1. DOM: Towards a Formal Specification Author: Mark Wheelhouse Supervisor: Dr. Philippa Gardner Thanks to: Gareth Smith, Uri Zarfaty, Ian Hodkinson

2. DOM (Document Object Model) Current Spec. English English Verbose Verbose Ambiguous Ambiguous Automated Verification Automated Verification Not Possible Not Possible Extensions Extensions Hard Hard Time-consuming Time-consuming What We Want Formalism Formalism Data Structure Logical Framework Automated Verification Automated Verification Possible Extensions Extensions Easier Quicker

3. What is DOM? DOM Tree High Level XML Update High Level XML Update W3C W3C Aimed at Object Aimed at Object Orientated Programmers Orientated Programmers Stores XML in Tree Structure Stores XML in Tree Structure

4. Minimal DOM DOM Core Level 3 DOM Core Level 2 DOM Core Level 1 Application Based Consider Structural Behaviour Only

5. Minimal DOM createNodegetNodeNamegetChildNodesappendgetLengthgetItemgetParentNodeinsertBeforeremoveChild

6. createNodegetNodeNamegetChildNodesappendgetLengthgetItemgetParentNodeinsertBeforeremoveChild

7. Context Logic Local Reasoning Tool for Tree Update Local Reasoning Tool for Tree Update Proved Correct Proved Correct Used on Toy Examples Used on Toy Examples Provides Compositional Reasoning Provides Compositional Reasoning First Real-World Test First Real-World Test

8. Context Logic - Application Pre: PCommand: C Post: Q

9. Context Logic – Right Triangle K = (P Q)

10. Data Structure

11. Command Axioms Command Axioms { Pre-condition } { Post-condition } Command Specifying the Local Behaviour of the commands:

12. getNodeName tag’ = getNodeName(id); tag’ = tag

13. getNodeName - Small Axiom

14. Weakest Pre-condition

18. insertBefore insertBefore(parent, newChild, ref);

19. Ancestor Issue

20. insertBefore - Axiom Why not Small ?

21. Weakest Pre-condition

23. Axiom Composition - insertAfter insertBefore(parent, newChild, ref);insertBefore(parent, ref, newChild);

24. Axiom Composition - insertAfter

25. More than Minimal DOM cloneNodereplaceChildhasChildNodes insertAfter nodeEquality DOM Core Level 1:

26. Conclusion Complete Spec. for Minimal DOM Complete Spec. for Minimal DOM Complete Spec. for Structural DOM Core Level 1 Complete Spec. for Structural DOM Core Level 1 Highly Extendable Highly Extendable Automated Verification now possible Automated Verification now possible

27. Future Work Automated Verification Tool Automated Verification Tool Getting it Small Getting it Small The Rest of Core Level 1 The Rest of Core Level 1 Higher Levels of DOM Higher Levels of DOM Concurrent DOM Concurrent DOM