[function.dd] Explain why a Lazy Variadic Delegate is better than a Lazy Variadic Array

Author: ntrel

spec/function.dd

@@ -1715,6 +1715,25 @@ foo(1, 3+x, dg, cast(int delegate())null);
 
 ---
 foo( { return 1; }, { return 3+x; }, dg, null );
+---
+
+        $(P The lazy variadic delegate solution is preferable to using a lazy
+        variadic array, because each array index would evaluate every element:)
+
+---
+import std.stdio;
+
+void foo(lazy int[] arr...)
+{
+    writeln(arr[0]); // 1
+    writeln(arr[1]); // 4, not 2
+}
+
+void main()
+{
+    int x;
+    foo(++x, ++x);
+}
 ---
 
 $(H2 $(LEGACY_LNAME2 Local Variables, local-variables, Local Variables))