Add array:to() to split out functionality of array:from()

2 files changed, 22 insertions, 7 deletions

diff --git a/builtins/array.c b/builtins/array.c
index 1c31be80..2d45591c 100644
--- a/builtins/array.c
+++ b/builtins/array.c
@@ -261,24 +261,38 @@ public array_t Array$sample(array_t arr, int64_t n, array_t weights, const TypeI
     return selected;
 }
 
-public array_t Array$from(array_t *array, int64_t first, int64_t last)
+public array_t Array$from(array_t *array, int64_t first)
 {
     if (first < 0)
         first = array->length + first + 1;
 
+    if (first < 1 || first > array->length)
+        return (array_t){.atomic=array->atomic};
+
+    return (array_t){
+        .atomic=array->atomic,
+        .data=array->data + array->stride*(first-1),
+        .length=array->length - first + 1,
+        .stride=array->stride,
+        .data_refcount=array->data_refcount,
+    };
+}
+
+public array_t Array$to(array_t *array, int64_t last)
+{
     if (last < 0)
         last = array->length + last + 1;
 
-    if (first < 1 || first > array->length || last < first)
-        return (array_t){.atomic=array->atomic};
-
     if (last > array->length)
         last = array->length;
 
+    if (last == 0)
+        return (array_t){.atomic=array->atomic};
+
     return (array_t){
         .atomic=array->atomic,
-        .data=array->data + array->stride*(first-1),
-        .length=last - first + 1,
+        .data=array->data,
+        .length=last,
         .stride=array->stride,
         .data_refcount=array->data_refcount,
     };
diff --git a/builtins/array.h b/builtins/array.h
index b2884d99..56794a22 100644
--- a/builtins/array.h
+++ b/builtins/array.h
@@ -64,7 +64,8 @@ array_t Array$sample(array_t arr, int64_t n, array_t weights, const TypeInfo *ty
 void Array$clear(array_t *array);
 void Array$compact(array_t *arr, const TypeInfo *type);
 bool Array$contains(array_t array, void *item, const TypeInfo *type);
-array_t Array$from(array_t *array, int64_t first, int64_t last);
+array_t Array$from(array_t *array, int64_t first);
+array_t Array$to(array_t *array, int64_t last);
 array_t Array$by(array_t *array, int64_t stride);
 array_t Array$reversed(array_t array);
 array_t Array$concat(array_t x, array_t y, const TypeInfo *type);