Add advanced Decodal example

examples/advanced/schema.dcdl

@@ -0,0 +1,17 @@
+# Shared service schema.
+# Top-level fields are recursive, so SecurePort can refer to Port.
+
+Port = Int & >= 1 & <= 65535;
+SecurePort = Port & > 443;
+
+Service = {
+  name = String;
+  env = String default "dev";
+  host = String default "localhost";
+  port = SecurePort default 8443;
+
+  feature = {
+    enable = Bool default true;
+    limit = Int & >= 0 default 10;
+  };
+};