Add a zip method to arrays (#947)

docs/src/reference/types.md

@@ -620,6 +620,16 @@ for loop.
 
 - returns: array
 
+### zip()
+Zips the array with another array. If the two arrays are of unequal length, it
+will only zip up until the last element of the smaller array and the remaining
+elements will be ignored. The return value is an array where each element is yet
+another array of size 2.
+
+- other: array (positional, required)
+  The other array which should be zipped with the current one.
+- returns: array
+
 ### fold()
 Folds all items into a single value using an accumulator function.
 

src/eval/array.rs

@@ -306,6 +306,18 @@ impl Array {
         Ok(result)
     }
 
+    /// Zips the array with another array. If the two arrays are of unequal length, it will only
+    /// zip up until the last element of the smaller array and the remaining elements will be
+    /// ignored. The return value is an array where each element is yet another array of size 2.
+    pub fn zip(&self, other: Array) -> Array {
+        self.iter()
+            .zip(other)
+            .map(|(first, second)| {
+                Value::Array(Array::from_vec(eco_vec![first.clone(), second]))
+            })
+            .collect()
+    }
+
     /// Return a sorted version of this array, optionally by a given key function.
     ///
     /// Returns an error if two values could not be compared or if the key function (if given)

src/eval/methods.rs

@@ -118,6 +118,7 @@ pub fn call(
                 array.join(sep, last).at(span)?
             }
             "sorted" => Value::Array(array.sorted(vm, span, args.named("key")?)?),
+            "zip" => Value::Array(array.zip(args.expect("other")?)),
             "enumerate" => Value::Array(array.enumerate()),
             _ => return missing(),
         },
@@ -319,6 +320,7 @@ pub fn methods_on(type_name: &str) -> &[(&'static str, bool)] {
             ("slice", true),
             ("sorted", false),
             ("enumerate", false),
+            ("zip", true),
         ],
         "dictionary" => &[
             ("at", true),

tests/typ/compiler/array.typ

@@ -223,6 +223,17 @@
 #test((2, 1, 3, -10, -5, 8, 6, -7, 2).sorted(key: x => x), (-10, -7, -5, 1, 2, 2, 3, 6, 8))
 #test((2, 1, 3, -10, -5, 8, 6, -7, 2).sorted(key: x => x * x), (1, 2, 2, 3, -5, 6, -7, 8, -10))
 
+---
+// Test the `zip` method.
+#test(().zip(()), ())
+#test((1,).zip(()), ())
+#test((1,).zip((2,)), ((1, 2),))
+#test((1, 2).zip((3, 4)), ((1, 3), (2, 4)))
+#test((1, 2, 3, 4).zip((5, 6)), ((1, 5), (2, 6)))
+#test(((1, 2), 3).zip((4, 5)), (((1, 2), 4), (3, 5)))
+#test((1, "hi").zip((true, false)), ((1, true), ("hi", false)))
+
+
 ---
 // Error: 32-37 cannot divide by zero
 #(1, 2, 0, 3).sorted(key: x => 5 / x)