Add at_or returing n-th value or default

tweag · May 21, 2024 · e224f7e · e224f7e
1 parent ea41f82
commit e224f7e
Showing 1 changed file with 19 additions and 0 deletions.
diff --git a/core/stdlib/std.ncl b/core/stdlib/std.ncl
@@ -172,6 +172,25 @@
         "%
       = fun n l => %elem_at% l n,
 
+    at_or
+      : forall a. Number -> a -> Array a -> a
+      | doc m%"
+          Retrieves the n-th element from an array, with indices starting at 0
+          or provided value in case index is out of bounds.
+
+          # Examples
+
+          ```nickel
+          std.array.at 3 "default" [ "zero", "one" ] =>
+            "default"
+          ```
+        "%
+      = fun n default_value l =>
+        if n < %length% then
+          %elem_at% l n
+        else
+          default_value,
+
     concat
       : forall a. Array a -> Array a -> Array a
       | doc m%"