diff --git a/source/net/sourceforge/filebot/format/ExpressionBindings.java b/source/net/sourceforge/filebot/format/ExpressionBindings.java
index ca295fcf..96c63809 100644
--- a/source/net/sourceforge/filebot/format/ExpressionBindings.java
+++ b/source/net/sourceforge/filebot/format/ExpressionBindings.java
@@ -1,7 +1,5 @@
-
 package net.sourceforge.filebot.format;
 
-
 import java.lang.reflect.Method;
 import java.util.AbstractMap;
 import java.util.HashSet;
@@ -13,59 +11,61 @@ import javax.script.Bindings;
 
 import net.sourceforge.tuned.ExceptionUtilities;
 
-
 public class ExpressionBindings extends AbstractMap<String, Object> implements Bindings {
-	
+
 	protected final Object bindingBean;
-	
+
 	protected final Map<String, Method> bindings = new TreeMap<String, Method>(String.CASE_INSENSITIVE_ORDER);
-	
+
 	protected final Method undefined;
-	
 
 	public ExpressionBindings(Object bindingBean) {
 		this.bindingBean = bindingBean;
-		
+
 		// get method bindings
 		for (Method method : bindingBean.getClass().getMethods()) {
 			Define define = method.getAnnotation(Define.class);
-			
+
 			if (define != null) {
 				for (String name : define.value()) {
 					Method existingBinding = bindings.put(name, method);
-					
+
 					if (existingBinding != null)
 						throw new IllegalArgumentException(String.format("Illegal binding {%s} on %s", name, method.getName()));
 				}
 			}
 		}
-		
+
 		// extract mapping that handles undefined bindings
 		undefined = bindings.remove(Define.undefined);
 	}
-	
+
+	protected boolean isUndefined(Object value) {
+		if (value instanceof CharSequence) {
+			return ((CharSequence) value).length() <= 0;
+		}
+		return value == null;
+	}
 
 	public Object getBindingBean() {
 		return bindingBean;
 	}
-	
 
 	protected Object evaluate(final Method method) throws Exception {
 		Object value = method.invoke(bindingBean);
-		
-		if (value != null) {
+
+		if (!isUndefined(value)) {
 			return value;
 		}
-		
+
 		// invoke fallback method
 		return undefined.invoke(bindingBean);
 	}
-	
 
 	@Override
 	public Object get(Object key) {
 		Method method = bindings.get(key);
-		
+
 		if (method != null) {
 			try {
 				return evaluate(method);
@@ -73,61 +73,53 @@ public class ExpressionBindings extends AbstractMap<String, Object> implements B
 				throw new BindingException(key.toString(), ExceptionUtilities.getRootCauseMessage(e), e);
 			}
 		}
-		
+
 		return null;
 	}
-	
 
 	@Override
 	public Object put(String key, Object value) {
 		// bindings are immutable
 		return null;
 	}
-	
 
 	@Override
 	public Object remove(Object key) {
 		// bindings are immutable
 		return null;
 	}
-	
 
 	@Override
 	public boolean containsKey(Object key) {
 		return bindings.containsKey(key);
 	}
-	
 
 	@Override
 	public Set<String> keySet() {
 		return bindings.keySet();
 	}
-	
 
 	@Override
 	public boolean isEmpty() {
 		return bindings.isEmpty();
 	}
-	
 
 	@Override
 	public Set<Entry<String, Object>> entrySet() {
 		Set<Entry<String, Object>> entrySet = new HashSet<Entry<String, Object>>();
-		
+
 		for (final String key : keySet()) {
 			entrySet.add(new Entry<String, Object>() {
-				
+
 				@Override
 				public String getKey() {
 					return key;
 				}
-				
 
 				@Override
 				public Object getValue() {
 					return get(key);
 				}
-				
 
 				@Override
 				public Object setValue(Object value) {
@@ -135,8 +127,8 @@ public class ExpressionBindings extends AbstractMap<String, Object> implements B
 				}
 			});
 		}
-		
+
 		return entrySet;
 	}
-	
+
 }
diff --git a/source/net/sourceforge/filebot/format/ExpressionFormat.lib.groovy b/source/net/sourceforge/filebot/format/ExpressionFormat.lib.groovy
index 77ad0500..65e5e23a 100644
--- a/source/net/sourceforge/filebot/format/ExpressionFormat.lib.groovy
+++ b/source/net/sourceforge/filebot/format/ExpressionFormat.lib.groovy
@@ -172,7 +172,7 @@ String.metaClass.ascii = { fallback = ' ' -> delegate.transliterate("Any-Latin;L
 /**
  * General helpers and utilities
  */
-def c(c) {
+def c(Closure c) {
 	try {
 		return c.call()
 	} catch (Throwable e) {
@@ -180,6 +180,26 @@ def c(c) {
 	}
 }
 
+def	any(Closure... closures) {
+	return closures.findResult{ c ->
+		try {
+			return c.call()
+		} catch (Throwable e) {
+			return null
+		}
+	}
+}
+
+def	allOf(Closure... closures) {
+	return closures.toList().findResults{ c ->
+		try {
+			return c.call()
+		} catch (Throwable e) {
+			return null
+		}
+	}
+}
+
 def csv(path, delim = ';', keyIndex = 0, valueIndex = 1) {
 	def f = path as File
 	def values = [:]