--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xml/xmldomandxpath/inc/xpath/xmlengxpathextensionfunction.h	Thu Dec 17 09:29:21 2009 +0200
@@ -0,0 +1,93 @@
+// Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of "Eclipse Public License v1.0"
+// which accompanies this distribution, and is available
+// at the URL "http://www.eclipse.org/legal/epl-v10.html".
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+// Extension function interface
+//
+
+
+
+/**
+ @file
+ @publishedAll
+ @released
+*/
+#ifndef XMLENGXPATHFUNCTION_H
+#define XMLENGXPATHFUNCTION_H
+
+#include <xml/dom/xmlengxpathresult.h>
+
+class MXmlEngXPathEvaluationContext;
+
+/**
+Provides an interface for an object to participate in the evaluation of XPath
+expression via a XPath function call.
+
+Objects that implement the MXmlEngXPathExtensionFunction interface can be
+registered in a XmlEngXPathConfiguration object for global action (across
+all evaluations globally). 
+
+@see XmlEngXPathConfiguration::AddExtensionFunctionL()
+
+When the extension function is no longer required, it must be deregistered
+by calling XmlEngXPathConfiguration::RemoveExtensionFunction().
+*/ 
+class MXmlEngXPathExtensionFunction
+    {
+public:
+    /** Evaluation status */
+    enum TXmlEngEvaluationStatus
+        {
+		/** Evaluation was accomplished successfully */
+        ESucceeded,
+		/** An exceptional condition occurs */
+        EError,
+		/** Type of argument does not match function specification */
+        EInvalidArgumentType,
+		/** Number of arguments do not match function specification */
+        EInvalidArgumentNumber
+        };
+        
+public:
+    /** 
+    Gets the minimum number of arguments the function can take.
+    @return Minimum number of arguments
+    */
+    virtual TInt MinArity() {return 0;}
+
+    /** 
+    Gets the maximum number of arguments the function can take.
+    
+	@return The maximum number of arguments or -1 if unbounded
+    */
+    virtual TInt MaxArity() {return MinArity();}
+
+    /**
+	Called to evaluate the extension function.
+
+	This function is called only if simple arity constraints (min/max number of
+	arguments) are satisfied. The implementation of this function may need to
+	check further that the types of arguments and their positions in the
+	function call match function-specific requirements.
+    
+	@param aEvalCtxt Evaluation context, which contains data about arguments
+	and provides a number of methods for setting the result of the extension
+	function.
+
+    @return ESucceeded if evaluation success, otherwise one of the errors 
+	defined in TXmlEngEvaluationStatus.
+    */
+    virtual TXmlEngEvaluationStatus Evaluate(MXmlEngXPathEvaluationContext* aEvalCtxt) = 0; 
+    };
+
+#endif /* XMLENGXPATHFUNCTION_H */
+