -> ix -> function acc ix (arr.at ix)
+        0.up_to this.length . fold init f
+
     ## Combines all the elements of a non-empty vector using a binary operation.
 
        Arguments:
@@ -346,12 +364,8 @@ type Vector
              [0, 10, 2, 2].filter (==) == [0, 2]
     filter_with_index : (Integer -> Any -> Boolean) -> Vector Any
     filter_with_index predicate =
-        acc = this.fold (Pair here.new_builder 0) acc-> elem->
-            builder = acc.first
-            ix = acc.second
-            new_builder = if predicate ix elem then builder.append elem else builder
-            Pair new_builder ix+1
-        builder = acc.first
+        builder = this.fold_with_index here.new_builder builder-> ix-> elem->
+            if predicate ix elem then builder.append elem else builder
         builder.to_vector
 
     ## Partitions the vector into vectors of elements which satisfy a given
@@ -372,15 +386,15 @@ type Vector
          Splitting a vector into even and odd elements.
 
              [1, 2, 3, 4, 5].partition (x -> x % 2 == 0) == (Pair [2, 4] [1, 3, 5])
-    partition : (Any -> Boolean) -> Vector Any
+    partition : (Any -> Boolean) -> Pair Vector Any Vector Any
     partition predicate =
-        acc = this.fold (Pair here.new_builder here.new_builder) acc-> elem->
+        pair = this.fold (Pair here.new_builder here.new_builder) acc-> elem->
             case predicate elem of
                 True ->
                     Pair (acc.first.append elem) acc.second
                 False ->
                     Pair acc.first (acc.second.append elem)
-        acc.map .to_vector
+        pair.map .to_vector
 
     ## Partitions the vector into vectors of elements which satisfy a given
        predicate and ones that do not.
@@ -400,17 +414,13 @@ type Vector
          Splitting a vector into elements at even and odd positions.
 
              ["a", "b", "c", "d"].partition_with_index (ix -> _ -> ix % 2 == 0) == (Pair ["a", "c"] ["b", "d"])
-    partition_with_index : (Integer -> Any -> Boolean) -> Vector Any
+    partition_with_index : (Integer -> Any -> Boolean) -> Pair Vector Any Vector Any
     partition_with_index predicate =
-        acc = this.fold (Partition_Accumulator here.new_builder here.new_builder 0) acc-> elem->
-            case predicate acc.ix elem of
-                True ->
-                    Partition_Accumulator (acc.true_builder.append elem) acc.false_builder acc.ix+1
-                False ->
-                    Partition_Accumulator acc.true_builder (acc.false_builder.append elem) acc.ix+1
-        case acc of
-            Partition_Accumulator true_builder false_builder _ ->
-                Pair true_builder.to_vector false_builder.to_vector
+        pair = this.fold_with_index (Pair here.new_builder here.new_builder) acc-> ix-> elem->
+            case predicate ix elem of
+                True -> Pair (acc.first.append elem) acc.second
+                False -> Pair acc.first (acc.second.append elem)
+        pair.map .to_vector
 
     ## Applies a function to each element of the vector, returning the vector of
        results.
@@ -499,6 +509,26 @@ type Vector
         0.up_to this.length . each ix->
             f (this.unsafe_at ix)
 
+    ## Applies a function to each element of the vector.
+
+       Arguments:
+       - function: A function to apply that takes an index and an item.
+
+       The function is called with both the element index as well as the
+       element itself.
+
+       Unlike `map`, this method does not return the individual results,
+       therefore it is only useful for side-effecting computations.
+
+       > Example
+         Print each element in the vector to standard output.
+
+             [1, 2, 3, 4, 5] . each_with_index (ix->elem-> IO.println Pair ix elem)
+    each_with_index : (Integer -> Any -> Any) -> Nothing
+    each_with_index f =
+        0.up_to this.length . each ix->
+            f ix (this.unsafe_at ix)
+
     ## Reverses the vector, returning a vector with the same elements, but in
        the opposite order.
 
diff --git a/test/Tests/src/Data/Vector_Spec.enso b/test/Tests/src/Data/Vector_Spec.enso
index d1bea3fad323..b6f3098298bc 100644
--- a/test/Tests/src/Data/Vector_Spec.enso
+++ b/test/Tests/src/Data/Vector_Spec.enso
@@ -117,6 +117,8 @@ spec = Test.group "Vectors" <|
     Test.specify "should partition elements" <|
         [1, 2, 3, 4, 5].partition (x -> x % 2 == 0) . should_equal <| Pair [2, 4] [1, 3, 5]
         ([1, 2, 3, 4].partition x-> if x == 1 then Error.throw <| My_Error "foo" else True) . should_fail_with My_Error
+
+    Test.specify "should partition elements with indices" <|
         ["a", "b", "c", "d"].partition_with_index (ix -> _ -> ix % 2 == 0) == (Pair ["a", "c"] ["b", "d"])
         ["a", "b", "c", "d"].partition_with_index (ix -> _ -> if ix % 2 == 0 then Error.throw <| My_Error "foo" else True) . should_fail_with My_Error
 

From 4a38b5aea2c9c0cb47a943b99fa1aae8e876fae0 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Thu, 27 Jan 2022 22:02:42 +0000
Subject: [PATCH 05/20] Rename slice to take

---
 .../Base/0.0.0-dev/src/Data/Vector.enso       | 36 +++++++++----------
 test/Tests/src/Data/Vector_Spec.enso          |  1 +
 2 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index d262446b09db..2dfd025bd4dd 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -649,24 +649,24 @@ type Vector
                 prefix + this.unsafe_at 0 + (1.up_to this.length . fold "" acc-> i-> acc + separator + this.unsafe_at i) + suffix
 
     ## Creates a new vector with the skipping elements until `start` and then
-       continuing for `length` elements.
+       continuing until `end` index.
 
        Arguments:
-       - start: The number of elements to drop from the start of `this`.
-       - length: The number of elements for the sub-vector.
+       - start: The index of the first element to include.
+       - end: The index to stop slicing at.
 
        > Example
-         Remove the first 2 elements then take 5 from the vector.
-
-             [1, 2, 3, 4, 5, 6, 7, 8].slice 2 5
-    slice : Integer -> Integer -> Vector Any
-    slice start length =
-        if start > this.length then Vector (Array.new 0) else
-            slice_length = Math.min (this.length - start) length
-            if slice_length == 0 then Vector (Array.new 0) else
-                new_array = Array.new slice_length
-                Array.Copy this.to_array start new_array 0 slice_length
-                Vector new_array
+         Remove the first 2 elements then continue until index 5 from the vector.
+
+             [1, 2, 3, 4, 5, 6, 7, 8].slice 2 5 == [3, 4, 5]
+    take : Integer -> Integer -> Vector Any
+    take start end =
+        slice_start = Math.max 0 start
+        slice_end = Math.min this.length end
+        if slice_start >= slice_end then Vector (Array.new 0) else
+            new_array = Array.new (slice_end - slice_start)
+            Array.Copy this.to_array start new_array 0 new_array.length
+            Vector new_array
 
     ## Creates a new vector with the first `count` elements in `this` removed.
 
@@ -678,7 +678,7 @@ type Vector
 
              [1, 2, 3, 4, 5].drop_start 1
     drop_start : Integer -> Vector Any
-    drop_start count = this.slice count (this.length - count)
+    drop_start count = this.take count this.length
 
     ## Creates a new vector with the last `count` elements in `this` removed.
 
@@ -690,7 +690,7 @@ type Vector
 
              [1, 2, 3, 4, 5].drop_end 2
     drop_end : Integer -> Vector Any
-    drop_end count = this.slice 0 (this.length - count)
+    drop_end count = this.take 0 (this.length - count)
 
     ## Creates a new vector, consisting of the first `count` elements on the
        left of `this`.
@@ -703,7 +703,7 @@ type Vector
 
              [1, 2, 3, 4, 5].take_start 2
     take_start : Integer -> Vector Any
-    take_start count = this.slice 0 count
+    take_start count = this.take 0 count
 
     ## Creates a new vector, consisting of the last `count` elements on the
        right of `this`.
@@ -716,7 +716,7 @@ type Vector
 
              [1, 2, 3, 4, 5].take_end 3
     take_end : Integer -> Vector Any
-    take_end count = this.slice (this.length - count) count
+    take_end count = this.take (this.length - count) this.length
 
     ## Performs a pair-wise operation passed in `function` on consecutive
        elements of `this` and `that`.
diff --git a/test/Tests/src/Data/Vector_Spec.enso b/test/Tests/src/Data/Vector_Spec.enso
index b6f3098298bc..208114ef8aaf 100644
--- a/test/Tests/src/Data/Vector_Spec.enso
+++ b/test/Tests/src/Data/Vector_Spec.enso
@@ -185,6 +185,7 @@ spec = Test.group "Vectors" <|
         vec = [1, 2, 3, 4, 5, 6]
         first_four = [1, 2, 3, 4]
         last_four = [3, 4, 5, 6]
+        vec.take 2 4 . should_equal [3, 4]
         vec.drop_start 2 . should_equal last_four
         vec.drop_end 2 . should_equal first_four
         vec.take_start 4 . should_equal first_four

From 3b168f67e14cbb7ed6abeff60f6c948394c93558 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Thu, 27 Jan 2022 22:14:07 +0000
Subject: [PATCH 06/20] ChangeLog

---
 CHANGELOG.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 971cc9043179..18b395b03300 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -60,6 +60,8 @@
 - [Implemented initial `Table.group_by` function on Standard.Table][3305]
 - [Implemented `Text.pad` and `Text.trim`][3309]
 - [Updated `Text.repeat` and added `*` operator shorthand][3310]
+- [General improved Vector performance and new `Vector.each_with_index`,
+  `Vector.fold_with_index` and `Vector.take` methods.][3236]
 
 [debug-shortcuts]:
   https://github.com/enso-org/enso/blob/develop/app/gui/docs/product/shortcuts.md#debug
@@ -94,6 +96,7 @@
 [3305]: https://github.com/enso-org/enso/pull/3305
 [3309]: https://github.com/enso-org/enso/pull/3309
 [3310]: https://github.com/enso-org/enso/pull/3310
+[3236]: https://github.com/enso-org/enso/pull/3236
 
 #### Enso Compiler
 

From 0b07c14d0187343a31bc0e84e2a4e2d6f545b156 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Mon, 31 Jan 2022 11:20:55 +0000
Subject: [PATCH 07/20] Clone node experiment

---
 .../Base/0.0.0-dev/src/Data/Vector.enso       |  17 +-
 .../expression/builtin/mutable/CloneNode.java | 154 ++++++++++++++++++
 .../interpreter/runtime/builtin/Mutable.java  |   1 +
 .../runtime/src/main/resources/Builtins.enso  |  13 ++
 test/Tests/src/Data/Vector_Spec.enso          |   3 +
 test/Tests/src/System/File_Spec.enso          |   2 +
 6 files changed, 179 insertions(+), 11 deletions(-)
 create mode 100644 engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CloneNode.java

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 2dfd025bd4dd..6cbcbd58adf6 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -601,8 +601,7 @@ type Vector
     + : Vector Any -> Vector Any
     + that =
         this_len = this.length
-        arr = Array.new (this_len + that.length)
-        Array.copy this.to_array 0 arr 0 this_len
+        arr = Array.clone this.to_array 0 this_len (this_len + that.length)
         Array.copy that.to_array 0 arr this_len that.length
         Vector arr
 
@@ -664,8 +663,8 @@ type Vector
         slice_start = Math.max 0 start
         slice_end = Math.min this.length end
         if slice_start >= slice_end then Vector (Array.new 0) else
-            new_array = Array.new (slice_end - slice_start)
-            Array.Copy this.to_array start new_array 0 new_array.length
+            len = slice_end - slice_start
+            new_array = Array.clone this.to_array slice_start len len
             Vector new_array
 
     ## Creates a new vector with the first `count` elements in `this` removed.
@@ -894,8 +893,7 @@ type Vector
         ## Prepare the destination array that will underlie the vector. We do
            not want to sort in place on the original vector, as `sort` is not
            intended to be mutable.
-        new_vec_arr = Array.new this.length
-        Array.copy this.to_array 0 new_vec_arr 0 this.length
+        new_vec_arr = Array.clone this.to_array 0 this.length this.length
 
         ## As we want to account for both custom projections and custom
            comparisons we need to construct a comparator for internal use that
@@ -1070,8 +1068,7 @@ type Builder
             Unsafe.set_atom_field this 1 (this.length + 1)
         False ->
             old_array = this.to_array
-            new_array = Array.new old_array.length*2
-            Array.copy old_array 0 new_array 0 old_array.length
+            new_array = Array.clone this.to_array 0 old_array.length old_array.length*2
             Unsafe.set_atom_field this 0 new_array
             this.append item
             Nothing
@@ -1099,9 +1096,7 @@ type Builder
                 bldr.to_vector
     to_vector : Vector Any
     to_vector =
-        old_array = this.to_array
-        new_array = Array.new this.length
-        Array.copy old_array 0 new_array 0 this.length
+        new_array = Array.clone this.to_array 0 this.length this.length
         Vector new_array
 
 ## UNSTABLE
diff --git a/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CloneNode.java b/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CloneNode.java
new file mode 100644
index 000000000000..f25567ed2866
--- /dev/null
+++ b/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CloneNode.java
@@ -0,0 +1,154 @@
+package org.enso.interpreter.node.expression.builtin.mutable;
+
+import com.oracle.truffle.api.dsl.CachedContext;
+import com.oracle.truffle.api.dsl.Fallback;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.InvalidArrayIndexException;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.Language;
+import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.runtime.Context;
+import org.enso.interpreter.runtime.builtin.Builtins;
+import org.enso.interpreter.runtime.data.Array;
+import org.enso.interpreter.runtime.error.PanicException;
+
+@BuiltinMethod(type = "Array", name = "clone", description = "Copies one array to another.")
+public abstract class CloneNode extends Node {
+
+    static CloneNode build() {
+        return CloneNodeGen.create();
+    }
+
+    abstract Object execute(
+        Object _this, Object src, long source_index, long source_count, long new_size);
+
+    @Specialization
+    Object doArray(
+            Object _this,
+            Array src,
+            long source_index,
+            long source_count,
+            long new_size,
+            @CachedContext(Language.class) Context ctx) {
+        Array output = new Array(new_size);
+        System.arraycopy(
+                src.getItems(), (int) source_index, output.getItems(), 0, (int) source_count);
+        return output;
+    }
+
+    @Specialization
+    Object doPolyglotArray(
+            Object _this,
+            byte[] src,
+            long source_index,
+            long source_count,
+            long new_size,
+            @CachedContext(Language.class) Context ctx) {
+        byte[] output = new byte[(int) new_size];
+        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
+        return output;
+    }
+
+    @Specialization
+    Object doPolyglotArray(
+            Object _this,
+            int[] src,
+            long source_index,
+            long source_count,
+            long new_size,
+            @CachedContext(Language.class) Context ctx) {
+        int[] output = new int[(int) new_size];
+        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
+        return output;
+    }
+
+    @Specialization
+    Object doPolyglotArray(
+            Object _this,
+            long[] src,
+            long source_index,
+            long source_count,
+            long new_size,
+            @CachedContext(Language.class) Context ctx) {
+        long[] output = new long[(int) new_size];
+        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
+        return output;
+    }
+
+    @Specialization
+    Object doPolyglotArray(
+            Object _this,
+            char[] src,
+            long source_index,
+            long source_count,
+            long new_size,
+            @CachedContext(Language.class) Context ctx) {
+        char[] output = new char[(int) new_size];
+        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
+        return output;
+    }
+
+    @Specialization
+    Object doPolyglotArray(
+            Object _this,
+            float[] src,
+            long source_index,
+            long source_count,
+            long new_size,
+            @CachedContext(Language.class) Context ctx) {
+        float[] output = new float[(int) new_size];
+        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
+        return output;
+    }
+
+    @Specialization
+    Object doPolyglotArray(
+            Object _this,
+            double[] src,
+            long source_index,
+            long new_size,
+            long source_count,
+            @CachedContext(Language.class) Context ctx) {
+        double[] output = new double[(int) new_size];
+        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
+        return output;
+    }
+
+    @Specialization(guards = "arrays.hasArrayElements(src)")
+    Object doPolyglotArray(
+            Object _this,
+            Object src,
+            long source_index,
+            long new_size,
+            long source_count,
+            @CachedLibrary(limit = "3") InteropLibrary arrays,
+            @CachedContext(Language.class) Context ctx) {
+        Array dest = new Array(new_size);
+        try {
+            for (int i = 0; i < source_count; i++) {
+                dest.getItems()[i] = arrays.readArrayElement(src, source_index + i);
+            }
+        } catch (UnsupportedMessageException e) {
+            throw new IllegalStateException("Unreachable");
+        } catch (InvalidArrayIndexException e) {
+            throw new PanicException(
+                    ctx.getBuiltins().error().makeInvalidArrayIndexError(src, e.getInvalidIndex()), this);
+        }
+        return dest;
+    }
+
+    @Fallback
+    Object doOther(
+            Object _this,
+            Object src,
+            long source_index,
+            long source_count,
+            long new_size) {
+        Builtins builtins = lookupContextReference(Language.class).get().getBuiltins();
+        throw new PanicException(
+                builtins.error().makeTypeError(builtins.mutable().array().newInstance(), src, "src"), this);
+    }
+}
\ No newline at end of file
diff --git a/engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Mutable.java b/engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Mutable.java
index 3e055e01e228..a7ab5cd8c581 100644
--- a/engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Mutable.java
+++ b/engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Mutable.java
@@ -30,6 +30,7 @@ public Mutable(Language language, ModuleScope scope) {
     scope.registerMethod(array, "at", GetAtMethodGen.makeFunction(language));
     scope.registerMethod(array, "set_at", SetAtMethodGen.makeFunction(language));
     scope.registerMethod(array, "copy", CopyMethodGen.makeFunction(language));
+    scope.registerMethod(array, "clone", CloneMethodGen.makeFunction(language));
     scope.registerMethod(array, "sort", SortMethodGen.makeFunction(language));
 
     ref = new AtomConstructor("Ref", scope).initializeFields();
diff --git a/engine/runtime/src/main/resources/Builtins.enso b/engine/runtime/src/main/resources/Builtins.enso
index 8f2bfcfa5916..92aaf9390d34 100644
--- a/engine/runtime/src/main/resources/Builtins.enso
+++ b/engine/runtime/src/main/resources/Builtins.enso
@@ -906,6 +906,19 @@ type Array
     copy src source_index dest dest_index count =
         @Builtin_Method "Array.copy"
 
+    ## Clones from the source array, beginning at the specified position, to
+       a new destination array.
+
+       Arguments:
+       - src: The source array.
+       - source_index: The start position in the src array.
+       - source_count: Amount to copy from source.
+       - new_size: Size of new array.
+
+    clone : Array -> Integer -> Integer -> Integer -> Array
+    clone src source_index source_count new_size =
+        @Builtin_Method "Array.clone"
+
     ## Gets the element at index in the array this.
 
        Arguments:
diff --git a/test/Tests/src/Data/Vector_Spec.enso b/test/Tests/src/Data/Vector_Spec.enso
index 208114ef8aaf..402e4d0451de 100644
--- a/test/Tests/src/Data/Vector_Spec.enso
+++ b/test/Tests/src/Data/Vector_Spec.enso
@@ -27,6 +27,9 @@ foreign js generate_js_array = """
 
 spec = Test.group "Vectors" <|
 
+    Test.specify "text bytes" <|
+        "Lore".utf_8 . should_equal [76, 111, 114, 101]
+
     Test.specify "should allow vector creation with a programmatic constructor" <|
         Vector.new 100 (ix -> ix + 1) . fold 0 (+) . should_equal 5050
 
diff --git a/test/Tests/src/System/File_Spec.enso b/test/Tests/src/System/File_Spec.enso
index 1ce2fb9c8a32..85d3fd12355b 100644
--- a/test/Tests/src/System/File_Spec.enso
+++ b/test/Tests/src/System/File_Spec.enso
@@ -21,6 +21,7 @@ spec =
 
         Test.specify "should allow reading a file to byte vector" <|
             contents = sample_file.read_bytes
+            IO.println (Meta.get_qualified_type_name contents.to_array)
             contents.take_start 6 . should_equal [67, 117, 112, 99, 97, 107]
 
         Test.specify "should handle exceptions when reading a non-existent file" <|
@@ -109,3 +110,4 @@ spec =
             filtered2 = Enso_Project.data.list name_filter="*/*/*" recursive=True . map .to_text
             filtered2.should_equal (resolve ["subdirectory/nested/b.txt"])
 
+main = Test.Suite.run_main here.spec

From 1e68f867221207254291f2ad82518aaa11c70782 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 2 Mar 2022 08:44:19 +0000
Subject: [PATCH 08/20] Remove Clone idea Revert + and take to use iterative
 approach for now

---
 .../Base/0.0.0-dev/src/Data/Vector.enso       |  19 ++-
 .../expression/builtin/mutable/CloneNode.java | 154 ------------------
 .../interpreter/runtime/builtin/Mutable.java  |   1 -
 .../runtime/src/main/resources/Builtins.enso  |  13 --
 4 files changed, 13 insertions(+), 174 deletions(-)
 delete mode 100644 engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CloneNode.java

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 6cbcbd58adf6..01a9f2087815 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -601,8 +601,11 @@ type Vector
     + : Vector Any -> Vector Any
     + that =
         this_len = this.length
-        arr = Array.clone this.to_array 0 this_len (this_len + that.length)
-        Array.copy that.to_array 0 arr this_len that.length
+        arr = Array.new (this_len + that.length)
+        0.up_to this_len . each i->
+            arr.set_at i (this.unsafe_at i)
+        this.length.up_to arr.length . each i->
+            arr.set_at i (that.unsafe_at i-this_len)
         Vector arr
 
     ## Add `element` to the beginning of `this` vector.
@@ -664,7 +667,7 @@ type Vector
         slice_end = Math.min this.length end
         if slice_start >= slice_end then Vector (Array.new 0) else
             len = slice_end - slice_start
-            new_array = Array.clone this.to_array slice_start len len
+            here.new len (i -> this.unsafe_at (i+slice_start))
             Vector new_array
 
     ## Creates a new vector with the first `count` elements in `this` removed.
@@ -893,7 +896,8 @@ type Vector
         ## Prepare the destination array that will underlie the vector. We do
            not want to sort in place on the original vector, as `sort` is not
            intended to be mutable.
-        new_vec_arr = Array.clone this.to_array 0 this.length this.length
+        new_vec_arr = Array.new this.length
+        Array.copy this.to_array 0 new_vec_arr 0 this.length
 
         ## As we want to account for both custom projections and custom
            comparisons we need to construct a comparator for internal use that
@@ -1068,7 +1072,8 @@ type Builder
             Unsafe.set_atom_field this 1 (this.length + 1)
         False ->
             old_array = this.to_array
-            new_array = Array.clone this.to_array 0 old_array.length old_array.length*2
+            new_array = Array.new old_array.length*2
+            Array.copy old_arrays 0 new_array 0 old_array.length
             Unsafe.set_atom_field this 0 new_array
             this.append item
             Nothing
@@ -1096,7 +1101,9 @@ type Builder
                 bldr.to_vector
     to_vector : Vector Any
     to_vector =
-        new_array = Array.clone this.to_array 0 this.length this.length
+        old_array = this.to_array
+        new_array = Array.new this.length
+        Array.copy old_arrays 0 new_array 0 this.length
         Vector new_array
 
 ## UNSTABLE
diff --git a/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CloneNode.java b/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CloneNode.java
deleted file mode 100644
index f25567ed2866..000000000000
--- a/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CloneNode.java
+++ /dev/null
@@ -1,154 +0,0 @@
-package org.enso.interpreter.node.expression.builtin.mutable;
-
-import com.oracle.truffle.api.dsl.CachedContext;
-import com.oracle.truffle.api.dsl.Fallback;
-import com.oracle.truffle.api.dsl.Specialization;
-import com.oracle.truffle.api.interop.InteropLibrary;
-import com.oracle.truffle.api.interop.InvalidArrayIndexException;
-import com.oracle.truffle.api.interop.UnsupportedMessageException;
-import com.oracle.truffle.api.library.CachedLibrary;
-import com.oracle.truffle.api.nodes.Node;
-import org.enso.interpreter.Language;
-import org.enso.interpreter.dsl.BuiltinMethod;
-import org.enso.interpreter.runtime.Context;
-import org.enso.interpreter.runtime.builtin.Builtins;
-import org.enso.interpreter.runtime.data.Array;
-import org.enso.interpreter.runtime.error.PanicException;
-
-@BuiltinMethod(type = "Array", name = "clone", description = "Copies one array to another.")
-public abstract class CloneNode extends Node {
-
-    static CloneNode build() {
-        return CloneNodeGen.create();
-    }
-
-    abstract Object execute(
-        Object _this, Object src, long source_index, long source_count, long new_size);
-
-    @Specialization
-    Object doArray(
-            Object _this,
-            Array src,
-            long source_index,
-            long source_count,
-            long new_size,
-            @CachedContext(Language.class) Context ctx) {
-        Array output = new Array(new_size);
-        System.arraycopy(
-                src.getItems(), (int) source_index, output.getItems(), 0, (int) source_count);
-        return output;
-    }
-
-    @Specialization
-    Object doPolyglotArray(
-            Object _this,
-            byte[] src,
-            long source_index,
-            long source_count,
-            long new_size,
-            @CachedContext(Language.class) Context ctx) {
-        byte[] output = new byte[(int) new_size];
-        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
-        return output;
-    }
-
-    @Specialization
-    Object doPolyglotArray(
-            Object _this,
-            int[] src,
-            long source_index,
-            long source_count,
-            long new_size,
-            @CachedContext(Language.class) Context ctx) {
-        int[] output = new int[(int) new_size];
-        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
-        return output;
-    }
-
-    @Specialization
-    Object doPolyglotArray(
-            Object _this,
-            long[] src,
-            long source_index,
-            long source_count,
-            long new_size,
-            @CachedContext(Language.class) Context ctx) {
-        long[] output = new long[(int) new_size];
-        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
-        return output;
-    }
-
-    @Specialization
-    Object doPolyglotArray(
-            Object _this,
-            char[] src,
-            long source_index,
-            long source_count,
-            long new_size,
-            @CachedContext(Language.class) Context ctx) {
-        char[] output = new char[(int) new_size];
-        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
-        return output;
-    }
-
-    @Specialization
-    Object doPolyglotArray(
-            Object _this,
-            float[] src,
-            long source_index,
-            long source_count,
-            long new_size,
-            @CachedContext(Language.class) Context ctx) {
-        float[] output = new float[(int) new_size];
-        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
-        return output;
-    }
-
-    @Specialization
-    Object doPolyglotArray(
-            Object _this,
-            double[] src,
-            long source_index,
-            long new_size,
-            long source_count,
-            @CachedContext(Language.class) Context ctx) {
-        double[] output = new double[(int) new_size];
-        System.arraycopy(src, (int) source_index, output, 0, (int) source_count);
-        return output;
-    }
-
-    @Specialization(guards = "arrays.hasArrayElements(src)")
-    Object doPolyglotArray(
-            Object _this,
-            Object src,
-            long source_index,
-            long new_size,
-            long source_count,
-            @CachedLibrary(limit = "3") InteropLibrary arrays,
-            @CachedContext(Language.class) Context ctx) {
-        Array dest = new Array(new_size);
-        try {
-            for (int i = 0; i < source_count; i++) {
-                dest.getItems()[i] = arrays.readArrayElement(src, source_index + i);
-            }
-        } catch (UnsupportedMessageException e) {
-            throw new IllegalStateException("Unreachable");
-        } catch (InvalidArrayIndexException e) {
-            throw new PanicException(
-                    ctx.getBuiltins().error().makeInvalidArrayIndexError(src, e.getInvalidIndex()), this);
-        }
-        return dest;
-    }
-
-    @Fallback
-    Object doOther(
-            Object _this,
-            Object src,
-            long source_index,
-            long source_count,
-            long new_size) {
-        Builtins builtins = lookupContextReference(Language.class).get().getBuiltins();
-        throw new PanicException(
-                builtins.error().makeTypeError(builtins.mutable().array().newInstance(), src, "src"), this);
-    }
-}
\ No newline at end of file
diff --git a/engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Mutable.java b/engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Mutable.java
index a7ab5cd8c581..3e055e01e228 100644
--- a/engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Mutable.java
+++ b/engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Mutable.java
@@ -30,7 +30,6 @@ public Mutable(Language language, ModuleScope scope) {
     scope.registerMethod(array, "at", GetAtMethodGen.makeFunction(language));
     scope.registerMethod(array, "set_at", SetAtMethodGen.makeFunction(language));
     scope.registerMethod(array, "copy", CopyMethodGen.makeFunction(language));
-    scope.registerMethod(array, "clone", CloneMethodGen.makeFunction(language));
     scope.registerMethod(array, "sort", SortMethodGen.makeFunction(language));
 
     ref = new AtomConstructor("Ref", scope).initializeFields();
diff --git a/engine/runtime/src/main/resources/Builtins.enso b/engine/runtime/src/main/resources/Builtins.enso
index 92aaf9390d34..8f2bfcfa5916 100644
--- a/engine/runtime/src/main/resources/Builtins.enso
+++ b/engine/runtime/src/main/resources/Builtins.enso
@@ -906,19 +906,6 @@ type Array
     copy src source_index dest dest_index count =
         @Builtin_Method "Array.copy"
 
-    ## Clones from the source array, beginning at the specified position, to
-       a new destination array.
-
-       Arguments:
-       - src: The source array.
-       - source_index: The start position in the src array.
-       - source_count: Amount to copy from source.
-       - new_size: Size of new array.
-
-    clone : Array -> Integer -> Integer -> Integer -> Array
-    clone src source_index source_count new_size =
-        @Builtin_Method "Array.clone"
-
     ## Gets the element at index in the array this.
 
        Arguments:

From c992991383b8e09f9b210b0eda54f3d8b8ef47ad Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 2 Mar 2022 10:43:37 +0000
Subject: [PATCH 09/20] Fix issues

---
 .../lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso         | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 01a9f2087815..33011d001737 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -668,7 +668,6 @@ type Vector
         if slice_start >= slice_end then Vector (Array.new 0) else
             len = slice_end - slice_start
             here.new len (i -> this.unsafe_at (i+slice_start))
-            Vector new_array
 
     ## Creates a new vector with the first `count` elements in `this` removed.
 
@@ -1073,7 +1072,7 @@ type Builder
         False ->
             old_array = this.to_array
             new_array = Array.new old_array.length*2
-            Array.copy old_arrays 0 new_array 0 old_array.length
+            Array.copy old_array 0 new_array 0 old_array.length
             Unsafe.set_atom_field this 0 new_array
             this.append item
             Nothing
@@ -1103,7 +1102,7 @@ type Builder
     to_vector =
         old_array = this.to_array
         new_array = Array.new this.length
-        Array.copy old_arrays 0 new_array 0 this.length
+        Array.copy old_array 0 new_array 0 this.length
         Vector new_array
 
 ## UNSTABLE

From 062fa4f134cf4696f7549f35438a01252395dcad Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 2 Mar 2022 12:28:55 +0000
Subject: [PATCH 10/20] Workaround polyglot issue

---
 .../Base/0.0.0-dev/src/Data/Vector.enso       | 22 +++++++++++++------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 33011d001737..c5cdcb4429e1 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -588,6 +588,13 @@ type Vector
         eq_at i = this.unsafe_at i == that.unsafe_at i
         if this.length == that.length then 0.up_to this.length . all eq_at else False
 
+    ## Copy the backing Array to an Enso Array
+    copy_array : Array
+    copy_array start_index dest_array dest_start length =
+        case Builtins.Meta.is_polyglot this.to_array of
+            True -> 0.up_to length . each i->(dest_array.set_at (i+dest_start) (this.to_array.at i+start_index))
+            False -> Array.copy this.to_array start_index dest_array dest_start length
+
     ## Concatenates two vectors, resulting in a new vector, containing all the
        elements of `this`, followed by all the elements of `that`.
 
@@ -602,10 +609,8 @@ type Vector
     + that =
         this_len = this.length
         arr = Array.new (this_len + that.length)
-        0.up_to this_len . each i->
-            arr.set_at i (this.unsafe_at i)
-        this.length.up_to arr.length . each i->
-            arr.set_at i (that.unsafe_at i-this_len)
+        this.copy_array 0 arr 0 this_len
+        that.copy_array 0 arr this_len that.length
         Vector arr
 
     ## Add `element` to the beginning of `this` vector.
@@ -666,8 +671,11 @@ type Vector
         slice_start = Math.max 0 start
         slice_end = Math.min this.length end
         if slice_start >= slice_end then Vector (Array.new 0) else
-            len = slice_end - slice_start
-            here.new len (i -> this.unsafe_at (i+slice_start))
+            if (slice_start == 0) && (slice_end == this.length) then this else
+                len = slice_end - slice_start
+                arr = Array.new len
+                this.copy_array slice_start arr 0 len
+                Vector arr
 
     ## Creates a new vector with the first `count` elements in `this` removed.
 
@@ -896,7 +904,7 @@ type Vector
            not want to sort in place on the original vector, as `sort` is not
            intended to be mutable.
         new_vec_arr = Array.new this.length
-        Array.copy this.to_array 0 new_vec_arr 0 this.length
+        this.copy_array 0 new_vec_arr 0 this.length
 
         ## As we want to account for both custom projections and custom
            comparisons we need to construct a comparator for internal use that

From cfdc960df6f58fc0b36af1260a63fa2c923c8f38 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 2 Mar 2022 15:00:22 +0000
Subject: [PATCH 11/20] Add test for sorting a polyglot array

---
 test/Tests/src/Data/Vector_Spec.enso | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/test/Tests/src/Data/Vector_Spec.enso b/test/Tests/src/Data/Vector_Spec.enso
index 402e4d0451de..499e4326c1af 100644
--- a/test/Tests/src/Data/Vector_Spec.enso
+++ b/test/Tests/src/Data/Vector_Spec.enso
@@ -345,4 +345,9 @@ spec = Test.group "Vectors" <|
     Test.specify "should return a vector containing only unique elements up to some criteria" <|
         [Pair 1 "a", Pair 2 "b", Pair 1 "c"] . distinct (on = _.first) . should_equal [Pair 1 "a", Pair 2 "b"]
 
+    Test.specify "should be able to sort a polyglot vector" <|
+        input = "beta".utf_8
+        expected = "abet".utf_8
+        input.sort . should_equal expected
+
 main = Test.Suite.run_main here.spec

From 4a573d052bc17ffd55454b0e6242056d803b4a5d Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 2 Mar 2022 16:22:39 +0000
Subject: [PATCH 12/20] Add test for sorting a polyglot array

---
 .../lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso      | 8 +++++---
 test/Tests/src/Data/Vector_Spec.enso                      | 1 +
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index c5cdcb4429e1..0e2597cee70f 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -470,8 +470,7 @@ type Vector
         length = this.fold 0 acc-> elem-> acc + elem.length
         arr = Array.new length
         this.fold 0 i-> vec->
-            # TODO could use Array.copy here, if it was safe...
-            vec.map_with_index j-> elem-> arr.set_at i+j elem
+            vec.copy_array 0 arr i vec.length
             i + vec.length
         Vector arr
 
@@ -588,7 +587,10 @@ type Vector
         eq_at i = this.unsafe_at i == that.unsafe_at i
         if this.length == that.length then 0.up_to this.length . all eq_at else False
 
-    ## Copy the backing Array to an Enso Array
+    ## PRIVATE
+       Copy the backing Array to an Enso Array
+       TODO This is a workaround for the issue with polyglot Array.copy
+            https://www.pivotaltracker.com/story/show/181122542
     copy_array : Array
     copy_array start_index dest_array dest_start length =
         case Builtins.Meta.is_polyglot this.to_array of
diff --git a/test/Tests/src/Data/Vector_Spec.enso b/test/Tests/src/Data/Vector_Spec.enso
index 499e4326c1af..3b49200e20b7 100644
--- a/test/Tests/src/Data/Vector_Spec.enso
+++ b/test/Tests/src/Data/Vector_Spec.enso
@@ -148,6 +148,7 @@ spec = Test.group "Vectors" <|
         [[1]].flatten . should_equal [1]
         [[[1], [2, 3]], [[4]]].flatten . should_equal [[1], [2, 3], [4]]
         [["a", 2], [], [[[3]]], [T 1 2, 44]].flatten . should_equal ["a", 2, [[3]], T 1 2, 44]
+        (["polyglot", " ", "array"].map .utf_8).flatten . should_equal "polyglot array".utf_8
 
     Test.specify "should allow applying a function to each element" <|
         vec = [1, 2, 3, 4]

From 7720904bd59dc3e507d63fc4727906d8610ce012 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 2 Mar 2022 16:25:24 +0000
Subject: [PATCH 13/20] Revert debugging change

---
 test/Tests/src/System/File_Spec.enso | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/test/Tests/src/System/File_Spec.enso b/test/Tests/src/System/File_Spec.enso
index 85d3fd12355b..93e652a719f6 100644
--- a/test/Tests/src/System/File_Spec.enso
+++ b/test/Tests/src/System/File_Spec.enso
@@ -21,7 +21,6 @@ spec =
 
         Test.specify "should allow reading a file to byte vector" <|
             contents = sample_file.read_bytes
-            IO.println (Meta.get_qualified_type_name contents.to_array)
             contents.take_start 6 . should_equal [67, 117, 112, 99, 97, 107]
 
         Test.specify "should handle exceptions when reading a non-existent file" <|
@@ -109,5 +108,3 @@ spec =
 
             filtered2 = Enso_Project.data.list name_filter="*/*/*" recursive=True . map .to_text
             filtered2.should_equal (resolve ["subdirectory/nested/b.txt"])
-
-main = Test.Suite.run_main here.spec

From 5c01bf645b383c8c2df2117ffb42c3c3439282d5 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Wed, 2 Mar 2022 16:57:13 +0000
Subject: [PATCH 14/20] Change flat_map to use flatten

---
 .../lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso      | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 0e2597cee70f..a19375ff94ec 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -450,13 +450,7 @@ type Vector
             [0, 1, 2] . flat_map (n -> Vector.fill n n)
     flat_map : (Any -> Vector Any) -> Vector Any
     flat_map function =
-        mapped = this.map function
-        length = mapped.fold 0 acc-> elem-> acc + elem.length
-        arr = Array.new length
-        mapped.fold 0 i-> vec->
-            vec.map_with_index j-> elem-> arr.set_at i+j elem
-            i + vec.length
-        Vector arr
+        this.map function . flatten
 
     ## Transforms a vector of vectors into a vector of inner elements - removes
        one layer of nesting from a stack of nested vectors.

From c1eae124563dab69d6451dee3f6d3372c0cbf8e2 Mon Sep 17 00:00:00 2001
From: James Dunkerley <jdunkerley@users.noreply.github.com>
Date: Wed, 2 Mar 2022 17:03:17 +0000
Subject: [PATCH 15/20] Update
 distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Radosław Waśko <radoslaw.wasko@enso.org>
---
 distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index a19375ff94ec..4a268de9dde5 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -386,7 +386,7 @@ type Vector
          Splitting a vector into even and odd elements.
 
              [1, 2, 3, 4, 5].partition (x -> x % 2 == 0) == (Pair [2, 4] [1, 3, 5])
-    partition : (Any -> Boolean) -> Pair Vector Any Vector Any
+    partition : (Any -> Boolean) -> Pair (Vector Any) (Vector Any)
     partition predicate =
         pair = this.fold (Pair here.new_builder here.new_builder) acc-> elem->
             case predicate elem of

From 83661f1c57a334c6032582dd53715c9e5ff64b0c Mon Sep 17 00:00:00 2001
From: James Dunkerley <jdunkerley@users.noreply.github.com>
Date: Wed, 2 Mar 2022 17:03:25 +0000
Subject: [PATCH 16/20] Update
 distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Radosław Waśko <radoslaw.wasko@enso.org>
---
 distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 4a268de9dde5..74cf77c023b7 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -414,7 +414,7 @@ type Vector
          Splitting a vector into elements at even and odd positions.
 
              ["a", "b", "c", "d"].partition_with_index (ix -> _ -> ix % 2 == 0) == (Pair ["a", "c"] ["b", "d"])
-    partition_with_index : (Integer -> Any -> Boolean) -> Pair Vector Any Vector Any
+    partition_with_index : (Integer -> Any -> Boolean) -> Pair (Vector Any) (Vector Any)
     partition_with_index predicate =
         pair = this.fold_with_index (Pair here.new_builder here.new_builder) acc-> ix-> elem->
             case predicate ix elem of

From b2a3b0d410ce4619fe126a7e9a41345a7a619dce Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Thu, 3 Mar 2022 10:34:10 +0000
Subject: [PATCH 17/20] Move to static method

---
 .../0.0.0-dev/src/Data/Array/Extensions.enso  | 10 ++++++++++
 .../Base/0.0.0-dev/src/Data/Vector.enso       | 20 +++++--------------
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
index 3dfeeb48b9ab..e1bb1f95a6bc 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
@@ -1,4 +1,5 @@
 from Standard.Base import all
+from Standard.Builtins import Builtins
 
 ## UNSTABLE
    ADVANCED
@@ -17,3 +18,12 @@ Array.to_default_visualization_data : Text
 Array.to_default_visualization_data =
     Vector.Vector this . to_default_visualization_data
 
+## PRIVATE
+   Copy the backing Array to an Enso Array
+   TODO This is a workaround for the issue with polyglot Array.copy
+        https://www.pivotaltracker.com/story/show/181122542
+Array.copy_to : Array->Integer->Array->Integer->Integer
+Array.copy_to src_array src_start dest_array dest_start length =
+    case Builtins.Meta.is_polyglot src_array of
+        True -> 0.up_to length . each i->(dest_array.set_at (i+dest_start) (src_array.at i+src_start))
+        False -> Array.copy src_array src_start dest_array dest_start length
diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 74cf77c023b7..86e8e6fe7b8d 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -464,7 +464,7 @@ type Vector
         length = this.fold 0 acc-> elem-> acc + elem.length
         arr = Array.new length
         this.fold 0 i-> vec->
-            vec.copy_array 0 arr i vec.length
+            Array.copy_to vec.to_array 0 arr i vec.length
             i + vec.length
         Vector arr
 
@@ -581,16 +581,6 @@ type Vector
         eq_at i = this.unsafe_at i == that.unsafe_at i
         if this.length == that.length then 0.up_to this.length . all eq_at else False
 
-    ## PRIVATE
-       Copy the backing Array to an Enso Array
-       TODO This is a workaround for the issue with polyglot Array.copy
-            https://www.pivotaltracker.com/story/show/181122542
-    copy_array : Array
-    copy_array start_index dest_array dest_start length =
-        case Builtins.Meta.is_polyglot this.to_array of
-            True -> 0.up_to length . each i->(dest_array.set_at (i+dest_start) (this.to_array.at i+start_index))
-            False -> Array.copy this.to_array start_index dest_array dest_start length
-
     ## Concatenates two vectors, resulting in a new vector, containing all the
        elements of `this`, followed by all the elements of `that`.
 
@@ -605,8 +595,8 @@ type Vector
     + that =
         this_len = this.length
         arr = Array.new (this_len + that.length)
-        this.copy_array 0 arr 0 this_len
-        that.copy_array 0 arr this_len that.length
+        Array.copy_to this.to_array 0 arr 0 this_len
+        Array.copy_to that.to_array 0 arr this_len that.length
         Vector arr
 
     ## Add `element` to the beginning of `this` vector.
@@ -670,7 +660,7 @@ type Vector
             if (slice_start == 0) && (slice_end == this.length) then this else
                 len = slice_end - slice_start
                 arr = Array.new len
-                this.copy_array slice_start arr 0 len
+                Array.copy_to this.to_array slice_start arr 0 len
                 Vector arr
 
     ## Creates a new vector with the first `count` elements in `this` removed.
@@ -900,7 +890,7 @@ type Vector
            not want to sort in place on the original vector, as `sort` is not
            intended to be mutable.
         new_vec_arr = Array.new this.length
-        this.copy_array 0 new_vec_arr 0 this.length
+        Array.copy_to this.to_array 0 new_vec_arr 0 this.length
 
         ## As we want to account for both custom projections and custom
            comparisons we need to construct a comparator for internal use that

From 14d656a147f883b482b248f7f6ae78dd0175b3c1 Mon Sep 17 00:00:00 2001
From: James Dunkerley <james.dunkerley@enso.org>
Date: Thu, 3 Mar 2022 12:57:10 +0000
Subject: [PATCH 18/20] Fix Array.Copy

---
 .../Base/0.0.0-dev/src/Data/Array/Extensions.enso   | 10 ----------
 .../Standard/Base/0.0.0-dev/src/Data/Vector.enso    | 10 +++++-----
 .../node/expression/builtin/mutable/CopyNode.java   | 13 ++++++++-----
 3 files changed, 13 insertions(+), 20 deletions(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
index e1bb1f95a6bc..c22476f3788b 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
@@ -17,13 +17,3 @@ from Standard.Builtins import Builtins
 Array.to_default_visualization_data : Text
 Array.to_default_visualization_data =
     Vector.Vector this . to_default_visualization_data
-
-## PRIVATE
-   Copy the backing Array to an Enso Array
-   TODO This is a workaround for the issue with polyglot Array.copy
-        https://www.pivotaltracker.com/story/show/181122542
-Array.copy_to : Array->Integer->Array->Integer->Integer
-Array.copy_to src_array src_start dest_array dest_start length =
-    case Builtins.Meta.is_polyglot src_array of
-        True -> 0.up_to length . each i->(dest_array.set_at (i+dest_start) (src_array.at i+src_start))
-        False -> Array.copy src_array src_start dest_array dest_start length
diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 86e8e6fe7b8d..3dbbe73e94fb 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -464,7 +464,7 @@ type Vector
         length = this.fold 0 acc-> elem-> acc + elem.length
         arr = Array.new length
         this.fold 0 i-> vec->
-            Array.copy_to vec.to_array 0 arr i vec.length
+            Array.copy vec.to_array 0 arr i vec.length
             i + vec.length
         Vector arr
 
@@ -595,8 +595,8 @@ type Vector
     + that =
         this_len = this.length
         arr = Array.new (this_len + that.length)
-        Array.copy_to this.to_array 0 arr 0 this_len
-        Array.copy_to that.to_array 0 arr this_len that.length
+        Array.copy this.to_array 0 arr 0 this_len
+        Array.copy that.to_array 0 arr this_len that.length
         Vector arr
 
     ## Add `element` to the beginning of `this` vector.
@@ -660,7 +660,7 @@ type Vector
             if (slice_start == 0) && (slice_end == this.length) then this else
                 len = slice_end - slice_start
                 arr = Array.new len
-                Array.copy_to this.to_array slice_start arr 0 len
+                Array.copy this.to_array slice_start arr 0 len
                 Vector arr
 
     ## Creates a new vector with the first `count` elements in `this` removed.
@@ -890,7 +890,7 @@ type Vector
            not want to sort in place on the original vector, as `sort` is not
            intended to be mutable.
         new_vec_arr = Array.new this.length
-        Array.copy_to this.to_array 0 new_vec_arr 0 this.length
+        Array.copy this.to_array 0 new_vec_arr 0 this.length
 
         ## As we want to account for both custom projections and custom
            comparisons we need to construct a comparator for internal use that
diff --git a/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CopyNode.java b/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CopyNode.java
index 4043300acf11..8559f8a5adfa 100644
--- a/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CopyNode.java
+++ b/engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/CopyNode.java
@@ -1,5 +1,6 @@
 package org.enso.interpreter.node.expression.builtin.mutable;
 
+import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.CachedContext;
 import com.oracle.truffle.api.dsl.Fallback;
 import com.oracle.truffle.api.dsl.Specialization;
@@ -10,6 +11,7 @@
 import com.oracle.truffle.api.nodes.Node;
 import org.enso.interpreter.Language;
 import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.node.expression.builtin.interop.syntax.HostValueToEnsoNode;
 import org.enso.interpreter.runtime.Context;
 import org.enso.interpreter.runtime.builtin.Builtins;
 import org.enso.interpreter.runtime.data.Array;
@@ -48,24 +50,25 @@ Object doPolyglotArray(
       long dest_index,
       long count,
       @CachedLibrary(limit = "3") InteropLibrary arrays,
-      @CachedContext(Language.class) Context ctx) {
+      @Cached HostValueToEnsoNode hostValueToEnsoNode) {
     try {
       for (int i = 0; i < count; i++) {
-        dest.getItems()[(int) dest_index + i] = arrays.readArrayElement(src, source_index + i);
+        dest.getItems()[(int) dest_index + i] = hostValueToEnsoNode.execute(
+            arrays.readArrayElement(src, source_index + i));
       }
     } catch (UnsupportedMessageException e) {
       throw new IllegalStateException("Unreachable");
     } catch (InvalidArrayIndexException e) {
       throw new PanicException(
-          ctx.getBuiltins().error().makeInvalidArrayIndexError(src, e.getInvalidIndex()), this);
+          Context.get(this).getBuiltins().error().makeInvalidArrayIndexError(src, e.getInvalidIndex()), this);
     }
-    return ctx.getBuiltins().nothing().newInstance();
+    return  Context.get(this).getBuiltins().nothing().newInstance();
   }
 
   @Fallback
   Object doOther(
       Object _this, Object src, long source_index, Array dest, long dest_index, long count) {
-    Builtins builtins = lookupContextReference(Language.class).get().getBuiltins();
+    Builtins builtins = Context.get(this).getBuiltins();
     throw new PanicException(
         builtins.error().makeTypeError(builtins.mutable().array().newInstance(), src, "src"), this);
   }

From 13711fb17ebe2d454369a4f2e89b88579e839527 Mon Sep 17 00:00:00 2001
From: James Dunkerley <jdunkerley@users.noreply.github.com>
Date: Thu, 3 Mar 2022 13:04:08 +0000
Subject: [PATCH 19/20] Update
 distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso

Co-authored-by: Marcin Kostrzewa <marckostrzewa@gmail.com>
---
 distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
index 3dbbe73e94fb..1f293a03d7ef 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Vector.enso
@@ -302,7 +302,7 @@ type Vector
 
              [-1, 1, 5, 8].all (< 0)
     all : (Any -> Boolean) -> Boolean
-    all predicate = (this.exists (r -> (predicate r).not)).not
+    all predicate = this . exists (predicate >> .not) . not
 
     ## Checks whether this vector contains a given value as an element.
 

From 12c81f3d880a140f57c24fceb763778b149d0128 Mon Sep 17 00:00:00 2001
From: James Dunkerley <jdunkerley@users.noreply.github.com>
Date: Thu, 3 Mar 2022 13:05:53 +0000
Subject: [PATCH 20/20] Update Extensions.enso

---
 .../lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso   | 1 -
 1 file changed, 1 deletion(-)

diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
index c22476f3788b..caa2b106f2f8 100644
--- a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
+++ b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Array/Extensions.enso
@@ -1,5 +1,4 @@
 from Standard.Base import all
-from Standard.Builtins import Builtins
 
 ## UNSTABLE
    ADVANCED