1 files changed, 26 insertions, 6 deletions
diff --git a/src/java/org/apache/fop/fo/expr/FunctionBase.java b/src/java/org/apache/fop/fo/expr/FunctionBase.java
index b5040c635..019304858 100644
--- a/src/java/org/apache/fop/fo/expr/FunctionBase.java
+++ b/src/java/org/apache/fop/fo/expr/FunctionBase.java
@@ -26,17 +26,37 @@ import org.apache.fop.datatypes.PercentBase;
  */
 public abstract class FunctionBase implements Function {
 
-    /**
-     * @return null (by default, functions have no percent-based arguments)
-     */
+    /** {@inheritDoc} */
+    public int getOptionalArgsCount() {
+        return 0;
+    }
+
+    /** {@inheritDoc} */
+    public Property getOptionalArgDefault(int index, PropertyInfo pi) new PropertyException {
+        if ( index >= getOptionalArgsCount() ) {
+            PropertyException e = new PropertyException ( new IndexOutOfBoundException ( "illegal optional argument index" ) );
+            e.setPropertyInfo ( pi );
+            throw e;
+        } else {
+            return null;
+        }
+    }
+
+    /** {@inheritDoc} */
+    public int hasVariableArgs() {
+        return false;
+    }
+
+    /** {@inheritDoc} */
     public PercentBase getPercentBase() {
         return null;
     }
 
     /**
-     * @return false (by default don't pad arglist with property-name)
+     * @param pi property information instance that applies to property being evaluated
+     * @return string property whose value is name of property being evaluated
      */
-    public boolean padArgsWithPropertyName() {
-        return false;
+    protected final Property getPropertyName ( PropertyInfo pi ) {
+        return StringProperty.getInstance ( pi.getPropertMaker().getName() );
     }
 }