added Automatic-Module-Name to jar manifest and some utility methods

build.sbt

@@ -27,6 +27,10 @@ javacOptions in (Compile, compile) ++= Seq("-target", "8", "-source", "8")
 libraryDependencies += "org.projectlombok" % "lombok" % "1.18.8" % Provided
 libraryDependencies += "net.woggioni" % "jwo" % "1.0" % Compile
 
+Compile / packageBin / packageOptions +=
+  Package.ManifestAttributes("Automatic-Module-Name" -> "net.woggioni.worth")
+
+
 val testDependencies = Seq("com.novocode" % "junit-interface" % "0.11" % Test,
                            "com.fasterxml.jackson.core" % "jackson-databind" % "2.9.6" % Test,
                            "org.tukaani" % "xz" % "1.8" % Test)

src/main/java/net/woggioni/worth/utils/WorthUtils.java

@@ -3,11 +3,23 @@ package net.woggioni.worth.utils;
 import lombok.SneakyThrows;
 import net.woggioni.worth.xface.Value;
 
+import java.util.Optional;
 import java.util.function.Function;
 import java.util.function.Supplier;
 
 public class WorthUtils {
-    
+
+    public static Optional<Value> nested(Value root, String... keys) {
+        Value result = root;
+        for (String key : keys) {
+            result = result.get(key);
+            if (result == null) {
+                break;
+            }
+        }
+        return Optional.ofNullable(result);
+    }
+
     public static Value getOrNull(Value root, String... keys) {
         Value result = root;
         for (String key : keys) {

src/main/java/net/woggioni/worth/xface/Value.java

@@ -18,6 +18,10 @@ public interface Value {
 
     Type type();
 
+    default boolean isNull() {
+        return type() == Value.Null.type();
+    }
+
     default boolean asBoolean() {
         throw new TypeException("Not a boolean");
     }