1. Bidirectional Transformation
of
Model-Driven Spreadsheets
come Cunha1, Joã P. Fernandes12, Jorge Mendes1,
Já o
Hugo Pacheco1, Joã Saraiva1
o
1
HASLab / INESC TEC & Universidade do Minho, Portugal
2
Universidade do Porto, Portugal
ICMT 2012

2. Agenda
● Introduction
● ClassSheets as Spreadsheet Models
● Bidirectional Spreadsheet Evolution Environment
● MDSheet Framework
● Implementation
● Conclusions and Future Work
2

3. Introduction
3

4. Spreadsheets
● Highly flexible end-users programming environment
● highly error prone
● Widely used for decision making
● potential negative economic impact
● Do you agree?
4

5. 5
http://www.wiscnews.com/baraboonewsrepublic/news/local/article_7672b6c6-22d5-11e1-8398-001871e3ce6c.html

6. 6
http://www.sltrib.com/sltrib/news/53893888-78/state-error-office-education.html.csp
http://www.sltrib.com/sltrib/news/54128921-78/session-education-special-lawmakers.html.csp

7. Many More Horror Stories
● EuSpRIG Original Horror Stories
● http://www.eusprig.org/stories.htm 7

8. Why Spreadsheet Models?
● In many cases spreadsheets start simple
● They get bigger and bigger
● Many rows, columns, worksheets,
dependencies, etc.
● Harder and harder to understand
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9. Why Spreadsheet Models?
● Models allow to abstract and better understand
the underlying problem
● ClassSheet models allow to specify
spreadsheets
● Introduced by Engels and Erwig to model the
business logic of spreadsheet data
● They allow to model spreadsheets using object-
oriented concepts
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10. Overview of our Solution
● We infer models from spreadsheet data
(VL/HCC '10)
● We embed such models in
OpenOffice/LibreOffice providing a MDE
environment (VL/HCC '11, ICSE '12)
Conforms
Model Instance
ClassSheet Spreadsheet data
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11. Model-Driven Spreadsheet Environment
(Instance/Data Worksheet)
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12. Model-Driven Spreadsheet Environment
(Model/ClassSheet Worksheet)
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13. 13

14. Our Work
● In previous work we used data refinement to
allow model evolution and co-evolution of data
(FASE '11 / VL/HCC '11)
● In this paper:
● We define a bidirectional transformational
system to allow both model and instance
evolution and co-evolution
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15. ClassSheets as Spreadsheet Models
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16. Vertically Expandable Tables
Spreadsheet Data ClassSheet Model
16

17. Horizontally Expandable Tables
Spreadsheet Data ClassSheet Model
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18. Relationship Tables
Spreadsheet Data
ClassSheet Model
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19. Limitations
● It is not possible to edit/evolve the data
structure
● Too restrictive to regular spreadsheet users
● Some transformations are not easy to perform
on the model
● Changing the data and inferring a new model is
easier
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20. The MDSheet Framework
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21. Combining Techniques
● Embedding of ClassSheet models
● Framework for bidirectional transformations
● Extending OpenOffice/LibreOffice
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22. Bidirectional Transformation System
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23. Architecture
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24. Example of a Transformation we Want:
Add a New Column
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25. (Model) Operations on ClassSheets
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26. (Data) Operations on Instances
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27. Bidirectional Transformation Functions
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28. Example: Add a Column and a Class
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29. Bidirectional Transformation Properties
● Correctness
● Hippocraticness (from)
● Invertibillity (to)
● History ignorance
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30. Conclusions and Future Work
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31. Conclusions
● Framework for bidirectional transformations
● When evolving the data a new model is inferred
● When evolving the model the data changes
● The data always conforms to the model
● Available as a OpenOffice/LibreOffice
extension
● Tool demo next week at ICSE
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32. Future Work
● We want to consider more than one instance of
each model
● Use automata to formalize ClassSheets
● Create an algebra
● Check model properties
● Evolve in a specified direction
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33. Thank you!
http://ssaapp.di.uminho.pt
http://wiki.di.uminho.pt/twiki/bin/view/Research/FATBIT/WebHome
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