Add support for while loops (#7101)

crates/nu-command/tests/commands/mod.rs

@@ -88,6 +88,7 @@ mod use_;
 mod where_;
 #[cfg(feature = "which-support")]
 mod which;
+mod while_;
 mod with_env;
 mod wrap;
 mod zip;

crates/nu-command/tests/commands/while_.rs

@@ -0,0 +1,11 @@
+use nu_test_support::nu;
+
+#[test]
+fn while_sum() {
+    let actual = nu!(
+        cwd: ".",
+        "mut total = 0; mut x = 0; while $x <= 10 { $total = $total + $x; $x = $x + 1 }; $total"
+    );
+
+    assert_eq!(actual.out, "55");
+}